Eosinophilic Fasciitis

1. Disease Information

Overview. Eosinophilic fasciitis (EF) is a rare, acquired, sclerosing/fibrosing connective-tissue disorder marked by acute-to-subacute inflammation and progressive thickening (fibrosis) of the deep muscular fascia and overlying subcutis, classically of the limbs. It presents with symmetric edema, erythema and induration of the extremities, evolving into a woody "peau d'orange" (orange-peel) skin texture and a pathognomonic "groove sign" (linear depressions along the course of superficial veins, accentuated by limb elevation). It is accompanied in most patients by peripheral blood eosinophilia, polyclonal hypergammaglobulinemia, and elevated inflammatory markers (ESR/CRP). EF is widely regarded as a scleroderma-like / scleroderma-spectrum disease, but is distinguished from systemic sclerosis by sparing of the fingers and face, absence of Raynaud phenomenon, absence of nailfold capillary changes, and lack of visceral organ involvement (Mazilu et al. 2023, Int J Mol Sci, PMID:36768300; original description Shulman 1974).

Key identifiers. - MONDO: MONDO:0009175 (eosinophilic fasciitis) — verified against the local MONDO adapter. - Orphanet: ORPHA:3165 (flag for verification; Orphanet page was behind a bot-check at fetch time). - ICD-10: M35.4 (Diffuse [eosinophilic] fasciitis). - ICD-11: 4A43.0 (Eosinophilic fasciitis), under "Diseases of the immune system with predominant connective-tissue involvement." - MeSH: D005159 "Fasciitis" / EF appears as "Eosinophilic Fasciitis" (Shulman syndrome). - OMIM: None — EF has no OMIM Mendelian entry (not a single-gene disorder).

Synonyms / alternative names: Shulman syndrome; Shulman disease; diffuse fasciitis with eosinophilia; diffuse eosinophilic fasciitis; eosinophilic fasciitis with eosinophilia.

Data provenance. Knowledge is derived almost entirely from aggregated disease-level resources and case series/case reports (EF is too rare for large registries). There is no large EHR cohort; the literature is dominated by single-center series (e.g., a 52-patient Mayo Clinic cohort) and systematic reviews of pooled case reports.

2. Etiology

Causal factors. EF is idiopathic in the majority of cases. It is best understood as an immune-mediated fibrosing reaction to a triggering insult in a susceptible host, not a genetic disease. Recognized/proposed triggers (each from case reports/series; association ≠ proven causation):

• Strenuous/unaccustomed physical exertion or trauma — the single most frequently cited antecedent; reported in ~30–50% of cases preceding onset (Mazilu et al. 2023, PMID:36768300: "Sustained intense physical exercise" is the most prominent trigger).
• Drugs: statins (notably simvastatin/atorvastatin), phenytoin, ramipril, subcutaneous heparin, and — increasingly important — immune checkpoint inhibitors (ICIs) (anti–PD-1/PD-L1 pembrolizumab, nivolumab; anti–CTLA-4 ipilimumab) (PMID:40399177, 2025 review of 30 ICI-EF cases; PMID:32127188 nivolumab-triggered EF).
• Infections / immune triggers: Borrelia burgdorferi (controversial), and recently SARS-CoV-2 (COVID-19) and COVID vaccination (PMID:38292575, EF following COVID-19 case series).
• Toxic exposures: historically L-tryptophan (eosinophilia–myalgia syndrome) and toxic-oil syndrome are EF-like but are distinct toxic entities; trichloroethylene and other organic solvents have been implicated.
• Hematologic / neoplastic association: EF can be paraneoplastic, associated with hematologic disorders (see §9).

Genetic risk factors. No established Mendelian gene, GWAS locus, or validated susceptibility allele. Rare familial clustering and isolated HLA associations have been suggested but are not established. No ClinVar/ClinGen/GWAS-Catalog entries are applicable.

Environmental risk factors. Vigorous exercise/trauma, the drug exposures above, and (debated) infectious triggers. Age (peak 30–60 y) and possibly male sex in ICI-related disease are demographic risk modifiers.

Protective factors. None established (no genetic protective variant or dietary/lifestyle protective factor is documented for this rare disease).

Gene–environment interactions. Not characterized. The plausible model is that an environmental/immune trigger (exercise, drug, checkpoint blockade) drives a Th2/eosinophil-skewed, profibrotic fascial response in a host of undefined predisposition; no specific GxE data exist (CTD/PheGenI have no EF-specific entries).

3. Phenotypes

Suggested HPO terms in brackets; frequencies are qualitative pooled estimates from case series — treat frequency bands as needing their own evidence per the dismech frequency SOP.

Cutaneous / fascial (the core phenotype): - Symmetric skin induration / "woody" thickening of extremities — near-universal; forearms and lower legs most affected, typically sparing hands/feet and face. [HP:0007543 "Subcutaneous tissue induration"? or HP:0100679 "Localized skin lesion"; best fit HP:0100683 not ideal — consider HP:0001075 "Abnormal skin morphology" plus a descriptive preferred_term; HP:0011924 "Abnormal skin morphology" family]. Onset: adult; course: progressive. - "Peau d'orange" / orange-peel skin texture — characteristic; FREQUENT. - "Groove sign" (depression along superficial veins on limb elevation) — fairly specific, OCCASIONAL–FREQUENT. - Erythema and edema of limbs (early, inflammatory phase) — FREQUENT. [HP:0000964 "Eczema"? no — use HP:0100749 "Chest pain"? no; for edema HP:0000969 "Edema"]. - Pruritus — OCCASIONAL. [HP:0000989 "Pruritus"]. - Morphea-like plaques / overlap with morphea — ~29–40% of EF patients have concurrent morphea (PMID:36768300). [HP:0100698 "Morphea"? use HP:0100699 "Scleroderma" family].

Musculoskeletal: - Joint contractures (especially elbows, wrists, knees, ankles) — common and a major cause of disability; can require surgery. [HP:0001371 "Flexion contracture"]. Course: progressive. - Arthritis / inflammatory arthritis — "present in less than half the patients" (PMID:36768300). [HP:0001369 "Arthritis"]. - Myalgia — present but "much less common and much milder" than in eosinophilia–myalgia syndrome (PMID:36768300). [HP:0003326 "Myalgia"]. - Carpal tunnel syndrome — from fascial compression at the wrist; OCCASIONAL. [HP:0012185 "Carpal tunnel syndrome"]. - Limited joint mobility / reduced range of motion — FREQUENT. [HP:0001376 "Limitation of joint mobility"].

Laboratory abnormalities: - Peripheral blood eosinophilia — present in ~60–90% (transient, often early, and not correlated with disease severity; PMID:36768300). [HP:0001880 "Eosinophilia"]. - Polyclonal hypergammaglobulinemia — FREQUENT. [HP:0003237 "Increased circulating IgG level" / HP:0010701 "Abnormal immunoglobulin level"]. - Elevated ESR / CRP — FREQUENT. [HP:0003565 "Elevated erythrocyte sedimentation rate"; HP:0011227 "Elevated C-reactive protein level"]. - Elevated serum aldolase (with often-normal CK) — a useful marker of fascial/muscle inflammation; OCCASIONAL–FREQUENT. [HP:0008331 "Elevated aldolase"? → use HP:0003236 "Elevated circulating creatine kinase" family / aldolase has no precise HP]. - TARC/CCL17 elevation, IL-5 elevation — research biomarkers (see §6).

Systemic / general: constitutional symptoms (fatigue, low-grade fever, weight loss) are usually mild; visceral organ involvement is characteristically ABSENT, which is a key diagnostic discriminator from systemic sclerosis.

Quality-of-life impact. Driven mainly by joint contractures and limb stiffness → impaired hand function, gait, dressing, and activities of daily living; chronic refractory disease and contractures are the principal QoL detractors. No EF-specific EQ-5D/SF-36 dataset exists; impact is inferred from functional-outcome reporting in case series.

4. Genetic / Molecular Information

• Causal genes: None. EF is a non-Mendelian, acquired immune-fibrotic disease; there is no causal gene, pathogenic variant, modifier gene, founder mutation, or chromosomal abnormality established as a cause. ClinVar/HGMD/OMIM contain no EF gene entries.
• Pathogenic variants / allele frequencies / somatic vs germline: Not applicable.
• Epigenetics: Not specifically characterized in EF (no methylome/ChIP studies dedicated to EF fascia in the literature surveyed).
• Clonal/somatic context: The relevant "molecular genetics" of EF is in its paraneoplastic associations — clonal hematologic disorders (aplastic anemia/PNH, MDS, T-cell and other lymphomas, myeloproliferative neoplasms) co-occur in up to ~10% of patients (PMID:9283913; PMC4553982). These are clonal diseases associated with EF, not the genetic cause of EF.

Bottom line for KB: populate genetics sections as "not applicable / acquired immune-mediated disease"; do not invent HGNC gene annotations. The gene-relevant content lives in the immunology/cytokine layer (§6), not in a causal-variant layer.

5. Environmental Information

• Environmental/occupational factors: strenuous physical activity and trauma; organic solvents (trichloroethylene), historically adulterated L-tryptophan and toxic rapeseed oil (distinct toxic syndromes that mimic EF).
• Drug exposures (iatrogenic environment): statins, phenytoin, heparin, ramipril, and immune checkpoint inhibitors (the most clinically important contemporary drug trigger; PMID:40399177, PMID:32127188).
• Lifestyle factors: intense/unaccustomed exercise is the dominant lifestyle association; no robust smoking/alcohol/diet links.
• Infectious agents (triggers, not pathogens of a primary infection): Borrelia burgdorferi (debated; [NCBITaxon:139], SARS-CoV-2 ([NCBITaxon:2697049]; PMID:38292575), Mycoplasma. EF is not an infectious disease; these are putative immune triggers.

6. Mechanism / Pathophysiology

EF is a Th2-skewed, eosinophil-and-TGF-β-driven fibrosing inflammation centered on the deep fascia, progressing from an inflammatory phase to fibrosis. Current understanding (idiopathic and ICI-related forms appear to converge mechanistically):

Causal chain (proposed): 1. Trigger (mechanical/exertional injury, drug/checkpoint blockade, infection) → release of fascial antigens / danger signals. 2. Type 2 immune activation: recruitment and degranulation of eosinophils in the fascia and elevation of interleukin-5 (IL-5) (eosinophil growth/survival factor) and IL-4 (Th2). The 2023 histological-spectrum study found upregulation of Th2–M2 markers STAT6 and IL-4 alongside Th1–M1 markers STAT1 and IFN-γ, with CD206⁺ (M2) macrophages predominating at the muscle–fascia interface (Pehl, Preuße, Allenbach et al. 2023, Rheumatology, PMID:36130069). 3. Eosinophil effector molecules (major basic protein, eosinophil cationic protein) and cytokines activate fascial fibroblasts. 4. Profibrotic signaling: TGF-β1 upregulation drives fibroblast → myofibroblast activation and excess extracellular-matrix/collagen deposition; tissue inhibitors of metalloproteinases (TIMPs) are elevated, shifting the MMP/TIMP balance toward matrix accumulation (PMID:36768300: "Elevated levels of TIMPs… reported in patients with EF"; "increase in the expression of transforming growth factor-β1"). 5. Fibrosis of deep fascia and septa → fascial thickening, skin induration, and joint contractures (the clinical end-state).

Distinctive immunopathology. EF shows perifascicular pathology with MHC class I and II upregulation (dermatomyositis-like) but, importantly, NO type I interferon signature, no hypoxia-mediated process, and no perifascicular fiber atrophy — distinguishing it mechanistically from idiopathic inflammatory myopathies (PMID:36130069). The eosinophil chemoattractants themselves were not significantly upregulated in that study, suggesting eosinophils are recruited/retained by mechanisms beyond classic chemokine gradients.

ICI-related mechanism. Checkpoint blockade (loss of PD-1/CTLA-4 restraint) is thought to unleash autoreactive T cells and a Th2/eosinophil response in fascia; notably, sirolimus (mTOR inhibitor) produced remarkable efficacy in a nivolumab-triggered case, implicating mTOR/T-cell metabolic signaling (PMID:32127188).

Molecular pathways / GO suggestions: - TGF-β receptor signaling — GO:0007179 (transforming growth factor beta receptor signaling pathway), modifier INCREASED. - IL-5 / type 2 cytokine signaling — GO:0038043 (interleukin-5–mediated signaling pathway). - Eosinophil degranulation — GO:0043308. - Extracellular matrix organization / collagen fibril deposition — GO:0030198 (ECM organization), GO:0030199 (collagen fibril organization). - Fibroblast→myofibroblast activation / chronic inflammation — GO:0006954 (inflammatory response), GO:0072537 (fibroblast activation).

Cell types (CL suggestions): - Eosinophil — CL:0000771. - Fibroblast / fascial fibroblast → myofibroblast — CL:0000057 (fibroblast); myofibroblast CL:0000186. - M2 / CD206⁺ macrophage — CL:0000890 (alternatively activated macrophage). - CD4⁺ T helper (Th2) cell — CL:0000546 (Th2 cell) / CL:0000492 (CD4⁺ T cell). - Plasma cell (hypergammaglobulinemia) — CL:0000786.

Chemical entities (CHEBI): TGF-β1 (protein), IL-5 (protein); small-molecule/marker context — collagen; eosinophil cationic protein (protein). For treatment chemicals see §12.

Molecular profiling. No large transcriptomic/proteomic/metabolomic datasets specific to EF were identified (GEO/PRIDE coverage is minimal). The 2023 Rheumatology paper (PMID:36130069) is the most granular immunophenotyping to date (immunohistochemistry/transcript markers, not omics-scale). Serum TARC/CCL17 and IL-5 are the most cited candidate activity biomarkers. This is a genuine knowledge gap worth flagging in the entry (discussions: kind: KNOWLEDGE_GAP).

7. Anatomical Structures Affected

• Primary structure: deep (muscular) fascia — the defining target. [UBERON:0007825 "deep fascia" / UBERON:0011892 "fascia of muscle"; general fascia UBERON:0007798 "vasculature"? no — UBERON:0002384 "connective tissue", UBERON:0001134 "skeletal muscle tissue" at interface].
• Subcutaneous tissue / septa — UBERON:0002072 (skin of body)/ UBERON:0001013 "adipose tissue" septa; subcutis UBERON:0002072.
• Skin (dermis, overlying) — UBERON:0002067 "dermis", UBERON:0002097 "skin of body".
• Skeletal muscle (perifascial/superficial myositis at the muscle–fascia interface) — UBERON:0001134 "skeletal muscle tissue".
• Joints (secondary — contractures) — UBERON:0000982 "skeletal joint".
• Peripheral nerve at fascial entrapment sites (e.g., median nerve → carpal tunnel) — UBERON:0001021 "nerve".

Body systems: musculoskeletal/connective-tissue (primary), integumentary (skin), immune/hematologic (eosinophilia, paraneoplastic marrow disease). Internal viscera (heart, lung, GI, kidney) are characteristically spared.

Lateralization: typically symmetric and bilateral, limb-predominant (forearms, lower legs > thighs, upper arms, trunk); hands, feet, and face usually spared — a key clinical discriminator.

Subcellular: extracellular (ECM/collagen deposition in fascia); no specific organelle pathology. GO cellular component — GO:0062023 "collagen-containing extracellular matrix".

8. Temporal Development

• Onset: Adult-predominant (peak ~30–60 years); juvenile EF exists and may be more systemic/disabling (PMID:36768300). Onset is often acute/subacute — "In 50% of cases, the onset of the disease is sudden" (PMID:36768300) — frequently following an exertional or other trigger.
• Phases: (1) early inflammatory/edematous phase (painful swelling, erythema, eosinophilia) → (2) indurative/fibrotic phase (woody induration, peau d'orange, groove sign) → (3) fibrotic/contracture end-stage.
• Course: can be self-limited in a minority, but is frequently chronic and relapsing; a substantial fraction become corticosteroid-refractory and develop persistent contractures.
• Critical window: early treatment matters — combination corticosteroid + methotrexate started early "significantly improves" outcomes and reduces residual fibrosis/contractures (multiple series; PMC12309119 early-EF case report; PMID:36768300). Delay → irreversible fibrosis.
• Remission: treatment-induced remission is achievable in most steroid-responsive patients; spontaneous remission occurs but is less common.

9. Inheritance and Population

• Epidemiology: Rare. No precise incidence/prevalence figures exist; ~>300 cases described historically and fewer than ~3,000 reported worldwide. Largest single cohort is a Mayo Clinic series of 52 patients. No reliable per-100,000 incidence is published — record as "unknown/rare" in the KB rather than fabricating a rate.
• Inheritance: Not heritable — sporadic/acquired. No AD/AR/X-linked pattern, penetrance, expressivity, anticipation, founder effect, consanguinity, or carrier-frequency data apply.
• Sex ratio: Most series show a slight male predominance or roughly equal distribution (varies by series; ICI-related EF showed M:F ≈ 1.3 with median age 57, PMID:40399177).
• Ethnicity/geography: No strong ethnic or geographic predilection established; reported worldwide.
• Key disease associations (not inheritance, but population-level comorbidity):
• Hematologic disorders in up to ~10% — aplastic anemia / AA-PNH, amegakaryocytic thrombocytopenia, MDS, T-cell and other lymphomas, CLL, myeloproliferative neoplasms, multiple myeloma (PMID:9283913 "frequently associated with hematologic disorders, especially aplastic anemia"; PMC4553982, 4-case AA series). EF with aplastic anemia carries a poorer prognosis.
• Morphea overlap in ~29–40% (PMID:36768300).
• Solid tumors (paraneoplastic, less common) and ICI-treated melanoma (PMID:40399177: melanoma was the commonest underlying tumor, 50%).

10. Diagnostics

EF is a clinicopathologic diagnosis; there is no single confirmatory blood test.

Laboratory: - CBC with differential — peripheral eosinophilia (LOINC for eosinophils/100 leukocytes e.g. LOINC:713-8). [HP:0001880]. - Serum immunoglobulins — polyclonal hypergammaglobulinemia. - ESR / CRP — elevated. - Aldolase (often elevated with normal/near-normal CK) — sensitive fascial-inflammation marker and treatment-response monitor. - ANA/anti-Scl-70/anticentromere — typically negative/absent (helps exclude systemic sclerosis). - Candidate biomarkers: TARC/CCL17, IL-5 (research).

Imaging: - MRI is the key noninvasive test: shows fascial thickening, T2 hyperintensity (edema), and post-contrast fascial enhancement; recommended where biopsy is not feasible and to guide the biopsy site (PMID:35651918 "MRI Findings of Eosinophilic Fasciitis"; PMID:36768300). [RadLex/imaging]. - Ultrasound and PET have supporting roles.

Histopathology — gold standard: - Full-thickness incisional biopsy en bloc to and including the deep muscular fascia (skin → subcutis → fascia → superficial muscle). Findings: fascial thickening, lymphoplasmacytic infiltrate ± eosinophils, fibrosis, and inflammation at the fascia–muscle interface. Tissue eosinophilia is supportive but NOT required for diagnosis (peripheral and tissue eosinophilia are often transient) (PMID:36768300; PMID:39895266 case lacking classic histology). [SNOMED CT histopathology].

Diagnostic criteria. Two proposed criteria sets: - Pinal-Fernandez et al. (2014) criteria — major: symmetric/diffuse swelling-induration-thickening of limb/trunk skin; minor: fascial thickening with inflammation/eosinophil infiltrate on biopsy. Exclusion of systemic sclerosis required. - Jinnin et al. (2018, Japanese) criteria — require symmetrical plate-like sclerotic lesions of extremities plus fascial thickening/inflammation, with SSc excluded (PMID:36768300).

Differential diagnosis (key to exclude): systemic sclerosis/scleroderma (spares fingers, no Raynaud/nailfold change, no visceral disease in EF), morphea (can overlap), nephrogenic systemic fibrosis, scleromyxedema, eosinophilia–myalgia syndrome, toxic-oil syndrome, hypereosinophilic syndrome, graft-versus-host disease, and chronic Lyme-associated fibrosis.

Genetic testing: Not indicated (no causal gene). Genetic/marrow work-up (e.g., bone marrow biopsy, cytogenetics, flow for PNH clone) is reserved for screening the associated hematologic disorders, not for diagnosing EF itself.

Screening: No population screening. Given the ~10% hematologic association, CBC surveillance for cytopenias during follow-up is prudent.

11. Outcome / Prognosis

• Overall: EF is not directly life-threatening; prognosis is generally favorable for the fascial/skin disease when treated early, but morbidity from joint contractures and residual fibrosis is significant.
• Predictors of poor outcome / refractory disease: truncal involvement, juvenile onset, presence of morphea-like lesions, dermal sclerosis, delayed treatment, and absence of peripheral eosinophilia have all been associated with worse response and contracture risk. Early combination immunosuppression predicts better recovery.
• Mortality: Disease-specific mortality is low; excess mortality is driven by the associated hematologic malignancies / aplastic anemia, which carry a poor prognosis (PMID:9283913; PMC4553982).
• Complications: flexion contractures, carpal tunnel syndrome, persistent limb stiffness/disability, secondary functional impairment; rarely, evolution of an associated hematologic neoplasm.
• Recovery: many achieve substantial or complete remission on steroids ± methotrexate; a refractory subset needs escalation (§12). Spontaneous remission occurs in a minority.

12. Treatment

Suggested MAXO/NCIT/CHEBI annotations in brackets. No therapy is FDA-approved specifically for EF; management is from case series/expert consensus.

First-line — systemic glucocorticoids: - Prednisone (or equivalent) ~0.5–1 mg/kg/day, tapered over months; pulse IV methylprednisolone for severe disease. Response in the inflammatory phase is often good (PMID:36768300). [MAXO:0000058? use MAXO:0000302 pharmacotherapy or NCIT:C15986 Pharmacotherapy; therapeutic_agent: prednisone CHEBI:8378, methylprednisolone CHEBI:6888; therapeutic_modality SMALL_MOLECULE; treatment class NCIT:C2322 Corticosteroid].

Steroid-sparing / second-line (relapse or refractory): - Methotrexate (15–25 mg/week) — most recommended steroid-sparing agent; early steroid+MTX combination improves outcomes (PMID:36768300). [NCIT:C15986 Pharmacotherapy; methotrexate CHEBI:44185]. - Mycophenolate mofetil — commonly used alternative. [CHEBI:8764]. - Cyclosporine A — successful in some refractory cases (PMID:36768300). [CHEBI:4031]. - Azathioprine, hydroxychloroquine, cyclophosphamide — additional options.

Biologic / targeted (refractory disease): - Rituximab (anti-CD20) — reported benefit in refractory EF (clinical-experience review, PMC8021286). [rituximab NCIT:C1702; MONOCLONAL_ANTIBODY]. - Tocilizumab (anti–IL-6R) — case reports of benefit. - Anti–IL-5 agents — reslizumab / mepolizumab — mechanistically rational (IL-5/eosinophil axis); reslizumab achieved symptom resolution in refractory EF (PMID:32913886). [reslizumab/mepolizumab; MONOCLONAL_ANTIBODY]. - TNF inhibitors (infliximab) — variable reports. - JAK inhibitors — emerging interest. - Sirolimus (mTOR inhibitor) — "remarkable efficacy" in nivolumab-induced EF (PMID:32127188). [sirolimus CHEBI:9168]. - IVIG — adjunct in refractory/contracture-prone disease.

Phototherapy: UVA1 / PUVA phototherapy for cutaneous sclerosis. [MAXO/phototherapy].

Supportive / rehabilitative: - Physical therapy / occupational therapy — essential to prevent and treat contractures and preserve range of motion. [MAXO:0000011 physical therapy; NCIT:C15315 Rehabilitation]. - Surgical release of established contractures (e.g., fasciectomy, carpal tunnel release) in selected cases. [MAXO:0000004 surgical procedure].

ICI-related EF: withhold/hold the checkpoint inhibitor, treat with corticosteroids ± steroid-sparing agents; consider sirolimus or anti–IL-5 in refractory cases (PMID:40399177).

Treatment strategy: Early high-dose steroid + methotrexate is the prevailing initial regimen; escalate to biologics (rituximab, anti–IL-5, tocilizumab) for refractory disease; integrate PT/OT throughout. No randomized trials exist — evidence is observational. Pharmacogenomics: standard considerations apply to methotrexate (folate pathway) and azathioprine (TPMT/NUDT15 genotyping before thiopurines) — general, not EF-specific.

13. Prevention

• Primary prevention: None established for idiopathic EF. For iatrogenic (ICI-related) EF, vigilance and early recognition during checkpoint-inhibitor therapy; review of causative drugs (statins, phenytoin, heparin) when EF arises after exposure.
• Secondary prevention (early detection): prompt biopsy/MRI and early immunosuppression to prevent the inflammatory→fibrotic→contracture transition is the most effective "preventive" lever (prevents irreversible disability).
• Tertiary prevention: aggressive PT/OT and contracture management; surveillance CBCs to catch associated hematologic disease early (~10% risk).
• Immunization / public-health / counseling: Not applicable (non-genetic, non-infectious primary disease — no vaccine, no carrier/genetic counseling indicated).

14. Other Species / Natural Disease

• Taxonomy: EF is described essentially only in humans ([NCBITaxon:9606 Homo sapiens]).
• Naturally occurring animal disease: No well-established spontaneous EF analogue is catalogued in OMIA. Eosinophilic and fibrosing fasciitis-like conditions occur in veterinary medicine (e.g., eosinophilic dermatitis/panniculitis in dogs/cats), but a direct Shulman-syndrome homologue is not recognized.
• Comparative biology / orthologs: Because EF has no causal gene, there are no disease-defining orthologs; the relevant pathways (IL-5, TGF-β1, eosinophil biology) are highly conserved across mammals.
• Zoonotic potential / cross-species transmission: Not applicable.

15. Model Organisms

• Dedicated animal model: None validated. There is no established knockout/transgenic/induced rodent model that faithfully recapitulates Shulman-syndrome EF. This is a real knowledge gap (flag as discussions: kind: KNOWLEDGE_GAP in the entry).
• Surrogate/adjacent systems: Eosinophil/IL-5 biology and TGF-β–driven dermal/fascial fibrosis are studied in mouse models of scleroderma/fibrosis (e.g., bleomycin-induced skin fibrosis) and IL-5 transgenic / eosinophilia models, which inform mechanism but do not reproduce the EF phenotype specifically. Any such evidence cited should be tagged evidence_source: MODEL_ORGANISM and must not be the sole support for human phenotype claims (per dismech policy), and ideally flagged HUMAN_MODEL_MISMATCH given the absence of a true model.
• In vitro: patient fascial fibroblast cultures and eosinophil–fibroblast co-culture systems are the main experimental substrate for the IL-5/TGF-β/TIMP findings — tag IN_VITRO.

Consolidated Citation List (verify each with just fetch-reference before use)

Sources (web): - Mazilu et al. 2023, MDPI / IJMS · PMC mirror - Pehl/Preuße 2023, Rheumatology (PubMed) - ICI-related EF 2025 (PubMed) - Aplastic anemia in EF (PubMed) · Severe AA + EF, 4 cases (PMC) - Reslizumab in refractory EF (PubMed) · Sirolimus in nivolumab-EF (PubMed) - MRI findings (PubMed) · EF following COVID-19 (PubMed) - Biologic treatment in resistant EF (PMC) · Early EF diagnosis/treatment (PMC) - Medscape EF overview

Quick orientation for the KB entry

• MONDO:0009175 confirmed; ICD-10 M35.4, ICD-11 4A43.0; no OMIM (acquired, non-Mendelian).
• Model the pathophysiology as a causal chain: trigger → Th2/eosinophil activation (IL-5↑, IL-4/STAT6) → fibroblast activation via TGF-β1↑ + TIMP↑/ECM deposition → fascial fibrosis → contractures. Consider declaring conforms_to: fibrotic_response#Mesenchymal Cell Activation (tissue injury → inflammation → fibroblast activation → ECM → organ/limb dysfunction maps cleanly here).
• Leave genetics/inheritance/model-organism sections explicitly "not applicable / knowledge gap" rather than fabricating gene or variant annotations.
• Capture the hematologic-disorder association (~10%) and morphea overlap (29–40%) — good candidates for comorbidity/association_signals and differentiating notes.

One caution from your own memory bank that applies here: NCIT drug terms often fail therapeutic_agent validation, so prefer CHEBI for prednisone/methotrexate/MMF/cyclosporine/sirolimus, and reserve NCIT for biologics (rituximab) that lack a clean CHEBI term.