Wissler syndrome

Immune MONDO:0006018 Pathograph 23 Show in embeddings browser rheumatic disorder syndromic disease

Wissler syndrome (Wissler-Fanconi syndrome; historically "subsepsis allergica") is a rare descriptive rheumatic syndrome defined by recurrent high fever, polymorphous exanthem, leukocytosis, and arthralgia. Its nosologic identity remains disputed: publications have treated it as a separate entity, an early or atypical Still-disease presentation, or a broad historical label spanning several modern diagnoses. No disease-specific molecular mechanism is established. Innate-immune mechanisms and biologic treatments established for adult-onset Still disease are therefore represented here only as conditional extrapolations, not as proven Wissler-syndrome biology or management.

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7
Pathophys.
12
Phenotypes
2
Hypotheses
3
Gaps
23
Pathograph
7
Medical Actions
8
Differentials
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Classifications

Harrison's Part
IMMUNE RHEUMATOLOGIC
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Mechanistic Hypotheses

2
Conditional Still-Spectrum Extrapolation
still_spectrum_extrapolation ALTERNATIVE
Evidence balance 3 support
If a presentation historically labelled Wissler syndrome is an early or atypical form of Still disease, AOSD monocyte/macrophage, inflammasome, and IL-1/IL-18 mechanisms may apply. This conditional model is supported by proposed nosologic overlap, the contemporary consensus that unified the Still-disease spectrum, and a recent case-report framing, not by Wissler-specific molecular studies.
Pathograph links
Still-spectrum monocyte and macrophage activation (extrapolated) -> Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated) DIRECT In AOSD, the reviewed stimuli activate NLRP3 and caspase-1, producing mature IL-1β and IL-18.
Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated) -> Recurrent systemic inflammatory episodes UNKNOWN AOSD literature links IL-1β/IL-18 to clinical manifestations, but the causal bridge has not been demonstrated in Wissler-labelled patients.
Show evidence (3 references)
PMID:39317417 SUPPORT Other
"sJIA and AOSD are one disease, to be designated by one name, Still's disease."
EULAR/PReS consensus unifies systemic juvenile idiopathic arthritis and adult-onset Still disease into a single entity, establishing the Still-disease spectrum that this hypothesis would extrapolate from. It does not place Wissler syndrome inside that spectrum, so the support is partial.
PMID:8150635 SUPPORT Human Clinical
"This syndrome has sometimes been considered equivalent to or an initial stage of Still's disease (juvenile rheumatoid arthritis) progressing to degenerative arthritis in many patients, whereas other authors have classified it as a separate entity with good prognosis."
Supports historical Still overlap while explicitly documenting a competing interpretation.
PMID:41737969 SUPPORT Human Clinical
"Recognition of the Wissler-Fanconi variant and early ferritin testing can prevent diagnostic delay and enable prompt, effective immunosuppressive therapy."
A recent single case report frames Wissler-Fanconi syndrome as an AOSD variant; its evidentiary weight is insufficient to settle the nosology.
Distinct Historical Syndrome
distinct_historical_syndrome ALTERNATIVE
Evidence balance 2 support
Wissler syndrome may be a separate clinicopathologic entity defined by its recurrent febrile-exanthem-leukocytosis-arthralgia pattern. Under this model, its cause remains unknown and Still-disease mechanisms cannot be assumed.
Show evidence (2 references)
PMID:3092775 SUPPORT Human Clinical
"The Wissler-Fanconi syndrome is an inflammatory disease of unknown origin, similar to Still's disease, a systemic form of juvenile arthritis."
Describes unknown origin and similarity, rather than demonstrated identity, with Still disease.
PMID:8150635 SUPPORT Human Clinical
"This syndrome has sometimes been considered equivalent to or an initial stage of Still's disease (juvenile rheumatoid arthritis) progressing to degenerative arthritis in many patients, whereas other authors have classified it as a separate entity with good prognosis."
Directly documents the historical separate-entity interpretation.
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Discussions and Knowledge Gaps

3
Is Wissler syndrome a distinct entity, an early or atypical Still-disease presentation, or a historical umbrella that combines several modern diagnoses?
CONTROVERSY OPEN wissler-nosologic-boundary
Attached to
mechanistic_hypotheses#still_spectrum_extrapolation mechanistic_hypotheses#distinct_historical_syndrome diagnosis#Historical descriptive clinical pattern
The literature explicitly presents competing interpretations. A 1994 report records both equivalence/initial-stage and separate-entity views; a 2016 case report says the boundary remains open to debate; a 2026 case report uses a Still-variant framing but cannot settle the issue alone. The answer controls whether AOSD mechanism and treatment evidence can be transferred.
Proposed experiments
Prospective multicenter nosology cohort
prospective-wissler-nosology-cohort
Enroll patients meeting the historical fever-exanthem-leukocytosis-arthralgia pattern before final diagnosis. Apply standardized infectious, malignant, rheumatic-fever, rheumatoid-arthritis, systemic-JIA, and AOSD evaluations; collect longitudinal phenotypes, serial cytokines, ferritin, and single-cell immune profiles; and adjudicate final diagnoses blinded to molecular clustering.
Readouts
Concordance of historical phenotype with contemporary diagnosis and immune cluster
pathophysiology#Recurrent systemic inflammatory episodes
Decision criterion
A reproducible cluster that aligns with contemporary Still disease would support transfer of Still mechanisms; a distinct reproducible cluster would support a separate entity; heterogeneous final diagnoses without a shared profile would support an umbrella-label interpretation.
Show evidence (3 references)
PMID:8150635 SUPPORT Human Clinical
"This syndrome has sometimes been considered equivalent to or an initial stage of Still's disease (juvenile rheumatoid arthritis) progressing to degenerative arthritis in many patients, whereas other authors have classified it as a separate entity with good prognosis."
Explicitly documents the two competing historical interpretations.
PMID:27843372 SUPPORT Human Clinical
"This syndrome was considered by some authors as a premature stage of adult Still’s disease, whereas other authors considered it a separate entity, and this remains open to debate."
Explicitly states that the nosologic boundary remains unresolved.
PMID:41737969 SUPPORT Human Clinical
"Recognition of the Wissler-Fanconi variant and early ferritin testing can prevent diagnostic delay and enable prompt, effective immunosuppressive therapy."
Provides a recent, but single-case, Still-variant interpretation.
Do patients prospectively identified by the historical Wissler pattern show the monocyte/macrophage and NLRP3-IL-1/IL-18 state described in AOSD?
KNOWLEDGE GAP OPEN wissler-mechanism-validation
Attached to
pathophysiology#Still-spectrum monocyte and macrophage activation (extrapolated) pathophysiology#Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
The mechanistic evidence currently comes from AOSD, and no disease-specific experimental model, cohort-scale cytokine study, or omics dataset was identified. Importing an AOSD model would assume the disputed equivalence.
Proposed experiments
Blinded Wissler-pattern versus AOSD immune comparison
wissler-aosed-mechanism-comparison
Compare prospectively collected Wissler-pattern cases, criteria-confirmed AOSD/systemic JIA, febrile infectious controls, and inflammatory controls using serial monocyte activation phenotyping, inflammasome activity, IL-1β/IL-18 measurements, and single-cell transcriptomics before major immunosuppression.
Readouts
Reproducible monocyte and inflammasome signature by adjudicated diagnosis
pathophysiology#Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
Decision criterion
A replicated signature matching Still disease after exclusion of mimics would support the conditional mechanism; absence of that signature or separation into heterogeneous disease-specific profiles would refute its use as a general Wissler mechanism.
Show evidence (2 references)
PMID:3092775 SUPPORT Human Clinical
"The Wissler-Fanconi syndrome is an inflammatory disease of unknown origin, similar to Still's disease, a systemic form of juvenile arthritis."
Establishes that the disease-specific origin was unresolved.
PMID:36090971 SUPPORT Other
"These stimulations on monocytes/macrophages cause activation of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain (NLRP) 3 inflammasomes, which trigger capase-1 activation, resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms."
Defines the AOSD mechanism that remains to be tested in Wissler-labelled patients.
Does the reported co-occurrence of the Wissler-Fanconi pattern with autoimmune polyendocrine syndrome type 1 reflect a shared autoimmune mechanism, or is it a coincidental pairing seen in one patient?
OPEN QUESTION OPEN wissler-aps1-cooccurrence
Attached to
pathophysiology#Recurrent systemic inflammatory episodes
A 1990 case report describes a child with established polyglandular autoimmune syndrome type I who separately met the criteria for Wissler-Fanconi syndrome, and states that this association had not been reported before. Type I polyglandular autoimmune syndrome is a monogenic breakdown of central immune tolerance, so a real association would suggest that the Wissler pattern can arise as a secondary manifestation of a defined immune defect rather than as an independent entity. A single report cannot separate that possibility from chance, and the same report records nine subsequent years without rheumatoid symptoms, so the observation is held here as an open question rather than as an asserted comorbidity.
Proposed experiments
APS-1 cohort screen for the Wissler pattern
aire-cohort-wissler-pattern-screen
Review established APS-1 and AIRE-variant registries for episodes meeting the historical fever, polymorphous exanthem, leukocytosis, and arthralgia pattern, and compare the observed rate with the rate in age-matched autoimmune and general pediatric comparison cohorts.
Readouts
Rate of the Wissler pattern in APS-1 registries versus comparison cohorts
pathophysiology#Recurrent systemic inflammatory episodes
Decision criterion
A rate clearly above the comparison cohorts would support a real association with defective central tolerance; a comparable rate would support coincidence and argue against curating a comorbidity.
Show evidence (2 references)
PMID:2233764 SUPPORT Human Clinical
"All included the criteria of Wissler-Fanconi syndrome became clear which has not yet been reported in association with PGA."
Documents the co-occurrence and states that it was unreported at the time; a single case cannot establish an association.
PMID:2233764 SUPPORT Human Clinical
"Although this syndrome generally is considered an equivalent of Still's syndrome, rheumatoid symptoms could not be ascertained during the following 9-year-course of PGA."
Nine years of follow-up without rheumatoid symptoms in the same patient bears on whether the episode behaved like Still disease.
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Pathophysiology

7
Still-spectrum monocyte and macrophage activation (extrapolated)
Mechanism confidence: Hypothetical
AOSD literature implicates PAMP/DAMP-pattern-recognition-receptor signalling and other stimuli in monocyte/macrophage activation. This is a hypothesis for Wissler-labelled illness only when the Still-spectrum interpretation is accepted; no Wissler-specific cellular study was identified.
Conditional Still-Spectrum Extrapolation
monocyte CL:0000576 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves monocyte (CL:0000576). CL:0000576 is a cell type from the Cell Ontology. macrophage CL:0000235 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves macrophage (CL:0000235). CL:0000235 is a cell type from the Cell Ontology.
pattern recognition receptor signaling pathway GO:0002221 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased pattern recognition receptor signaling pathway (GO:0002221). GO:0002221 is a biological process from the Gene Ontology. ↑ INCREASED inflammatory response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated) In AOSD, the reviewed stimuli activate NLRP3 and caspase-1, producing mature IL-1β and IL-18. Conditional Still-Spectrum Extrapolation
Show evidence (1 reference)
PMID:36090971 SUPPORT Other
"Regarding the activation mechanisms of monocytes/macrophages in AOSD, in addition to type II interferon (IFN) stimulation, several pathways have recently been identified, such as the pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs)-pattern..."
Supports this mechanism in AOSD only; its transfer to Wissler syndrome is conditional on the disputed Still-spectrum hypothesis.
Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
Mechanism confidence: Hypothetical
AOSD studies describe NLRP3 inflammasome activation, caspase-1 activation, and maturation of IL-1β and IL-18 in activated monocytes/macrophages. No corresponding measurement has been reported specifically in a Wissler-syndrome cohort.
Conditional Still-Spectrum Extrapolation
monocyte CL:0000576 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves monocyte (CL:0000576). CL:0000576 is a cell type from the Cell Ontology. macrophage CL:0000235 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves macrophage (CL:0000235). CL:0000235 is a cell type from the Cell Ontology.
NLRP3 inflammasome complex assembly GO:0044546 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased NLRP3 inflammasome complex assembly (GO:0044546). GO:0044546 is a biological process from the Gene Ontology. ↑ INCREASED interleukin-1 beta production GO:0032611 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased interleukin-1 beta production (GO:0032611). GO:0032611 is a biological process from the Gene Ontology. ↑ INCREASED interleukin-18 production GO:0032621 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased interleukin-18 production (GO:0032621). GO:0032621 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Recurrent systemic inflammatory episodes AOSD literature links IL-1β/IL-18 to clinical manifestations, but the causal bridge has not been demonstrated in Wissler-labelled patients. Conditional Still-Spectrum Extrapolation
Show evidence (1 reference)
PMID:36090971 SUPPORT Other
"These stimulations on monocytes/macrophages cause activation of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain (NLRP) 3 inflammasomes, which trigger capase-1 activation, resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms."
Direct evidence for the pathway in AOSD, but only indirect support for a condition whose identity with AOSD is unsettled.
Recurrent systemic inflammatory episodes
Mechanism confidence: Established
The directly observed syndrome is a recurrent inflammatory state marked by fever, polymorphous exanthem, leukocytosis, and arthralgia. The proximal disease-specific molecular cause is unresolved.
inflammatory response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Recurrent high fever Recurrent fever is part of the observed systemic inflammatory state.
Exanthem Polymorphous exanthem is part of the observed systemic inflammatory state.
Arthralgia Arthralgia is part of the observed systemic inflammatory state.
Leukocytosis Leukocytosis is part of the observed systemic inflammatory state.
Arthritis Migratory polyarthritis was observed in a reported case.
Pericardial inflammation Pericardial inflammation can accompany recurrent febrile exacerbations.
Myocardial inflammation Myocardial inflammation can accompany recurrent febrile exacerbations.
Cutaneous small-vessel inflammation The systemic inflammatory syndrome and biopsy-interpreted urticarial vasculitis were observed in the same diagnostically complex case; causal direction and intervening mechanisms are unknown.
Renal microvascular intravascular coagulation A renal biopsy lesion was reported in a patient labelled with incomplete Still's disease or Wissler-Fanconi syndrome, but hematuria was the initial finding; temporal direction, causal direction, and intermediates are unknown.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Defines the directly observed recurrent inflammatory phenotype without asserting an unmeasured molecular cause.
Cutaneous small-vessel inflammation
Mechanism confidence: Provisional
Skin biopsy in one diagnostically complex case was interpreted as urticarial vasculitis. This case observation should not be generalized to every Wissler-associated exanthem.
endothelial cell CL:0000115 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves endothelial cell (CL:0000115). CL:0000115 is a cell type from the Cell Ontology.
inflammatory response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Vasculitis in the skin Histologic cutaneous small-vessel inflammation is the lesion represented by this phenotype.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"A dermatologist biopsied the rash. According to a dermatopathologist, the findings were consistent with urticarial vasculitis."
Direct biopsy evidence from a single case supports a provisional node.
Renal microvascular intravascular coagulation
Mechanism confidence: Provisional
A renal biopsy in a single report of persistent microscopic hematuria was compatible with intravascular coagulation. This rare case-level lesion is not evidence of a universal renal mechanism.
blood coagulation GO:0007596 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased blood coagulation (GO:0007596). GO:0007596 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Microscopic hematuria
Show evidence (1 reference)
PMID:3572917 SUPPORT Human Clinical
"Renal biopsy findings were compatible with intravascular coagulation."
Direct renal-biopsy evidence from one patient supports this provisional node.
Pericardial inflammation
Mechanism confidence: Provisional
Pericarditis, sometimes with an effusion, is a reported cardiac complication. It is separated from myocardial inflammation because the tissues and clinical consequences are distinct.
inflammatory response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Pericarditis Pericardial inflammation is the lesion represented by pericarditis.
Pericardial effusion Pericardial inflammation can produce an effusion.
Show evidence (2 references)
PMID:3092775 SUPPORT Human Clinical
"The long-term evolution is marked by recurrent febrile exacerbations, sometimes complicated by pericardo-myocarditis which usually resolves without sequellae."
Supports pericardial involvement as part of pericardo-myocarditis.
PMID:27843372 SUPPORT Human Clinical
"Computed tomography scan of the chest ruled out pulmonary embolism and revealed a pericardial effusion."
Direct imaging evidence supports pericardial involvement in one case.
Myocardial inflammation
Mechanism confidence: Provisional
Myocarditis is reported within pericardo-myocarditis. One chronic case progressed over seven years to refractory congestive cardiac failure.
inflammatory response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. ↑ INCREASED
Downstream
Myocarditis Myocardial inflammation is the lesion represented by myocarditis.
Congestive heart failure
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The authors report a case with chronic pericardo-myocarditis progressing over a 7 year period to refractory congestive cardiac failure."
Directly supports chronic myocardial involvement and cardiac progression.
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Wissler syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

12
Blood 2
Leukocytosis VERY_FREQUENT Increased total leukocyte count HP:0001974 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Leukocytosis, annotated with Increased total leukocyte count (HP:0001974). HP:0001974 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Leukocytosis is called a typical defining symptom; under the qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
Anemia HP:0001903 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Anemia (HP:0001903). HP:0001903 is a phenotype from the Human Phenotype Ontology.
Mild anemia was documented in one case; its mechanism was not established.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"hemoglobin (9.3 g/dL, normal: 10.1–14.5 g/dL)"
Case-level laboratory data support anemia; frequency and an inflammatory mechanism are not inferred.
Cardiovascular 5
Pericarditis OCCASIONAL HP:0001701 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Pericarditis (HP:0001701). HP:0001701 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The long-term evolution is marked by recurrent febrile exacerbations, sometimes complicated by pericardo-myocarditis which usually resolves without sequellae."
The source says "sometimes," which maps to OCCASIONAL; pericarditis is represented separately from myocarditis.
Myocarditis OCCASIONAL HP:0012819 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Myocarditis (HP:0012819). HP:0012819 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The long-term evolution is marked by recurrent febrile exacerbations, sometimes complicated by pericardo-myocarditis which usually resolves without sequellae."
The source says "sometimes," which maps to OCCASIONAL; myocarditis is represented separately from pericarditis.
Congestive heart failure HP:0001635 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Congestive heart failure (HP:0001635). HP:0001635 is a phenotype from the Human Phenotype Ontology.
Documented as a chronic endpoint in one fatal case.
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The authors report a case with chronic pericardo-myocarditis progressing over a 7 year period to refractory congestive cardiac failure."
A single reported chronic case supports the finding; frequency is omitted because one case does not establish population frequency.
Pericardial effusion HP:0001698 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Pericardial effusion (HP:0001698). HP:0001698 is a phenotype from the Human Phenotype Ontology.
Directly imaged in one diagnostically overlapping case.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Computed tomography scan of the chest ruled out pulmonary embolism and revealed a pericardial effusion."
Direct imaging supports the finding; frequency is omitted because this is a single case.
Vasculitis in the skin HP:0200029 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Urticarial vasculitis, annotated with Vasculitis in the skin (HP:0200029). HP:0200029 is a phenotype from the Human Phenotype Ontology.
Urticarial vasculitis was diagnosed histologically in one case.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"A dermatologist biopsied the rash. According to a dermatopathologist, the findings were consistent with urticarial vasculitis."
Direct biopsy evidence supports the finding; frequency is omitted because this is a single case.
Genitourinary 1
Microscopic hematuria HP:0002907 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Microscopic hematuria (HP:0002907). HP:0002907 is a phenotype from the Human Phenotype Ontology.
Reported as the presenting sign in a single case.
Show evidence (1 reference)
PMID:3572917 SUPPORT Human Clinical
"We describe a case of persistent microscopic hematuria as initial finding in incomplete Still's disease or Wissler-Fanconi syndrome."
An isolated case supports the finding, and its wording also preserves diagnostic uncertainty; frequency is omitted because a single report does not establish population frequency.
Immune 1
Exanthem VERY_FREQUENT HP:4000054 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Exanthem (HP:4000054). HP:4000054 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Polymorphous exanthem is called a typical defining symptom; under the qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
Metabolism 1
Recurrent high fever VERY_FREQUENT Recurrent fever HP:0001954 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Recurrent fever (HP:0001954). HP:0001954 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Recurrent high fever is called a typical defining symptom; under the qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
Musculoskeletal 1
Arthritis HP:0001369 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Arthritis (HP:0001369). HP:0001369 is a phenotype from the Human Phenotype Ontology.
Migratory polyarthritis was reported in a diagnostically overlapping single case.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"The patient had migratory polyarthritis and polymorphic maculopapular rash on the back and lower extremities for 4 months."
Supports arthritis in one case; frequency is omitted because a single report does not establish population frequency.
Constitutional 1
Arthralgia VERY_FREQUENT HP:0002829 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Arthralgia (HP:0002829). HP:0002829 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Arthralgia is called a typical defining symptom; under the qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
💊

Medical Actions

7
Nonsteroidal anti-inflammatory drugs
Action: NSAID therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is NSAID therapy, annotated with Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. Ontology label: Pharmacotherapy NCIT:C15986
Agent: naproxen NCIT:C680 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses naproxen (NCIT:C680). NCIT:C680 is a therapeutic agent from the NCI Thesaurus.
Platform: Small molecule
NSAIDs, including naproxen, have been used in combination regimens for fever, arthralgia, and rash in case reports.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"A combination of naproxen, dapsone, and prednisolone therapy resulted in significant improvement of the patient’s arthralgias and rash."
Supports naproxen as part of a three-drug regimen in a single case; it does not isolate the NSAID effect.
Systemic corticosteroids
Action: corticosteroid agent therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is corticosteroid agent therapy, annotated with Systemic Corticosteroid Therapy (NCIT:C122080). NCIT:C122080 is a clinical intervention from the NCI Thesaurus. Ontology label: Systemic Corticosteroid Therapy NCIT:C122080
Agent: prednisolone NCIT:C769 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses prednisolone (NCIT:C769). NCIT:C769 is a therapeutic agent from the NCI Thesaurus.
Platform: Small molecule
Corticosteroids, including prednisolone, have been used with NSAIDs, dapsone, or azathioprine in case reports; component-specific efficacy is uncertain.
Show evidence (2 references)
PMID:27843372 SUPPORT Human Clinical
"A combination of naproxen, dapsone, and prednisolone therapy resulted in significant improvement of the patient’s arthralgias and rash."
Supports prednisolone only as part of a three-drug regimen in one case.
PMID:1210460 SUPPORT Human Clinical
"In the present case the disease could successfully be controlled using imuran in combination with corticosteroids."
Supports corticosteroids only as part of a combination regimen.
Dapsone
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: dapsone NCIT:C415 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses dapsone (NCIT:C415). NCIT:C415 is a therapeutic agent from the NCI Thesaurus.
Platform: Small molecule
Dapsone was used with naproxen and prednisolone in one reported case.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"A combination of naproxen, dapsone, and prednisolone therapy resulted in significant improvement of the patient’s arthralgias and rash."
Supports dapsone only as part of a three-drug regimen in one case.
Azathioprine
Action: immunosuppressive therapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is immunosuppressive therapy, annotated with Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. Ontology label: Pharmacotherapy NCIT:C15986
Agent: azathioprine NCIT:C290 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses azathioprine (NCIT:C290). NCIT:C290 is a therapeutic agent from the NCI Thesaurus.
Platform: Small molecule
Azathioprine (Imuran) was used with corticosteroids in one adult case.
Show evidence (1 reference)
PMID:1210460 SUPPORT Human Clinical
"In the present case the disease could successfully be controlled using imuran in combination with corticosteroids."
Supports azathioprine only as part of a combination regimen in one case.
Pericardial effusion drainage
Platform: Other
Drainage was used for symptomatic pericardial effusion in one case; it treats the complication rather than the unresolved underlying syndrome.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Shortness of breath and chest pain resulting from pericarditis resolved after the pericardial effusion was drained and the patient was started on dapsone."
Supports drainage plus dapsone in a single case; the contribution of each intervention cannot be separated.
IL-1 inhibition after Still-disease classification (conditional)
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: anakinra NCIT:C38717 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses anakinra (NCIT:C38717). NCIT:C38717 is a therapeutic agent from the NCI Thesaurus. canakinumab NCIT:C80971 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses canakinumab (NCIT:C80971). NCIT:C80971 is a therapeutic agent from the NCI Thesaurus.
Platform: Other
Anakinra or canakinumab may be appropriate when a patient is diagnosed or reclassified as Still disease under contemporary criteria. No Wissler-specific trial was identified, so this is not an evidence-based treatment recommendation for a distinct Wissler entity. The two agents are different biologic platforms: anakinra is a recombinant IL-1 receptor antagonist protein given daily, whereas canakinumab is a long-acting anti-IL-1-beta monoclonal antibody.
Mechanism Target:
INHIBITS Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated) — IL-1 pathway blockade acts downstream of the proposed AOSD inflammasome axis; applicability requires the Still-spectrum hypothesis.
Show evidence (2 references)
PMID:36090971 SUPPORT Other
"Thereafter, IL-1β and IL-18 produced by activated monocytes/macrophages contribute to various clinical features in AOSD."
Supports IL-1 as part of the AOSD axis, not as proven Wissler biology.
PMID:39317417 SUPPORT Other
"The optimal therapeutic strategy relies on early use of interleukin (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid (GC)."
Consensus recommendation supporting IL-1 inhibition in Still disease only. The unbalanced parenthesis is present in the published abstract and is reproduced verbatim.
Show evidence (2 references)
PMID:39317417 SUPPORT Other
"The optimal therapeutic strategy relies on early use of interleukin (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid (GC)."
Consensus supports early IL-1 inhibition in Still disease; transfer to Wissler-labelled illness is conditional on reclassification. The unbalanced parenthesis is present in the published abstract and is reproduced verbatim.
PMID:38302170 SUPPORT Human Clinical
"For bDMARDs, tocilizumab (TCZ), anakinra (ANK), and canakinumab (CNK) had the most available data. Although 3 randomized controlled trials did not show statistically significant benefits of bDMARDs, metaanalyses showed high rates of complete remission and CS discontinuation."
Identifies the AOSD evidence base for anakinra and canakinumab while noting the negative randomized trials; it is not direct evidence for a distinct Wissler entity.
IL-6 inhibition after Still-disease classification (conditional)
Action: PharmacotherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Pharmacotherapy (NCIT:C15986). NCIT:C15986 is a clinical intervention from the NCI Thesaurus. NCIT:C15986
Agent: tocilizumab NCIT:C84217 NCI Thesaurus (NCIT) Relation: this treatment uses this therapeutic agent This treatment uses tocilizumab (NCIT:C84217). NCIT:C84217 is a therapeutic agent from the NCI Thesaurus.
Platform: Monoclonal antibody
Tocilizumab may be appropriate when a patient is diagnosed or reclassified as Still disease. No Wissler-specific trial was identified, and the effect should not be generalized to a distinct historical entity.
Show evidence (2 references)
PMID:39317417 SUPPORT Other
"The optimal therapeutic strategy relies on early use of interleukin (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid (GC)."
Consensus supports early IL-6 inhibition in Still disease; transfer to Wissler-labelled illness is conditional on reclassification. The unbalanced parenthesis is present in the published abstract and is reproduced verbatim.
PMID:38302170 SUPPORT Human Clinical
"For bDMARDs, tocilizumab (TCZ), anakinra (ANK), and canakinumab (CNK) had the most available data. Although 3 randomized controlled trials did not show statistically significant benefits of bDMARDs, metaanalyses showed high rates of complete remission and CS discontinuation."
Identifies the AOSD evidence base for tocilizumab while noting the negative randomized trials; it is not direct evidence for a distinct Wissler entity.
🔬

Biochemical Markers

4
Erythrocyte sedimentation rate (Elevated)
Pathograph Readouts
Readout Of Recurrent systemic inflammatory episodes Positive Diagnostic
Elevated ESR reports systemic inflammation but is not disease-specific.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal: 0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)"
Case data directly document elevated ESR during the inflammatory presentation.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal: 0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)"
Documents markedly elevated ESR in one case.
C-reactive protein (Elevated)
Pathograph Readouts
Readout Of Recurrent systemic inflammatory episodes Positive Diagnostic
Elevated CRP reports systemic inflammation but is not disease-specific.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal: 0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)"
Case data directly document elevated CRP during the inflammatory presentation.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal: 0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)"
Documents markedly elevated CRP in one case.
Hyperferritinemia (Elevated)
Pathograph Readouts
Readout Of Recurrent systemic inflammatory episodes Positive Diagnostic
Elevated ferritin reports inflammatory activity but does not resolve nosology.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Ferritin was significantly high at 29,349 ng/mL (normal: 10–291 ng/mL)."
Directly documents marked hyperferritinemia in one case.
Show evidence (2 references)
PMID:27843372 SUPPORT Human Clinical
"Ferritin was significantly high at 29,349 ng/mL (normal: 10–291 ng/mL)."
Directly documents marked hyperferritinemia in one case.
PMID:41737969 SUPPORT Human Clinical
"Recognition of the Wissler-Fanconi variant and early ferritin testing can prevent diagnostic delay and enable prompt, effective immunosuppressive therapy."
A recent case report emphasizes early ferritin testing in a proposed Wissler-Fanconi/AOSD variant presentation.
Neutrophilic leukocytosis (Elevated)
Pathograph Readouts
Readout Of Recurrent systemic inflammatory episodes Positive Diagnostic
Neutrophilic leukocytosis reports the inflammatory episode after infection is excluded.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"white blood cell count (21,000 cells per µL, >95% neutrophils and 28 bands)"
Directly documents marked neutrophilic leukocytosis in one case.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"white blood cell count (21,000 cells per µL, >95% neutrophils and 28 bands)"
Directly documents marked neutrophilic leukocytosis in one case.
🔬

Diagnosis

3
Historical descriptive clinical pattern
The historical syndrome is recognized by the combination of polymorphous exanthem, recurrent high fever, leukocytosis, and arthralgia. These are descriptive features, not validated classification criteria with known sensitivity or specificity.
Results: The full quartet supports consideration of the historical label.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This rare disease is characterized by four typical symptoms: polymorphous exanthemas, recurrent high fever, leucocytosis and arthralgia."
Defines the historical descriptive pattern.
Exclusionary clinical evaluation
Infection/sepsis, malignancy, and competing autoimmune or autoinflammatory diagnoses must be assessed before applying the historical label. The workup should be tailored to the presentation; no unique confirmatory test exists.
Results: A compatible syndrome after appropriate exclusions may support the label.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude are sepsis/infection, neoplastic diseases (eg, lymphoma), and other autoimmune diseases (eg, Schnitzler-like and dermatomyositis)."
Explicitly describes diagnosis as exclusionary.
Ferritin measurement
Ferritin can quantify hyperferritinemia and may prompt evaluation for AOSD in an overlapping presentation, but it does not confirm Wissler syndrome.
Ferritin Measurement NCIT:C74737 NCI Thesaurus (NCIT)
Results: Marked elevation supports systemic inflammation and Still-disease evaluation.
Show evidence (1 reference)
PMID:41737969 SUPPORT Human Clinical
"Recognition of the Wissler-Fanconi variant and early ferritin testing can prevent diagnostic delay and enable prompt, effective immunosuppressive therapy."
Supports early ferritin testing in a recent AOSD-variant case framing.
📈

Progression

3
Onset and presentation
Age: Childhood to adulthood
Published case reports include pediatric and adult presentations.
Show evidence (3 references)
PMID:2233764 SUPPORT Human Clinical
"A 10.6 year old Turkish girl developed + the signs of a polyglandular autoimmune syndrome (PGA) type I since her first year of age. Apart from the endocrine and non-endocrine symptoms of PGA, she suffered from an acute state of illness with therapy-resistant fever and multiform exanthemas in the..."
Directly documents Wissler-Fanconi features in a pediatric patient.
PMID:8150635 SUPPORT Human Clinical
"A 20-year-old female patient with the typical signs of Wissler's subsepsis allergica (Wissler-Fanconi syndrome) is described."
Documents a young-adult presentation.
PMID:1210460 SUPPORT Human Clinical
"A further case of subsepsis allergica Wissler in a 35-year-old woman is reported."
Documents an adult presentation.
Recurrent course
Recurrent febrile exacerbations characterize the reported long-term course.
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The long-term evolution is marked by recurrent febrile exacerbations, sometimes complicated by pericardo-myocarditis which usually resolves without sequellae."
Directly describes the recurrent course and usual cardiac outcome.
Rare chronic cardiac progression
A single chronic pericardo-myocarditis case progressed to refractory heart failure.
Show evidence (1 reference)
PMID:3092775 SUPPORT Human Clinical
"The authors report a case with chronic pericardo-myocarditis progressing over a 7 year period to refractory congestive cardiac failure."
Supports a rare severe chronic trajectory without implying it is typical.
📊

Prevalence

1
Population not specified
Unknown Rare
Published descriptions call the syndrome rare, but no population-based prevalence estimate was identified.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Wissler-Fanconi syndrome is a rare rheumatic syndrome that was first described during the 1940s in Europe."
Supports a qualitative rare classification while providing no numerical prevalence estimate.
🔀

Differential Diagnoses

8

Conditions with similar clinical presentations that must be differentiated from Wissler syndrome:

Sepsis MONDO:1040015
Overlapping Features Early presentations can resemble septicemia; microbiologic evaluation is essential before assigning a noninfectious historical label.
Distinguishing Features
  • Repeated negative cultures and absence of an infectious focus favor a noninfectious inflammatory syndrome, but do not alone establish Wissler syndrome.
Show evidence (2 references)
PMID:8150635 SUPPORT Human Clinical
"In the early stages it is difficult to differentiate from septicaemia."
Directly identifies septicemia as an early diagnostic mimic.
PMID:27843372 SUPPORT Human Clinical
"Urine and multiple blood cultures were negative."
Documents negative cultures in a case initially suspected to have sepsis.
Acute rheumatic fever Not Yet Curated MONDO:0017767
Overlapping Features Fever, arthritis, and carditis can overlap; contemporary rheumatic-fever criteria and evidence of preceding streptococcal infection should be assessed.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Features of Wissler-Fanconi syndrome can be found in a differential diagnosis that includes true sepsis, acute rheumatic fever, rheumatoid arthritis, and adult onset Still's disease."
Explicitly lists acute rheumatic fever in the differential.
Rheumatoid arthritis MONDO:0008383
Overlapping Features Persistent inflammatory arthritis and rheumatoid serology may support rheumatoid arthritis rather than an isolated historical Wissler syndrome.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Features of Wissler-Fanconi syndrome can be found in a differential diagnosis that includes true sepsis, acute rheumatic fever, rheumatoid arthritis, and adult onset Still's disease."
Explicitly lists rheumatoid arthritis in the differential.
Adult-onset Still's disease MONDO:0019355
Overlapping Features AOSD shares fever, rash, leukocytosis, and arthritis. Whether some or all Wissler-labelled cases are atypical AOSD is unresolved, so this is both a differential diagnosis and the source of a conditional mechanistic model.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"This syndrome was considered by some authors as a premature stage of adult Still’s disease, whereas other authors considered it a separate entity, and this remains open to debate."
Directly documents the unresolved relationship to AOSD.
Systemic-onset juvenile idiopathic arthritis Not Yet Curated MONDO:0019434
Overlapping Features Pediatric Still disease overlaps with the historical pediatric syndrome; established contemporary classification should be applied rather than assuming equivalence from terminology alone.
Show evidence (1 reference)
PMID:8150635 SUPPORT Human Clinical
"This syndrome has sometimes been considered equivalent to or an initial stage of Still's disease (juvenile rheumatoid arthritis) progressing to degenerative arthritis in many patients, whereas other authors have classified it as a separate entity with good prognosis."
Supports the historical pediatric Still overlap while preserving uncertainty.
Lymphoma MONDO:0005062
Overlapping Features Malignancy, particularly lymphoma, should be excluded in a prolonged febrile inflammatory presentation.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude are sepsis/infection, neoplastic diseases (eg, lymphoma), and other autoimmune diseases (eg, Schnitzler-like and dermatomyositis)."
Explicitly names lymphoma among conditions to exclude.
Schnitzler syndrome MONDO:0018304
Overlapping Features A Schnitzler-like autoinflammatory syndrome can overlap through fever and urticarial eruption.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude are sepsis/infection, neoplastic diseases (eg, lymphoma), and other autoimmune diseases (eg, Schnitzler-like and dermatomyositis)."
The source explicitly recommends excluding a Schnitzler-like disorder.
Dermatomyositis MONDO:0016367
Overlapping Features Dermatomyositis is an autoimmune mimic to exclude when inflammatory and cutaneous findings overlap.
Show evidence (1 reference)
PMID:27843372 SUPPORT Human Clinical
"Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude are sepsis/infection, neoplastic diseases (eg, lymphoma), and other autoimmune diseases (eg, Schnitzler-like and dermatomyositis)."
Explicitly names dermatomyositis among conditions to exclude.
{ }

Source YAML

click to show 
name: Wissler syndrome
creation_date: '2026-01-27T22:32:20Z'
category: Immune
description: >-
  Wissler syndrome (Wissler-Fanconi syndrome; historically "subsepsis
  allergica") is a rare descriptive rheumatic syndrome defined by recurrent
  high fever, polymorphous exanthem, leukocytosis, and arthralgia. Its nosologic
  identity remains disputed: publications have treated it as a separate entity,
  an early or atypical Still-disease presentation, or a broad historical label
  spanning several modern diagnoses. No disease-specific molecular mechanism is
  established. Innate-immune mechanisms and biologic treatments established for
  adult-onset Still disease are therefore represented here only as conditional
  extrapolations, not as proven Wissler-syndrome biology or management.
disease_term:
  term:
    id: MONDO:0006018
    label: Wissler syndrome
  preferred_term: Wissler syndrome
parents:
- rheumatic disorder
- syndromic disease
synonyms:
- Wissler-Fanconi syndrome
- Subsepsis allergica
- Subsepsis hyperergica
classifications:
  harrisons_chapter:
  - classification_value: IMMUNE_RHEUMATOLOGIC
    notes: >-
      Placed with the immune-mediated and rheumatologic disorders on the basis
      of its described character as a systemic inflammatory syndrome and its
      disputed relationship to Still disease, not on a settled mechanism.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The Wissler-Fanconi syndrome is an inflammatory disease of unknown
        origin, similar to Still's disease, a systemic form of juvenile
        arthritis.
      explanation: >-
        Characterizes the syndrome as a systemic inflammatory disease related
        to juvenile arthritis, supporting placement in the immune and
        rheumatologic Part.
prevalence:
- population: Population not specified
  measure_type: UNKNOWN
  prevalence_class: RARE
  notes: >-
    Published descriptions call the syndrome rare, but no population-based
    prevalence estimate was identified.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Wissler-Fanconi syndrome is a rare rheumatic syndrome that was first
      described during the 1940s in Europe.
    explanation: >-
      Supports a qualitative rare classification while providing no numerical
      prevalence estimate.
mechanistic_hypotheses:
- hypothesis_group_id: still_spectrum_extrapolation
  hypothesis_label: Conditional Still-Spectrum Extrapolation
  status: ALTERNATIVE
  description: >-
    If a presentation historically labelled Wissler syndrome is an early or
    atypical form of Still disease, AOSD monocyte/macrophage, inflammasome, and
    IL-1/IL-18 mechanisms may apply. This conditional model is supported by
    proposed nosologic overlap, the contemporary consensus that unified the
    Still-disease spectrum, and a recent case-report framing, not by
    Wissler-specific molecular studies.
  evidence:
  - reference: PMID:39317417
    reference_title: EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease.  # codespell:ignore-line
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      sJIA and AOSD are one disease, to be designated by one name, Still's
      disease.
    explanation: >-
      EULAR/PReS consensus unifies systemic juvenile idiopathic arthritis and
      adult-onset Still disease into a single entity, establishing the
      Still-disease spectrum that this hypothesis would extrapolate from. It
      does not place Wissler syndrome inside that spectrum, so the support is
      partial.
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome has sometimes been considered equivalent to or an initial
      stage of Still's disease (juvenile rheumatoid arthritis) progressing to
      degenerative arthritis in many patients, whereas other authors have
      classified it as a separate entity with good prognosis.
    explanation: >-
      Supports historical Still overlap while explicitly documenting a competing
      interpretation.
  - reference: PMID:41737969
    reference_title: "When Fever Defies Diagnosis: Wissler-Fanconi Syndrome as an Atypical Presentation of Adult-Onset Still's Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Recognition of the Wissler-Fanconi variant and early ferritin testing can
      prevent diagnostic delay and enable prompt, effective immunosuppressive
      therapy.
    explanation: >-
      A recent single case report frames Wissler-Fanconi syndrome as an AOSD
      variant; its evidentiary weight is insufficient to settle the nosology.
- hypothesis_group_id: distinct_historical_syndrome
  hypothesis_label: Distinct Historical Syndrome
  status: ALTERNATIVE
  description: >-
    Wissler syndrome may be a separate clinicopathologic entity defined by its
    recurrent febrile-exanthem-leukocytosis-arthralgia pattern. Under this model,
    its cause remains unknown and Still-disease mechanisms cannot be assumed.
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The Wissler-Fanconi syndrome is an inflammatory disease of unknown origin,
      similar to Still's disease, a systemic form of juvenile arthritis.
    explanation: >-
      Describes unknown origin and similarity, rather than demonstrated identity,
      with Still disease.
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome has sometimes been considered equivalent to or an initial
      stage of Still's disease (juvenile rheumatoid arthritis) progressing to
      degenerative arthritis in many patients, whereas other authors have
      classified it as a separate entity with good prognosis.
    explanation: >-
      Directly documents the historical separate-entity interpretation.
pathophysiology:
- name: Still-spectrum monocyte and macrophage activation (extrapolated)
  description: >-
    AOSD literature implicates PAMP/DAMP-pattern-recognition-receptor signalling
    and other stimuli in monocyte/macrophage activation. This is a hypothesis
    for Wissler-labelled illness only when the Still-spectrum interpretation is
    accepted; no Wissler-specific cellular study was identified.
  biological_scale: CELLULAR
  mechanism_confidence: HYPOTHETICAL
  cell_types:
  - preferred_term: monocyte
    term:
      id: CL:0000576
      label: monocyte
  - preferred_term: macrophage
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: pattern recognition receptor signaling pathway
    term:
      id: GO:0002221
      label: pattern recognition receptor signaling pathway
    modifier: INCREASED
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:36090971
    reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      Regarding the activation mechanisms of monocytes/macrophages in AOSD, in
      addition to type II interferon (IFN) stimulation, several pathways have
      recently been identified, such as the pathogen-associated molecular
      patterns (PAMPs) and damage-associated molecular patterns
      (DAMPs)-pattern recognition receptors (PRRs) axis, and neutrophil
      extracellular traps (NETs)-DNA.
    explanation: >-
      Supports this mechanism in AOSD only; its transfer to Wissler syndrome is
      conditional on the disputed Still-spectrum hypothesis.
  downstream:
  - target: Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
    causal_link_type: DIRECT
    description: >-
      In AOSD, the reviewed stimuli activate NLRP3 and caspase-1, producing
      mature IL-1β and IL-18.
    hypothesis_groups:
    - still_spectrum_extrapolation
    evidence:
    - reference: PMID:36090971
      reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        These stimulations on monocytes/macrophages cause activation of the
        nucleotide-binding oligomerization domain, leucine-rich repeat, and
        pyrin domain (NLRP) 3 inflammasomes, which trigger capase-1 activation,
        resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms.
      explanation: >-
        Supports the edge in AOSD; the hypothesis-group tag prevents it from
        being presented as established Wissler-specific causality.
- name: Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
  description: >-
    AOSD studies describe NLRP3 inflammasome activation, caspase-1 activation,
    and maturation of IL-1β and IL-18 in activated monocytes/macrophages. No
    corresponding measurement has been reported specifically in a
    Wissler-syndrome cohort.
  biological_scale: CELLULAR
  mechanism_confidence: HYPOTHETICAL
  cell_types:
  - preferred_term: monocyte
    term:
      id: CL:0000576
      label: monocyte
  - preferred_term: macrophage
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: NLRP3 inflammasome complex assembly
    term:
      id: GO:0044546
      label: NLRP3 inflammasome complex assembly
    modifier: INCREASED
  - preferred_term: interleukin-1 beta production
    term:
      id: GO:0032611
      label: interleukin-1 beta production
    modifier: INCREASED
  - preferred_term: interleukin-18 production
    term:
      id: GO:0032621
      label: interleukin-18 production
    modifier: INCREASED
  evidence:
  - reference: PMID:36090971
    reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      These stimulations on monocytes/macrophages cause activation of the
      nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin
      domain (NLRP) 3 inflammasomes, which trigger capase-1 activation,
      resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms.
    explanation: >-
      Direct evidence for the pathway in AOSD, but only indirect support for a
      condition whose identity with AOSD is unsettled.
  downstream:
  - target: Recurrent systemic inflammatory episodes
    causal_link_type: UNKNOWN
    description: >-
      AOSD literature links IL-1β/IL-18 to clinical manifestations, but the
      causal bridge has not been demonstrated in Wissler-labelled patients.
    hypothesis_groups:
    - still_spectrum_extrapolation
    evidence:
    - reference: PMID:36090971
      reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Thereafter, IL-1β and IL-18 produced by activated monocytes/macrophages
        contribute to various clinical features in AOSD.
      explanation: >-
        Supports an AOSD cytokine-to-clinical link; it remains hypothetical for
        Wissler syndrome.
- name: Recurrent systemic inflammatory episodes
  description: >-
    The directly observed syndrome is a recurrent inflammatory state marked by
    fever, polymorphous exanthem, leukocytosis, and arthralgia. The proximal
    disease-specific molecular cause is unresolved.
  biological_scale: ORGANISM
  mechanism_confidence: ESTABLISHED
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: >-
      Defines the directly observed recurrent inflammatory phenotype without
      asserting an unmeasured molecular cause.
  downstream:
  - target: Recurrent high fever
    causal_link_type: UNKNOWN
    description: Recurrent fever is part of the observed systemic inflammatory state.
    evidence:
    - reference: PMID:8150635
      reference_title: "[Wissler's allergic subsepsis]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This rare disease is characterized by four typical symptoms: polymorphous
        exanthemas, recurrent high fever, leucocytosis and arthralgia.
      explanation: Directly supports fever as a manifestation of the syndrome.
  - target: Exanthem
    causal_link_type: UNKNOWN
    description: Polymorphous exanthem is part of the observed systemic inflammatory state.
    evidence:
    - reference: PMID:8150635
      reference_title: "[Wissler's allergic subsepsis]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This rare disease is characterized by four typical symptoms: polymorphous
        exanthemas, recurrent high fever, leucocytosis and arthralgia.
      explanation: Directly supports exanthem as a manifestation of the syndrome.
  - target: Arthralgia
    causal_link_type: UNKNOWN
    description: Arthralgia is part of the observed systemic inflammatory state.
    evidence:
    - reference: PMID:8150635
      reference_title: "[Wissler's allergic subsepsis]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This rare disease is characterized by four typical symptoms: polymorphous
        exanthemas, recurrent high fever, leucocytosis and arthralgia.
      explanation: Directly supports arthralgia as a manifestation of the syndrome.
  - target: Leukocytosis
    causal_link_type: UNKNOWN
    description: Leukocytosis is part of the observed systemic inflammatory state.
    evidence:
    - reference: PMID:8150635
      reference_title: "[Wissler's allergic subsepsis]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This rare disease is characterized by four typical symptoms: polymorphous
        exanthemas, recurrent high fever, leucocytosis and arthralgia.
      explanation: Directly supports leukocytosis as a manifestation of the syndrome.
  - target: Arthritis
    causal_link_type: UNKNOWN
    description: Migratory polyarthritis was observed in a reported case.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The patient had migratory polyarthritis and polymorphic maculopapular
        rash on the back and lower extremities for 4 months.
      explanation: Case-level evidence supports association but not a molecular mechanism.
  - target: Pericardial inflammation
    causal_link_type: UNKNOWN
    description: Pericardial inflammation can accompany recurrent febrile exacerbations.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The long-term evolution is marked by recurrent febrile exacerbations,
        sometimes complicated by pericardo-myocarditis which usually resolves
        without sequellae.
      explanation: Supports clinical association; causal intermediates remain unknown.
  - target: Myocardial inflammation
    causal_link_type: UNKNOWN
    description: Myocardial inflammation can accompany recurrent febrile exacerbations.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The long-term evolution is marked by recurrent febrile exacerbations,
        sometimes complicated by pericardo-myocarditis which usually resolves
        without sequellae.
      explanation: Supports clinical association; causal intermediates remain unknown.
  - target: Cutaneous small-vessel inflammation
    causal_link_type: UNKNOWN
    description: >-
      The systemic inflammatory syndrome and biopsy-interpreted urticarial
      vasculitis were observed in the same diagnostically complex case; causal
      direction and intervening mechanisms are unknown.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Leukocytosis and polymorphic exanthemous rash persisted. A dermatologist
        biopsied the rash. According to a dermatopathologist, the findings were
        consistent with urticarial vasculitis.
      explanation: >-
        The single case supports co-occurrence of systemic inflammatory features
        and the biopsy finding, not a causal direction or mechanism.
  - target: Renal microvascular intravascular coagulation
    causal_link_type: UNKNOWN
    description: >-
      A renal biopsy lesion was reported in a patient labelled with incomplete
      Still's disease or Wissler-Fanconi syndrome, but hematuria was the initial
      finding; temporal direction, causal direction, and intermediates are unknown.
    evidence:
    - reference: PMID:3572917
      reference_title: Hematuria as presenting sign in Wissler-Fanconi syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We describe a case of persistent microscopic hematuria as initial
        finding in incomplete Still's disease or Wissler-Fanconi syndrome.
        Renal biopsy findings were compatible with intravascular coagulation.
      explanation: >-
        The case supports co-occurrence of the syndrome label, presenting
        hematuria, and biopsy lesion, not that recurrent inflammation preceded
        or caused the renal lesion.
- name: Cutaneous small-vessel inflammation
  description: >-
    Skin biopsy in one diagnostically complex case was interpreted as urticarial
    vasculitis. This case observation should not be generalized to every
    Wissler-associated exanthem.
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  cell_types:
  - preferred_term: endothelial cell
    term:
      id: CL:0000115
      label: endothelial cell
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A dermatologist biopsied the rash. According to a dermatopathologist, the
      findings were consistent with urticarial vasculitis.
    explanation: Direct biopsy evidence from a single case supports a provisional node.
  downstream:
  - target: Vasculitis in the skin
    causal_link_type: DIRECT
    description: Histologic cutaneous small-vessel inflammation is the lesion represented by this phenotype.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        A dermatologist biopsied the rash. According to a dermatopathologist, the
        findings were consistent with urticarial vasculitis.
      explanation: Directly links the biopsy finding to cutaneous vasculitis.
- name: Renal microvascular intravascular coagulation
  description: >-
    A renal biopsy in a single report of persistent microscopic hematuria was
    compatible with intravascular coagulation. This rare case-level lesion is
    not evidence of a universal renal mechanism.
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  biological_processes:
  - preferred_term: blood coagulation
    term:
      id: GO:0007596
      label: blood coagulation
    modifier: INCREASED
  evidence:
  - reference: PMID:3572917
    reference_title: Hematuria as presenting sign in Wissler-Fanconi syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Renal biopsy findings were compatible with intravascular coagulation.
    explanation: Direct renal-biopsy evidence from one patient supports this provisional node.
  downstream:
  - target: Microscopic hematuria
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Renal microvascular injury associated with biopsy-observed intravascular coagulation.
    evidence:
    - reference: PMID:3572917
      reference_title: Hematuria as presenting sign in Wissler-Fanconi syndrome.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We describe a case of persistent microscopic hematuria as initial
        finding in incomplete Still's disease or Wissler-Fanconi syndrome.
        Renal biopsy findings were compatible with intravascular coagulation.
      explanation: The report links hematuria and the biopsy lesion in one patient.
- name: Pericardial inflammation
  description: >-
    Pericarditis, sometimes with an effusion, is a reported cardiac complication.
    It is separated from myocardial inflammation because the tissues and clinical
    consequences are distinct.
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The long-term evolution is marked by recurrent febrile exacerbations,
      sometimes complicated by pericardo-myocarditis which usually resolves
      without sequellae.
    explanation: Supports pericardial involvement as part of pericardo-myocarditis.
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Computed tomography scan of the chest ruled out pulmonary embolism and
      revealed a pericardial effusion.
    explanation: Direct imaging evidence supports pericardial involvement in one case.
  downstream:
  - target: Pericarditis
    causal_link_type: DIRECT
    description: Pericardial inflammation is the lesion represented by pericarditis.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The long-term evolution is marked by recurrent febrile exacerbations,
        sometimes complicated by pericardo-myocarditis which usually resolves
        without sequellae.
      explanation: Directly identifies pericardial inflammation as a complication.
  - target: Pericardial effusion
    causal_link_type: DIRECT
    description: Pericardial inflammation can produce an effusion.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Computed tomography scan of the chest ruled out pulmonary embolism and
        revealed a pericardial effusion.
      explanation: Direct imaging evidence documents the effusion.
- name: Myocardial inflammation
  description: >-
    Myocarditis is reported within pericardo-myocarditis. One chronic case
    progressed over seven years to refractory congestive cardiac failure.
  biological_scale: TISSUE
  mechanism_confidence: PROVISIONAL
  biological_processes:
  - preferred_term: inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The authors report a case with chronic pericardo-myocarditis progressing
      over a 7 year period to refractory congestive cardiac failure.
    explanation: Directly supports chronic myocardial involvement and cardiac progression.
  downstream:
  - target: Myocarditis
    causal_link_type: DIRECT
    description: Myocardial inflammation is the lesion represented by myocarditis.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The authors report a case with chronic pericardo-myocarditis progressing
        over a 7 year period to refractory congestive cardiac failure.
      explanation: Directly documents myocarditis within pericardo-myocarditis.
  - target: Congestive heart failure
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    intermediate_mechanisms:
    - Chronic pericardo-myocarditis with progressive cardiac dysfunction.
    evidence:
    - reference: PMID:3092775
      reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The authors report a case with chronic pericardo-myocarditis progressing
        over a 7 year period to refractory congestive cardiac failure.
      explanation: Directly documents the reported progression to heart failure.
phenotypes:
- name: Recurrent high fever
  category: Systemic
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Recurrent fever
    term:
      id: HP:0001954
      label: Recurrent fever
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: >-
      Recurrent high fever is called a typical defining symptom; under the
      qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
- name: Exanthem
  category: Dermatological
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Exanthem
    term:
      id: HP:4000054
      label: Exanthem
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: >-
      Polymorphous exanthem is called a typical defining symptom; under the
      qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
- name: Arthralgia
  category: Musculoskeletal
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Arthralgia
    term:
      id: HP:0002829
      label: Arthralgia
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: >-
      Arthralgia is called a typical defining symptom; under the
      qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
- name: Leukocytosis
  category: Hematologic
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Leukocytosis
    term:
      id: HP:0001974
      label: Increased total leukocyte count
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: >-
      Leukocytosis is called a typical defining symptom; under the
      qualitative-frequency mapping, "typical" maps to VERY_FREQUENT.
- name: Arthritis
  category: Musculoskeletal
  notes: Migratory polyarthritis was reported in a diagnostically overlapping single case.
  phenotype_term:
    preferred_term: Arthritis
    term:
      id: HP:0001369
      label: Arthritis
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The patient had migratory polyarthritis and polymorphic maculopapular
      rash on the back and lower extremities for 4 months.
    explanation: >-
      Supports arthritis in one case; frequency is omitted because a single
      report does not establish population frequency.
- name: Microscopic hematuria
  category: Renal
  notes: Reported as the presenting sign in a single case.
  phenotype_term:
    preferred_term: Microscopic hematuria
    term:
      id: HP:0002907
      label: Microscopic hematuria
  evidence:
  - reference: PMID:3572917
    reference_title: Hematuria as presenting sign in Wissler-Fanconi syndrome.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We describe a case of persistent microscopic hematuria as initial finding
      in incomplete Still's disease or Wissler-Fanconi syndrome.
    explanation: >-
      An isolated case supports the finding, and its wording also preserves
      diagnostic uncertainty; frequency is omitted because a single report
      does not establish population frequency.
- name: Pericarditis
  category: Cardiovascular
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Pericarditis
    term:
      id: HP:0001701
      label: Pericarditis
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The long-term evolution is marked by recurrent febrile exacerbations,
      sometimes complicated by pericardo-myocarditis which usually resolves
      without sequellae.
    explanation: >-
      The source says "sometimes," which maps to OCCASIONAL; pericarditis is
      represented separately from myocarditis.
- name: Myocarditis
  category: Cardiovascular
  frequency: OCCASIONAL
  phenotype_term:
    preferred_term: Myocarditis
    term:
      id: HP:0012819
      label: Myocarditis
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The long-term evolution is marked by recurrent febrile exacerbations,
      sometimes complicated by pericardo-myocarditis which usually resolves
      without sequellae.
    explanation: >-
      The source says "sometimes," which maps to OCCASIONAL; myocarditis is
      represented separately from pericarditis.
- name: Congestive heart failure
  category: Cardiovascular
  notes: Documented as a chronic endpoint in one fatal case.
  phenotype_term:
    preferred_term: Congestive heart failure
    term:
      id: HP:0001635
      label: Congestive heart failure
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The authors report a case with chronic pericardo-myocarditis progressing
      over a 7 year period to refractory congestive cardiac failure.
    explanation: >-
      A single reported chronic case supports the finding; frequency is omitted
      because one case does not establish population frequency.
- name: Pericardial effusion
  category: Cardiovascular
  notes: Directly imaged in one diagnostically overlapping case.
  phenotype_term:
    preferred_term: Pericardial effusion
    term:
      id: HP:0001698
      label: Pericardial effusion
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Computed tomography scan of the chest ruled out pulmonary embolism and
      revealed a pericardial effusion.
    explanation: >-
      Direct imaging supports the finding; frequency is omitted because this is
      a single case.
- name: Vasculitis in the skin
  category: Dermatological
  notes: Urticarial vasculitis was diagnosed histologically in one case.
  phenotype_term:
    preferred_term: Urticarial vasculitis
    term:
      id: HP:0200029
      label: Vasculitis in the skin
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A dermatologist biopsied the rash. According to a dermatopathologist, the
      findings were consistent with urticarial vasculitis.
    explanation: >-
      Direct biopsy evidence supports the finding; frequency is omitted because
      this is a single case.
- name: Anemia
  category: Hematologic
  notes: Mild anemia was documented in one case; its mechanism was not established.
  phenotype_term:
    preferred_term: Anemia
    term:
      id: HP:0001903
      label: Anemia
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "hemoglobin (9.3 g/dL, normal: 10.1–14.5 g/dL)"
    explanation: >-
      Case-level laboratory data support anemia; frequency and an inflammatory
      mechanism are not inferred.
biochemical:
- name: Erythrocyte sedimentation rate
  presence: Elevated
  biomarker_term:
    preferred_term: Elevated erythrocyte sedimentation rate
    term:
      id: HP:0003565
      label: Elevated erythrocyte sedimentation rate
  readouts:
  - target: Recurrent systemic inflammatory episodes
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated ESR reports systemic inflammation but is not disease-specific.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal:
        0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)
      explanation: Case data directly document elevated ESR during the inflammatory presentation.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal:
      0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)
    explanation: Documents markedly elevated ESR in one case.
- name: C-reactive protein
  presence: Elevated
  biomarker_term:
    preferred_term: Elevated circulating C-reactive protein concentration
    term:
      id: HP:0011227
      label: Elevated circulating C-reactive protein concentration
  readouts:
  - target: Recurrent systemic inflammatory episodes
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated CRP reports systemic inflammation but is not disease-specific.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal:
        0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)
      explanation: Case data directly document elevated CRP during the inflammatory presentation.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Blood sample analysis revealed high levels of CRP (42.9 mg/dL, normal:
      0–0.3), erythrocyte sedimentation rate (113 mm/h normal: 2–20)
    explanation: Documents markedly elevated CRP in one case.
- name: Hyperferritinemia
  presence: Elevated
  notes: >-
    Marked hyperferritinemia has been reported and can prompt consideration of
    Still disease, but it is not a validated Wissler-specific diagnostic criterion.
  biomarker_term:
    preferred_term: Increased circulating ferritin concentration
    term:
      id: HP:0003281
      label: Increased circulating ferritin concentration
  readouts:
  - target: Recurrent systemic inflammatory episodes
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Elevated ferritin reports inflammatory activity but does not resolve nosology.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Ferritin was significantly high at 29,349 ng/mL (normal: 10–291 ng/mL)."
      explanation: Directly documents marked hyperferritinemia in one case.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Ferritin was significantly high at 29,349 ng/mL (normal: 10–291 ng/mL)."
    explanation: Directly documents marked hyperferritinemia in one case.
  - reference: PMID:41737969
    reference_title: "When Fever Defies Diagnosis: Wissler-Fanconi Syndrome as an Atypical Presentation of Adult-Onset Still's Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Recognition of the Wissler-Fanconi variant and early ferritin testing can
      prevent diagnostic delay and enable prompt, effective immunosuppressive therapy.
    explanation: >-
      A recent case report emphasizes early ferritin testing in a proposed
      Wissler-Fanconi/AOSD variant presentation.
- name: Neutrophilic leukocytosis
  presence: Elevated
  notes: Marked neutrophil-predominant leukocytosis with bandemia was reported.
  biomarker_term:
    preferred_term: Increased total neutrophil count
    term:
      id: HP:0011897
      label: Increased total neutrophil count
  readouts:
  - target: Recurrent systemic inflammatory episodes
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: Neutrophilic leukocytosis reports the inflammatory episode after infection is excluded.
    evidence:
    - reference: PMID:27843372
      reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "white blood cell count (21,000 cells per µL, >95% neutrophils and 28 bands)"
      explanation: Directly documents marked neutrophilic leukocytosis in one case.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "white blood cell count (21,000 cells per µL, >95% neutrophils and 28 bands)"
    explanation: Directly documents marked neutrophilic leukocytosis in one case.
progression:
- phase: Onset and presentation
  age_range: Childhood to adulthood
  notes: Published case reports include pediatric and adult presentations.
  evidence:
  - reference: PMID:2233764
    reference_title: "[Subsepsis allergica in a patient with type I polyglandular autoimmune syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A 10.6 year old Turkish girl developed + the signs of a polyglandular
      autoimmune syndrome (PGA) type I since her first year of age. Apart from
      the endocrine and non-endocrine symptoms of PGA, she suffered from an acute
      state of illness with therapy-resistant fever and multiform exanthemas in
      the early course of disease. All included the criteria of Wissler-Fanconi
      syndrome became clear which has not yet been reported in association with PGA.
    explanation: Directly documents Wissler-Fanconi features in a pediatric patient.
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A 20-year-old female patient with the typical signs of Wissler's subsepsis
      allergica (Wissler-Fanconi syndrome) is described.
    explanation: Documents a young-adult presentation.
  - reference: PMID:1210460
    reference_title: "[A further case of Wissler's allergic subsepticemia in an adult]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A further case of subsepsis allergica Wissler in a 35-year-old woman is reported.
    explanation: Documents an adult presentation.
- phase: Recurrent course
  notes: Recurrent febrile exacerbations characterize the reported long-term course.
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The long-term evolution is marked by recurrent febrile exacerbations,
      sometimes complicated by pericardo-myocarditis which usually resolves
      without sequellae.
    explanation: Directly describes the recurrent course and usual cardiac outcome.
- phase: Rare chronic cardiac progression
  notes: A single chronic pericardo-myocarditis case progressed to refractory heart failure.
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The authors report a case with chronic pericardo-myocarditis progressing
      over a 7 year period to refractory congestive cardiac failure.
    explanation: Supports a rare severe chronic trajectory without implying it is typical.
diagnosis:
- name: Historical descriptive clinical pattern
  description: >-
    The historical syndrome is recognized by the combination of polymorphous
    exanthem, recurrent high fever, leukocytosis, and arthralgia. These are
    descriptive features, not validated classification criteria with known
    sensitivity or specificity.
  results: The full quartet supports consideration of the historical label.
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This rare disease is characterized by four typical symptoms: polymorphous
      exanthemas, recurrent high fever, leucocytosis and arthralgia.
    explanation: Defines the historical descriptive pattern.
- name: Exclusionary clinical evaluation
  description: >-
    Infection/sepsis, malignancy, and competing autoimmune or autoinflammatory
    diagnoses must be assessed before applying the historical label. The workup
    should be tailored to the presentation; no unique confirmatory test exists.
  results: A compatible syndrome after appropriate exclusions may support the label.
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude
      are sepsis/infection, neoplastic diseases (eg, lymphoma), and other
      autoimmune diseases (eg, Schnitzler-like and dermatomyositis).
    explanation: Explicitly describes diagnosis as exclusionary.
- name: Ferritin measurement
  diagnosis_term:
    preferred_term: Ferritin Measurement
    term:
      id: NCIT:C74737
      label: Ferritin Measurement
  description: >-
    Ferritin can quantify hyperferritinemia and may prompt evaluation for AOSD
    in an overlapping presentation, but it does not confirm Wissler syndrome.
  results: Marked elevation supports systemic inflammation and Still-disease evaluation.
  evidence:
  - reference: PMID:41737969
    reference_title: "When Fever Defies Diagnosis: Wissler-Fanconi Syndrome as an Atypical Presentation of Adult-Onset Still's Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Recognition of the Wissler-Fanconi variant and early ferritin testing can
      prevent diagnostic delay and enable prompt, effective immunosuppressive therapy.
    explanation: Supports early ferritin testing in a recent AOSD-variant case framing.
notes: >-
  Wissler-Fanconi syndrome was first described in Europe in the 1940s, and most
  of the literature since then is in French and German. As of the 2016 case
  report cited in this entry (PMID:27843372), only a very few papers had
  appeared in English, none of them recent. That publication-language skew is
  why the entity is under-represented in English-language sources, and why
  several references cited here are not in English.
differential_diagnoses:
- name: Sepsis
  description: >-
    Early presentations can resemble septicemia; microbiologic evaluation is
    essential before assigning a noninfectious historical label.
  distinguishing_features:
  - Repeated negative cultures and absence of an infectious focus favor a noninfectious inflammatory syndrome, but do not alone establish Wissler syndrome.
  disease_term:
    preferred_term: infectious disease with sepsis
    term:
      id: MONDO:1040015
      label: infectious disease with sepsis
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: In the early stages it is difficult to differentiate from septicaemia.
    explanation: Directly identifies septicemia as an early diagnostic mimic.
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Urine and multiple blood cultures were negative.
    explanation: Documents negative cultures in a case initially suspected to have sepsis.
- name: Acute rheumatic fever
  description: >-
    Fever, arthritis, and carditis can overlap; contemporary rheumatic-fever
    criteria and evidence of preceding streptococcal infection should be assessed.
  disease_term:
    preferred_term: rheumatic fever
    term:
      id: MONDO:0017767
      label: rheumatic fever
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Features of Wissler-Fanconi syndrome can be found in a differential
      diagnosis that includes true sepsis, acute rheumatic fever, rheumatoid
      arthritis, and adult onset Still's disease.
    explanation: Explicitly lists acute rheumatic fever in the differential.
- name: Rheumatoid arthritis
  description: >-
    Persistent inflammatory arthritis and rheumatoid serology may support
    rheumatoid arthritis rather than an isolated historical Wissler syndrome.
  disease_term:
    preferred_term: rheumatoid arthritis
    term:
      id: MONDO:0008383
      label: rheumatoid arthritis
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Features of Wissler-Fanconi syndrome can be found in a differential
      diagnosis that includes true sepsis, acute rheumatic fever, rheumatoid
      arthritis, and adult onset Still's disease.
    explanation: Explicitly lists rheumatoid arthritis in the differential.
- name: Adult-onset Still's disease
  description: >-
    AOSD shares fever, rash, leukocytosis, and arthritis. Whether some or all
    Wissler-labelled cases are atypical AOSD is unresolved, so this is both a
    differential diagnosis and the source of a conditional mechanistic model.
  disease_term:
    preferred_term: adult-onset Still disease
    term:
      id: MONDO:0019355
      label: adult-onset Still disease
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome was considered by some authors as a premature stage of adult
      Still’s disease, whereas other authors considered it a separate entity,
      and this remains open to debate.
    explanation: Directly documents the unresolved relationship to AOSD.
- name: Systemic-onset juvenile idiopathic arthritis
  description: >-
    Pediatric Still disease overlaps with the historical pediatric syndrome;
    established contemporary classification should be applied rather than
    assuming equivalence from terminology alone.
  disease_term:
    preferred_term: systemic-onset juvenile idiopathic arthritis
    term:
      id: MONDO:0019434
      label: systemic-onset juvenile idiopathic arthritis
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome has sometimes been considered equivalent to or an initial
      stage of Still's disease (juvenile rheumatoid arthritis) progressing to
      degenerative arthritis in many patients, whereas other authors have
      classified it as a separate entity with good prognosis.
    explanation: Supports the historical pediatric Still overlap while preserving uncertainty.
- name: Lymphoma
  description: Malignancy, particularly lymphoma, should be excluded in a prolonged febrile inflammatory presentation.
  disease_term:
    preferred_term: lymphoma
    term:
      id: MONDO:0005062
      label: lymphoma
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude
      are sepsis/infection, neoplastic diseases (eg, lymphoma), and other
      autoimmune diseases (eg, Schnitzler-like and dermatomyositis).
    explanation: Explicitly names lymphoma among conditions to exclude.
- name: Schnitzler syndrome
  description: A Schnitzler-like autoinflammatory syndrome can overlap through fever and urticarial eruption.
  disease_term:
    preferred_term: Schnitzler syndrome
    term:
      id: MONDO:0018304
      label: Schnitzler syndrome
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude
      are sepsis/infection, neoplastic diseases (eg, lymphoma), and other
      autoimmune diseases (eg, Schnitzler-like and dermatomyositis).
    explanation: The source explicitly recommends excluding a Schnitzler-like disorder.
- name: Dermatomyositis
  description: Dermatomyositis is an autoimmune mimic to exclude when inflammatory and cutaneous findings overlap.
  disease_term:
    preferred_term: dermatomyositis
    term:
      id: MONDO:0016367
      label: dermatomyositis
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Before diagnosing Wissler-Fanconi syndrome, other conditions to exclude
      are sepsis/infection, neoplastic diseases (eg, lymphoma), and other
      autoimmune diseases (eg, Schnitzler-like and dermatomyositis).
    explanation: Explicitly names dermatomyositis among conditions to exclude.
treatments:
- name: Nonsteroidal anti-inflammatory drugs
  description: >-
    NSAIDs, including naproxen, have been used in combination regimens for
    fever, arthralgia, and rash in case reports.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: NSAID therapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: naproxen
      term:
        id: NCIT:C680
        label: Naproxen
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A combination of naproxen, dapsone, and prednisolone therapy resulted in
      significant improvement of the patient’s arthralgias and rash.
    explanation: >-
      Supports naproxen as part of a three-drug regimen in a single case; it does
      not isolate the NSAID effect.
- name: Systemic corticosteroids
  description: >-
    Corticosteroids, including prednisolone, have been used with NSAIDs,
    dapsone, or azathioprine in case reports; component-specific efficacy is
    uncertain.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: corticosteroid agent therapy
    term:
      id: NCIT:C122080
      label: Systemic Corticosteroid Therapy
    therapeutic_agent:
    - preferred_term: prednisolone
      term:
        id: NCIT:C769
        label: Prednisolone
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A combination of naproxen, dapsone, and prednisolone therapy resulted in
      significant improvement of the patient’s arthralgias and rash.
    explanation: Supports prednisolone only as part of a three-drug regimen in one case.
  - reference: PMID:1210460
    reference_title: "[A further case of Wissler's allergic subsepticemia in an adult]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In the present case the disease could successfully be controlled using
      imuran in combination with corticosteroids.
    explanation: Supports corticosteroids only as part of a combination regimen.
- name: Dapsone
  description: Dapsone was used with naproxen and prednisolone in one reported case.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: dapsone
      term:
        id: NCIT:C415
        label: Dapsone
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A combination of naproxen, dapsone, and prednisolone therapy resulted in
      significant improvement of the patient’s arthralgias and rash.
    explanation: Supports dapsone only as part of a three-drug regimen in one case.
- name: Azathioprine
  description: Azathioprine (Imuran) was used with corticosteroids in one adult case.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: immunosuppressive therapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: azathioprine
      term:
        id: NCIT:C290
        label: Azathioprine
  evidence:
  - reference: PMID:1210460
    reference_title: "[A further case of Wissler's allergic subsepticemia in an adult]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In the present case the disease could successfully be controlled using
      imuran in combination with corticosteroids.
    explanation: Supports azathioprine only as part of a combination regimen in one case.
- name: Pericardial effusion drainage
  description: >-
    Drainage was used for symptomatic pericardial effusion in one case; it treats
    the complication rather than the unresolved underlying syndrome.
  therapeutic_modality: OTHER
  evidence:
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Shortness of breath and chest pain resulting from pericarditis resolved
      after the pericardial effusion was drained and the patient was started on dapsone.
    explanation: >-
      Supports drainage plus dapsone in a single case; the contribution of each
      intervention cannot be separated.
- name: IL-1 inhibition after Still-disease classification (conditional)
  description: >-
    Anakinra or canakinumab may be appropriate when a patient is diagnosed or
    reclassified as Still disease under contemporary criteria. No
    Wissler-specific trial was identified, so this is not an evidence-based
    treatment recommendation for a distinct Wissler entity. The two agents are
    different biologic platforms: anakinra is a recombinant IL-1 receptor
    antagonist protein given daily, whereas canakinumab is a long-acting
    anti-IL-1-beta monoclonal antibody.
  therapeutic_modality: OTHER
  notes: >-
    Modality is recorded as OTHER because this entry covers IL-1 pathway
    blockade as a strategy rather than a single agent, and its two agents fall
    under different platforms (recombinant receptor-antagonist protein versus
    monoclonal antibody). No enum value covers both, and the slot is
    single-valued, so neither SMALL_MOLECULE nor MONOCLONAL_ANTIBODY would be
    accurate for the pair.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: anakinra
      term:
        id: NCIT:C38717
        label: Anakinra
    - preferred_term: canakinumab
      term:
        id: NCIT:C80971
        label: Canakinumab
  target_mechanisms:
  - target: Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
    treatment_effect: INHIBITS
    description: >-
      IL-1 pathway blockade acts downstream of the proposed AOSD inflammasome
      axis; applicability requires the Still-spectrum hypothesis.
    evidence:
    - reference: PMID:36090971
      reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        Thereafter, IL-1β and IL-18 produced by activated monocytes/macrophages
        contribute to various clinical features in AOSD.
      explanation: Supports IL-1 as part of the AOSD axis, not as proven Wissler biology.
    - reference: PMID:39317417
      reference_title: EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease.  # codespell:ignore-line
      supports: SUPPORT
      evidence_source: OTHER
      snippet: >-
        The optimal therapeutic strategy relies on early use of interleukin
        (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid
        (GC).
      explanation: >-
        Consensus recommendation supporting IL-1 inhibition in Still disease
        only. The unbalanced parenthesis is present in the published abstract
        and is reproduced verbatim.
  evidence:
  - reference: PMID:39317417
    reference_title: EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease.  # codespell:ignore-line
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The optimal therapeutic strategy relies on early use of interleukin
      (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid
      (GC).
    explanation: >-
      Consensus supports early IL-1 inhibition in Still disease; transfer to
      Wissler-labelled illness is conditional on reclassification. The
      unbalanced parenthesis is present in the published abstract and is
      reproduced verbatim.
  - reference: PMID:38302170
    reference_title: Systematic Review and Metaanalysis of Pharmacological Interventions in Adult-Onset Still Disease and the Role of Biologic Disease-Modifying Antirheumatic Drugs.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      For bDMARDs, tocilizumab (TCZ), anakinra (ANK), and canakinumab (CNK) had
      the most available data. Although 3 randomized controlled trials did not
      show statistically significant benefits of bDMARDs, metaanalyses showed
      high rates of complete remission and CS discontinuation.
    explanation: >-
      Identifies the AOSD evidence base for anakinra and canakinumab while noting
      the negative randomized trials; it is not direct evidence for a distinct
      Wissler entity.
- name: IL-6 inhibition after Still-disease classification (conditional)
  description: >-
    Tocilizumab may be appropriate when a patient is diagnosed or reclassified
    as Still disease. No Wissler-specific trial was identified, and the effect
    should not be generalized to a distinct historical entity.
  therapeutic_modality: MONOCLONAL_ANTIBODY
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: tocilizumab
      term:
        id: NCIT:C84217
        label: Tocilizumab
  evidence:
  - reference: PMID:39317417
    reference_title: EULAR/PReS recommendations for the diagnosis and management of Still's disease, comprising systemic juvenile idiopathic arthritis and adult-onset Still's disease.  # codespell:ignore-line
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      The optimal therapeutic strategy relies on early use of interleukin
      (IL-1 or IL-6 inhibitors associated to short duration glucocorticoid
      (GC).
    explanation: >-
      Consensus supports early IL-6 inhibition in Still disease; transfer to
      Wissler-labelled illness is conditional on reclassification. The
      unbalanced parenthesis is present in the published abstract and is
      reproduced verbatim.
  - reference: PMID:38302170
    reference_title: Systematic Review and Metaanalysis of Pharmacological Interventions in Adult-Onset Still Disease and the Role of Biologic Disease-Modifying Antirheumatic Drugs.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      For bDMARDs, tocilizumab (TCZ), anakinra (ANK), and canakinumab (CNK) had
      the most available data. Although 3 randomized controlled trials did not
      show statistically significant benefits of bDMARDs, metaanalyses showed
      high rates of complete remission and CS discontinuation.
    explanation: >-
      Identifies the AOSD evidence base for tocilizumab while noting the negative
      randomized trials; it is not direct evidence for a distinct Wissler entity.
datasets: []
discussions:
- discussion_id: wissler-nosologic-boundary
  kind: CONTROVERSY
  status: OPEN
  attaches_to:
  - mechanistic_hypotheses#still_spectrum_extrapolation
  - mechanistic_hypotheses#distinct_historical_syndrome
  - diagnosis#Historical descriptive clinical pattern
  prompt: >-
    Is Wissler syndrome a distinct entity, an early or atypical Still-disease
    presentation, or a historical umbrella that combines several modern diagnoses?
  rationale: >-
    The literature explicitly presents competing interpretations. A 1994 report
    records both equivalence/initial-stage and separate-entity views; a 2016 case
    report says the boundary remains open to debate; a 2026 case report uses a
    Still-variant framing but cannot settle the issue alone. The answer controls
    whether AOSD mechanism and treatment evidence can be transferred.
  evidence:
  - reference: PMID:8150635
    reference_title: "[Wissler's allergic subsepsis]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome has sometimes been considered equivalent to or an initial
      stage of Still's disease (juvenile rheumatoid arthritis) progressing to
      degenerative arthritis in many patients, whereas other authors have
      classified it as a separate entity with good prognosis.
    explanation: Explicitly documents the two competing historical interpretations.
  - reference: PMID:27843372
    reference_title: "Wissler-Fanconi syndrome and related diagnoses: a case report."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This syndrome was considered by some authors as a premature stage of adult
      Still’s disease, whereas other authors considered it a separate entity,
      and this remains open to debate.
    explanation: Explicitly states that the nosologic boundary remains unresolved.
  - reference: PMID:41737969
    reference_title: "When Fever Defies Diagnosis: Wissler-Fanconi Syndrome as an Atypical Presentation of Adult-Onset Still's Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Recognition of the Wissler-Fanconi variant and early ferritin testing can
      prevent diagnostic delay and enable prompt, effective immunosuppressive therapy.
    explanation: Provides a recent, but single-case, Still-variant interpretation.
  proposed_experiments:
  - experiment_id: prospective-wissler-nosology-cohort
    name: Prospective multicenter nosology cohort
    description: >-
      Enroll patients meeting the historical
      fever-exanthem-leukocytosis-arthralgia pattern before final diagnosis.
      Apply standardized infectious,
      malignant, rheumatic-fever, rheumatoid-arthritis, systemic-JIA, and AOSD
      evaluations; collect longitudinal phenotypes, serial cytokines, ferritin,
      and single-cell immune profiles; and adjudicate final diagnoses blinded to
      molecular clustering.
    readouts:
    - name: Concordance of historical phenotype with contemporary diagnosis and immune cluster
      target: pathophysiology#Recurrent systemic inflammatory episodes
    decision_criterion: >-
      A reproducible cluster that aligns with contemporary Still disease would
      support transfer of Still mechanisms; a distinct reproducible cluster
      would support a separate entity; heterogeneous final diagnoses without a
      shared profile would support an umbrella-label interpretation.
- discussion_id: wissler-mechanism-validation
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Still-spectrum monocyte and macrophage activation (extrapolated)
  - pathophysiology#Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
  prompt: >-
    Do patients prospectively identified by the historical Wissler pattern show
    the monocyte/macrophage and NLRP3-IL-1/IL-18 state described in AOSD?
  rationale: >-
    The mechanistic evidence currently comes from AOSD, and no disease-specific
    experimental model, cohort-scale cytokine study, or omics dataset was
    identified. Importing an AOSD model would assume the disputed equivalence.
  evidence:
  - reference: PMID:3092775
    reference_title: "[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The Wissler-Fanconi syndrome is an inflammatory disease of unknown origin,
      similar to Still's disease, a systemic form of juvenile arthritis.
    explanation: Establishes that the disease-specific origin was unresolved.
  - reference: PMID:36090971
    reference_title: Activation mechanisms of monocytes/macrophages in adult-onset Still disease.
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      These stimulations on monocytes/macrophages cause activation of the
      nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin
      domain (NLRP) 3 inflammasomes, which trigger capase-1 activation,
      resulting in conversion of pro-IL-1β and pro-IL-18 into mature forms.
    explanation: Defines the AOSD mechanism that remains to be tested in Wissler-labelled patients.
  proposed_experiments:
  - experiment_id: wissler-aosed-mechanism-comparison
    name: Blinded Wissler-pattern versus AOSD immune comparison
    description: >-
      Compare prospectively collected Wissler-pattern cases, criteria-confirmed
      AOSD/systemic JIA, febrile infectious controls, and inflammatory controls
      using serial monocyte activation phenotyping, inflammasome activity,
      IL-1β/IL-18 measurements, and single-cell transcriptomics before major
      immunosuppression.
    readouts:
    - name: Reproducible monocyte and inflammasome signature by adjudicated diagnosis
      target: pathophysiology#Still-spectrum NLRP3 and IL-1/IL-18 activation (extrapolated)
    decision_criterion: >-
      A replicated signature matching Still disease after exclusion of mimics
      would support the conditional mechanism; absence of that signature or
      separation into heterogeneous disease-specific profiles would refute its
      use as a general Wissler mechanism.
- discussion_id: wissler-aps1-cooccurrence
  kind: OPEN_QUESTION
  status: OPEN
  attaches_to:
  - pathophysiology#Recurrent systemic inflammatory episodes
  prompt: >-
    Does the reported co-occurrence of the Wissler-Fanconi pattern with
    autoimmune polyendocrine syndrome type 1 reflect a shared autoimmune
    mechanism, or is it a coincidental pairing seen in one patient?
  rationale: >-
    A 1990 case report describes a child with established polyglandular
    autoimmune syndrome type I who separately met the criteria for
    Wissler-Fanconi syndrome, and states that this association had not been
    reported before. Type I polyglandular autoimmune syndrome is a monogenic
    breakdown of central immune tolerance, so a real association would suggest
    that the Wissler pattern can arise as a secondary manifestation of a
    defined immune defect rather than as an independent entity. A single report
    cannot separate that possibility from chance, and the same report records
    nine subsequent years without rheumatoid symptoms, so the observation is
    held here as an open question rather than as an asserted comorbidity.
  evidence:
  - reference: PMID:2233764
    reference_title: "[Subsepsis allergica in a patient with type I polyglandular autoimmune syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      All included the criteria of Wissler-Fanconi syndrome became clear which
      has not yet been reported in association with PGA.
    explanation: >-
      Documents the co-occurrence and states that it was unreported at the
      time; a single case cannot establish an association.
  - reference: PMID:2233764
    reference_title: "[Subsepsis allergica in a patient with type I polyglandular autoimmune syndrome]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Although this syndrome generally is considered an equivalent of Still's
      syndrome, rheumatoid symptoms could not be ascertained during the
      following 9-year-course of PGA.
    explanation: >-
      Nine years of follow-up without rheumatoid symptoms in the same patient
      bears on whether the episode behaved like Still disease.
  proposed_experiments:
  - experiment_id: aire-cohort-wissler-pattern-screen
    name: APS-1 cohort screen for the Wissler pattern
    description: >-
      Review established APS-1 and AIRE-variant registries for episodes meeting
      the historical fever, polymorphous exanthem, leukocytosis, and arthralgia
      pattern, and compare the observed rate with the rate in age-matched
      autoimmune and general pediatric comparison cohorts.
    readouts:
    - name: Rate of the Wissler pattern in APS-1 registries versus comparison cohorts
      target: pathophysiology#Recurrent systemic inflammatory episodes
    decision_criterion: >-
      A rate clearly above the comparison cohorts would support a real
      association with defective central tolerance; a comparable rate would
      support coincidence and argue against curating a comorbidity.