Keratosis pilaris atrophicans (KPA) is an umbrella term for a group of rare, genetically heterogeneous genodermatoses of follicular keratinization in which follicular hyperkeratosis with perifollicular inflammation progresses to atrophy and scarring, most often affecting the face, eyebrows, and scalp. The three principal clinical variants are keratosis pilaris atrophicans faciei (ulerythema ophryogenes), atrophoderma vermiculatum, and keratosis follicularis spinulosa decalvans (KFSD, MBTPS2-related X-linked disease). Most KPA is sporadic, but a documented autosomal recessive LRP1 loss-of-function cause exists, and the keratosis pilaris atrophicans faciei/ulerythema ophryogenes phenotype specifically is a recognized, frequent dermatologic feature of monosomy 18p and of the RAS-MAPK-driven RASopathies (chiefly cardiofaciocutaneous syndrome, also Noonan syndrome), reflecting genetic heterogeneity converging on a shared follicular pathophysiology rather than a single Mendelian cause.
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name: Keratosis Pilaris Atrophicans
creation_date: "2026-08-26T00:00:00Z"
category: Mendelian
disease_term:
preferred_term: keratosis pilaris atrophicans
term:
id: MONDO:0018855
label: keratosis pilaris atrophicans
description: >-
Keratosis pilaris atrophicans (KPA) is an umbrella term for a group of rare,
genetically heterogeneous genodermatoses of follicular keratinization in
which follicular hyperkeratosis with perifollicular inflammation progresses
to atrophy and scarring, most often affecting the face, eyebrows, and scalp.
The three principal clinical variants are keratosis pilaris atrophicans
faciei (ulerythema ophryogenes), atrophoderma vermiculatum, and keratosis
follicularis spinulosa decalvans (KFSD, MBTPS2-related X-linked disease).
Most KPA is sporadic, but a documented autosomal recessive LRP1
loss-of-function cause exists, and the keratosis pilaris atrophicans
faciei/ulerythema ophryogenes phenotype specifically is a recognized,
frequent dermatologic feature of monosomy 18p and of the RAS-MAPK-driven
RASopathies
(chiefly cardiofaciocutaneous syndrome, also Noonan syndrome), reflecting
genetic heterogeneity converging on a shared follicular pathophysiology
rather than a single Mendelian cause.
parents:
- Genodermatosis
has_subtypes:
- name: Keratosis Pilaris Atrophicans Faciei
display_name: Keratosis Pilaris Atrophicans Faciei (Ulerythema Ophryogenes)
subtype_term:
preferred_term: keratosis pilaris atrophicans faciei
term:
id: MONDO:0859588
label: keratosis pilaris atrophicans faciei
mappings:
mondo_mappings:
- term:
id: MONDO:0018086
label: ulerythema ophryogenesis
mapping_predicate: skos:closeMatch
mapping_source: MONDO
mapping_justification: >-
MONDO models "ulerythema ophryogenesis" (MONDO:0018086) and "keratosis
pilaris atrophicans faciei" (MONDO:0859588) as two separate is-a
children of keratosis pilaris atrophicans, but the clinical and
dermatology literature treats "ulerythema ophryogenes" as the
classic/eponymous name for the same faciei variant (e.g. PMID:24801913
writes "ulerythema ophryogenes (keratosis pilaris atrophicans
faciei)"). closeMatch records this near-synonymy without asserting
formal ontological identity.
description: >-
Ulerythema ophryogenes (UO) begins with erythematous, keratotic follicular
papules of the lateral eyebrows and cheeks that progress to perifollicular
scarring, sparse or absent lateral eyebrows, and (rarely) extension to the
forehead or scalp; eyelashes are typically spared. Most cases are
sporadic, but autosomal dominant familial transmission has been reported.
The same phenotype is a recognized, frequent cutaneous marker of monosomy
18p (five reported cases as of 2014) and of RAS-MAPK pathway
dysregulation in the RASopathies, occurring in up to 90% of
molecularly-confirmed cardiofaciocutaneous syndrome (see
kb/groupings/RASopathies.yaml).
evidence:
- reference: PMID:24801913
reference_title: "Trias of keratosis pilaris, ulerythema ophryogenes and 18p monosomy: Zouboulis syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris and ulerythema ophryogenes (keratosis pilaris
atrophicans faciei) are part of a group of hereditary disorders of hair
follicle keratinization involving follicular inflammation and
subsequent atrophy.
explanation: Confirms ulerythema ophryogenes and keratosis pilaris atrophicans faciei denote the same clinical entity within the KPA spectrum.
- reference: PMID:40761190
reference_title: "Successful treatment of ulerythema ophryogenes with pulsed dye laser: a case report."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
presented a progressive erythema and confluent horny follicular
erythematous papules with areas of alopecia around the lateral third of
eyebrows without signs of pitted or atrophic scars, which has been
evident since childhood
explanation: Describes the characteristic clinical presentation of ulerythema ophryogenes, including lateral eyebrow follicular papules and alopecia.
- name: Atrophoderma Vermiculatum
subtype_term:
preferred_term: atrophoderma vermiculata
term:
id: MONDO:0008849
label: atrophoderma vermiculata
description: >-
Atrophoderma vermiculatum (also folliculitis ulerythematosa reticulata)
presents in childhood as symmetric follicular papules of the cheeks and
preauricular skin that slowly evolve into a reticulated, pitted
"honeycombed"/"worm-eaten" atrophic scarring pattern, with a slowly
progressive course.
evidence:
- reference: PMID:11260551
reference_title: "Laser treatment of atrophoderma vermiculata."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Atrophoderma vermiculata is a rare genodermatosis with usual onset in
childhood, characterized by a "honey-combed" reticular atrophy of the
cheeks. The course is generally slow, with progressive worsening.
explanation: Describes the defining clinical morphology and slowly progressive course of atrophoderma vermiculatum.
- reference: PMID:9720693
reference_title: "Folliculitis ulerythematosa reticulata (atrophoderma vermiculata): early detection of a case with unilateral lesions."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Unilateral folliculitis ulerythematosa reticulata (a variant of
keratosis pilaris atrophicans) is strikingly rare, and its very early
clinical and microscopic changes are demonstrated in this case report.
explanation: Confirms atrophoderma vermiculatum/folliculitis ulerythematosa reticulata is classified as a variant within the keratosis pilaris atrophicans spectrum.
- name: Keratosis Follicularis Spinulosa Decalvans
subtype_term:
preferred_term: keratosis follicularis spinulosa decalvans
term:
id: MONDO:0000136
label: keratosis follicularis spinulosa decalvans
description: >-
KFSD is the most extensive KPA variant, with generalized follicular
hyperkeratosis and progressive cicatricial alopecia of the scalp,
eyebrows, and eyelashes, most often caused by X-linked recessive MBTPS2
(site-2 protease) variants; rarer autosomal forms (e.g. CST6) are also
reported. Photophobia, corneal dystrophy, and other ocular findings can
coexist. This subtype's full pathophysiology, phenotypes, genetics, and
treatment are curated in its own dedicated dismech entry,
kb/disorders/Keratosis_Follicularis_Spinulosa_Decalvans.yaml; it is
cross-referenced here rather than duplicated.
genes:
- preferred_term: MBTPS2
term:
id: hgnc:15455
label: MBTPS2
inheritance:
- name: X-linked recessive
inheritance_term:
preferred_term: X-linked recessive inheritance
term:
id: HP:0001419
label: X-linked recessive inheritance
evidence:
- reference: ORPHA:2340
reference_title: "Keratosis follicularis spinulosa decalvans"
supports: SUPPORT
evidence_source: OTHER
snippet: "- Autosomal dominant\n- Autosomal recessive\n- X-linked recessive"
explanation: >-
Orphanet records three inheritance modes for KFSD — autosomal dominant,
autosomal recessive, and X-linked recessive — without ranking them. The
X-linked recessive form is the one attributable to MBTPS2 and is the
best characterized, which is why it is curated here; the quote is given
in full so the other two modes are not silently dropped.
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris atrophicans (KPA) is a group of rare genodermatoses
characterised by perifollicular keratosis and inflammation that
progresses to atrophy and scars of the facial skin.
explanation: Frames KFSD as one of the genodermatoses within the broader KPA group whose shared endpoint is perifollicular keratosis/inflammation progressing to atrophy and scarring.
genetic:
- name: LRP1 Autosomal Recessive Variants
gene_term:
preferred_term: LRP1
term:
id: hgnc:6692
label: LRP1
association: >-
A homozygous missense variant (p.Lys1245Arg) in LRP1 was identified as
the cause of autosomal recessive, mixed-type keratosis pilaris atrophicans
in a large consanguineous Pakistani pedigree, the first reported causal
gene for the root KPA entity itself (as distinct from the MBTPS2-caused
KFSD subtype).
relationship_type: CAUSATIVE
variant_origin: GERMLINE
inheritance:
- name: Autosomal recessive
inheritance_term:
preferred_term: Autosomal recessive inheritance
term:
id: HP:0000007
label: Autosomal recessive inheritance
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
A large consanguineous Pakistani pedigree segregating autosomal
recessive KPA of a mixed type was subject to autozygosity mapping and
whole exome sequencing.
explanation: Establishes autosomal recessive inheritance of the LRP1-associated KPA family.
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Genetic analyses identified a unique homozygous missense variant
(K1245R) in the LRP1 in all affected family members.
explanation: Identifies the specific causal LRP1 variant segregating with disease in the affected family.
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
The LRP1 mRNA and LRP1 protein levels in fibroblasts of affected
individuals were markedly reduced when compared with controls.
Similarly, the LRP1-mediated cellular uptake of alpha(2)M was reduced in
patient fibroblasts.
explanation: Functional fibroblast assays confirm the LRP1 variant causes loss of LRP1 expression and receptor-mediated endocytic function.
- name: 18p Deletion (Monosomy 18p)
association: Chromosomal Alteration
subtype: Keratosis Pilaris Atrophicans Faciei
relationship_type: RISK_FACTOR
variant_origin: GERMLINE
notes: >-
Ulerythema ophryogenes/keratosis pilaris atrophicans faciei with
concurrent keratosis pilaris of the trunk and limbs has been reported in
at least five patients with monosomy of the short arm of chromosome 18
since the association was first described in 1994, prompting proposal of
a distinct "Zouboulis syndrome" trias. No single causal gene within the
18p deletion region has been confirmed; a candidate role for LAMA1 was
proposed but not substantiated with further evidence.
evidence:
- reference: PMID:8041661
reference_title: "Ulerythema ophryogenes and keratosis pilaris in a child with monosomy 18p."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We report a 13-year-old boy with deletion of the short arm of
chromosome 18 and follicular, partially inflammatory, keratotic papules
of the eyebrows, foreskin, and cheeks (ulerythema ophryogenes) as well
as the shoulders, upper back, upper arms, and thighs (keratosis
pilaris), initially diagnosed as atopic dermatitis.
explanation: First reported case establishing the association between monosomy 18p and ulerythema ophryogenes/keratosis pilaris.
- reference: PMID:24801913
reference_title: "Trias of keratosis pilaris, ulerythema ophryogenes and 18p monosomy: Zouboulis syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We have reviewed the five almost identical cases that have been
reported in 20 years and we suggest the existence of a new rare
syndrome characterized by the trias keratosis pilaris, ulerythema
ophryogenes and monosomy 18p.
explanation: Reviews five reported cases confirming the recurrent association of monosomy 18p with keratosis pilaris and ulerythema ophryogenes.
- name: RASopathy RAS-MAPK Pathway Variants (Cardiofaciocutaneous and Noonan Syndrome)
association: >-
Germline gain-of-function variants in RAS-MAPK pathway genes (BRAF,
MAP2K1, MAP2K2, KRAS in cardiofaciocutaneous syndrome; PTPN11 and others
in Noonan syndrome) cause the RASopathies, in which ulerythema
ophryogenes/keratosis pilaris atrophicans faciei is a frequent
dermatologic manifestation rather than an isolated causal relationship to
KPA itself; see kb/groupings/RASopathies.yaml for the cross-disease
grouping.
subtype: Keratosis Pilaris Atrophicans Faciei
relationship_type: RISK_FACTOR
variant_origin: GERMLINE
evidence:
- reference: PMID:21062266
reference_title: "Dermatological findings in 61 mutation-positive individuals with cardiofaciocutaneous syndrome."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: "Ulerythema ophryogenes was common, occurring in 90% (55/61)."
explanation: Quantifies ulerythema ophryogenes as a highly frequent dermatologic finding in a mutation-positive cardiofaciocutaneous syndrome cohort.
- reference: PMID:30141192
reference_title: "Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar
hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50
naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively.
explanation: An independent prospective cohort confirms ulerythema ophryogenes as a frequent (44%) dermatologic feature of cardiofaciocutaneous syndrome.
- reference: PMID:36541891
reference_title: "Dermatological manifestations, management, and care in RASopathies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
They can affect dermis and epidermis, causing pigmented lesions
(melanocytic nevi, café-au-lait spots, and lentigines), hyperkeratosis
(keratosis pilaris, ulerythema ophryogenes, and palmoplantar keratosis)
or hyperplasia.
explanation: Review confirms ulerythema ophryogenes/keratosis pilaris as a recognized dermatologic hallmark across the RASopathies.
pathophysiology:
- name: Follicular Keratinocyte Hyperproliferation and Plugging
description: >-
Across the genetically heterogeneous KPA spectrum, the proximal shared
lesion is abnormal follicular keratinocyte differentiation, causing
hyperkeratotic plugging of the follicular infundibulum and the clinical
finding of hyperkeratotic follicular papules.
cell_types:
- preferred_term: keratinocyte
term:
id: CL:0000312
label: keratinocyte
- preferred_term: hair follicle cell
term:
id: CL:0002559
label: hair follicle cell
biological_processes:
- preferred_term: keratinization
term:
id: GO:0031424
label: keratinization
modifier: ABNORMAL
- preferred_term: keratinocyte differentiation
term:
id: GO:0030216
label: keratinocyte differentiation
modifier: ABNORMAL
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris atrophicans (KPA) is a group of rare genodermatoses
characterised by perifollicular keratosis and inflammation that
progresses to atrophy and scars of the facial skin.
explanation: Establishes the shared proximal lesion (perifollicular keratosis) common to the KPA spectrum.
downstream:
- target: Perifollicular Inflammation
description: >-
Follicular keratin plugging incites a perifollicular inflammatory
response.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- target: Follicular hyperkeratosis
causal_link_type: DIRECT
- target: Keratosis pilaris
causal_link_type: DIRECT
- name: LRP1 Loss of Function and Impaired Endocytic Receptor Signaling
description: >-
In the LRP1-associated autosomal recessive KPA family, a homozygous LRP1
missense variant markedly reduces LRP1 mRNA/protein levels and
LRP1-mediated endocytic uptake in patient fibroblasts. LRP1 is a
multifunctional endocytic and immune-regulatory receptor, and its loss is
proposed to contribute to the inflammatory component of the disease.
genes:
- preferred_term: LRP1
term:
id: hgnc:6692
label: LRP1
cell_types:
- preferred_term: fibroblast
term:
id: CL:0000057
label: fibroblast
molecular_functions:
- preferred_term: low-density lipoprotein particle receptor activity
term:
id: GO:0005041
label: low-density lipoprotein particle receptor activity
modifier: LOSS_OF_FUNCTION
biological_processes:
- preferred_term: receptor-mediated endocytosis
term:
id: GO:0006898
label: receptor-mediated endocytosis
modifier: DECREASED
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: IN_VITRO
snippet: >-
The LRP1 mRNA and LRP1 protein levels in fibroblasts of affected
individuals were markedly reduced when compared with controls.
Similarly, the LRP1-mediated cellular uptake of alpha(2)M was reduced in
patient fibroblasts.
explanation: Functional assays demonstrate loss of LRP1 expression and receptor-mediated endocytic uptake in patient cells.
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The inflammatory characteristics of the KPA entity in our family
suggest a link to the immune-regulatory functions of LRP1.
explanation: Authors propose LRP1's immune-regulatory role links its loss of function to the inflammatory phenotype.
downstream:
- target: Perifollicular Inflammation
description: Loss of LRP1 immune-regulatory function is proposed to promote perifollicular inflammation.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: RAS-MAPK Pathway Dysregulation (RASopathy Context)
description: >-
In individuals with cardiofaciocutaneous or Noonan syndrome, germline
gain-of-function RAS-MAPK pathway variants (e.g. BRAF, MAP2K1, MAP2K2,
KRAS, PTPN11) drive constitutive Ras/MAPK signaling in developing skin and
pilosebaceous units, producing ulerythema ophryogenes/keratosis pilaris
atrophicans faciei as a dermatologic manifestation of the underlying
RASopathy rather than of an independent follicular disease process (see
kb/groupings/RASopathies.yaml).
cell_types:
- preferred_term: keratinocyte
term:
id: CL:0000312
label: keratinocyte
biological_processes:
- preferred_term: Ras protein signal transduction
term:
id: GO:0007265
label: Ras protein signal transduction
modifier: GAIN_OF_FUNCTION
evidence:
- reference: PMID:36541891
reference_title: "Dermatological manifestations, management, and care in RASopathies."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
RASopathies are rare genetic disorders caused by germline pathogenic
variants in genes belonging to the RAS/MAPK pathway, which signals cell
proliferation, differentiation, survival and death.
explanation: Confirms germline RAS/MAPK pathway dysregulation as the shared mechanism underlying the RASopathies, of which ulerythema ophryogenes is a dermatologic feature.
downstream:
- target: Follicular Keratinocyte Hyperproliferation and Plugging
description: >-
RAS-MAPK pathway dysregulation in the RASopathies produces follicular
hyperkeratosis and inflammation phenotypically convergent with the
other causes of keratosis pilaris atrophicans faciei.
causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
- name: Perifollicular Inflammation
description: >-
Follicular keratin occlusion (and, in the LRP1-deficient family, impaired
immune regulation) triggers a perifollicular inflammatory infiltrate,
producing the characteristic erythema surrounding follicular papules.
cell_types:
- preferred_term: hair follicle cell
term:
id: CL:0002559
label: hair follicle cell
biological_processes:
- preferred_term: inflammatory response
term:
id: GO:0006954
label: inflammatory response
modifier: INCREASED
evidence:
- reference: PMID:8041661
reference_title: "Ulerythema ophryogenes and keratosis pilaris in a child with monosomy 18p."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
follicular, partially inflammatory, keratotic papules of the eyebrows,
foreskin, and cheeks (ulerythema ophryogenes)
explanation: Clinical description confirms the inflammatory component of the follicular papules characteristic of the disease.
downstream:
- target: Follicular Atrophy and Cicatricial Change
description: Chronic perifollicular inflammation leads to follicular destruction and secondary atrophic/cicatricial change.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- target: Perifollicular erythema
causal_link_type: DIRECT
- name: Follicular Atrophy and Cicatricial Change
description: >-
Repeated cycles of follicular inflammation lead to loss of the follicular
unit and dermal extracellular matrix remodeling, producing the
characteristic atrophic, scar-like depressions and (in the faciei and
KFSD variants) hair loss.
cell_types:
- preferred_term: hair follicle cell
term:
id: CL:0002559
label: hair follicle cell
biological_processes:
- preferred_term: extracellular matrix organization
term:
id: GO:0030198
label: extracellular matrix organization
modifier: ABNORMAL
evidence:
- reference: PMID:11260551
reference_title: "Laser treatment of atrophoderma vermiculata."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
characterized by a "honey-combed" reticular atrophy of the cheeks. The
course is generally slow, with progressive worsening.
explanation: Describes the progressive atrophic scarring endpoint of the follicular disease process.
downstream:
- target: Atrophic scars
causal_link_type: DIRECT
- target: Sparse lateral eyebrow
description: Follicular destruction in the lateral eyebrow region produces localized hair loss in ulerythema ophryogenes.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
- target: Scarring alopecia of scalp
description: >-
Follicular destruction extending to scalp hair follicles produces
permanent cicatricial alopecia, most pronounced in the extensive KFSD
end of the spectrum but also documented on the scalp in general KPA
case series.
causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
histopathology:
- name: Follicular Keratotic Plugging
description: >-
The infundibulum of the affected hair follicle is markedly dilated and
filled with a compact keratotic plug, the tissue-level correlate of the
"Follicular Keratinocyte Hyperproliferation and Plugging" pathophysiology
node.
diagnostic: true
finding_term:
preferred_term: Hyperkeratosis
term:
id: NCIT:C35541
label: Hyperkeratosis
evidence:
- reference: PMID:12602976
reference_title: "Atrophodermia vermiculata: case report and review of the literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The hair follicle was widely dilated and was filled with a keratotic
plug.
explanation: Direct histopathologic description of the dilated, keratin-plugged follicle characteristic of the KPA spectrum.
- name: Perifollicular and Perivascular Lymphocytic Inflammation
description: >-
Mild inflammatory infiltrate surrounds the plugged follicle in a
perifollicular and perivascular distribution, the tissue-level correlate
of the "Perifollicular Inflammation" pathophysiology node.
diagnostic: true
finding_term:
preferred_term: Chronic Inflammatory Infiltrate
term:
id: NCIT:C35980
label: Chronic Inflammatory Infiltrate
evidence:
- reference: PMID:12602976
reference_title: "Atrophodermia vermiculata: case report and review of the literature."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The connective tissue showed mild inflammation in perifollicular and
perivascular distribution.
explanation: Direct histopathologic description of the perifollicular/perivascular inflammatory infiltrate surrounding the affected follicle.
- name: Follicular Destruction and Dermal Fibrosis
description: >-
Sustained follicular inflammation leads to destruction of the follicular
unit and dermal fibrosis/elastotic change, the tissue-level correlate of
the "Follicular Atrophy and Cicatricial Change" pathophysiology node and
the histologic basis for the clinically observed atrophic scarring.
diagnostic: true
finding_term:
preferred_term: Fibrosis
term:
id: NCIT:C3044
label: Fibrosis
evidence:
- reference: PMID:8166484
reference_title: "Clinical findings, cutaneous pathology, and response to therapy in 21 patients with keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Histopathologic examination revealed hyperkeratosis of the upper
follicle with an inflammatory response that resulted in follicular
destruction.
explanation: A 21-patient general KPA case series confirms the inflammatory follicular destruction mechanism underlying the atrophic/scarring endpoint.
- reference: PMID:9720693
reference_title: "Folliculitis ulerythematosa reticulata (atrophoderma vermiculata): early detection of a case with unilateral lesions."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Histologic investigations showed aberrant pilosebaceous units and
elastotic material in the papillary dermis.
explanation: Documents the dermal elastotic/fibrotic change accompanying early follicular destruction in atrophoderma vermiculatum.
phenotypes:
- category: Dermatologic
name: Follicular hyperkeratosis
description: >-
Hyperkeratotic, horny follicular papules are the defining primary lesion
across all KPA variants.
phenotype_term:
preferred_term: Follicular hyperkeratosis
term:
id: HP:0007502
label: Follicular hyperkeratosis
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris atrophicans (KPA) is a group of rare genodermatoses
characterised by perifollicular keratosis and inflammation that
progresses to atrophy and scars of the facial skin.
explanation: Confirms perifollicular hyperkeratosis as the defining primary feature of the KPA spectrum.
- category: Dermatologic
name: Keratosis pilaris of extensor limbs
description: >-
Keratosis pilaris of the extensor aspects of the limbs is a common
associated finding alongside the facial/scalp KPA variants.
phenotype_term:
preferred_term: Keratosis pilaris
term:
id: HP:0032152
label: Keratosis pilaris
evidence:
- reference: PMID:26142438
reference_title: "Whole exome sequencing identifies LRP1 as a pathogenic gene in autosomal recessive keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris of extensor areas of limbs is a common associated
finding.
explanation: Establishes keratosis pilaris of the limbs as a common associated finding in KPA.
- category: Dermatologic
name: Perifollicular erythema
phenotype_term:
preferred_term: Perifollicular erythema
term:
id: HP:0031286
label: Perifollicular erythema
temporality: CHRONIC
evidence:
- reference: PMID:8041661
reference_title: "Ulerythema ophryogenes and keratosis pilaris in a child with monosomy 18p."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
follicular, partially inflammatory, keratotic papules of the eyebrows,
foreskin, and cheeks (ulerythema ophryogenes)
explanation: Describes the inflammatory, erythematous character of the follicular papules.
- category: Dermatologic
name: Sparse lateral eyebrow
subtype: Keratosis Pilaris Atrophicans Faciei
description: >-
Progressive follicular scarring of the lateral eyebrows produces
localized eyebrow hair loss, a hallmark of ulerythema ophryogenes.
phenotype_term:
preferred_term: Sparse lateral eyebrow
term:
id: HP:0005338
label: Sparse lateral eyebrow
evidence:
- reference: PMID:40761190
reference_title: "Successful treatment of ulerythema ophryogenes with pulsed dye laser: a case report."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
presented a progressive erythema and confluent horny follicular
erythematous papules with areas of alopecia around the lateral third of
eyebrows without signs of pitted or atrophic scars
explanation: Case report documents lateral eyebrow alopecia as a characteristic clinical finding of ulerythema ophryogenes.
- category: Dermatologic
name: Atrophic facial scarring
description: >-
Chronic follicular inflammation resolves into atrophic, scar-like
follicular depressions; in atrophoderma vermiculatum these coalesce into
a distinctive reticulated ("honeycombed") pattern on the cheeks.
phenotype_term:
preferred_term: Reticulated ("honeycombed") atrophic facial scarring
term:
id: HP:0001075
label: Atrophic scars
clinical_course: PROGRESSIVE
evidence:
- reference: PMID:11260551
reference_title: "Laser treatment of atrophoderma vermiculata."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
characterized by a "honey-combed" reticular atrophy of the cheeks. The
course is generally slow, with progressive worsening.
explanation: Establishes the progressive, reticulated atrophic scarring pattern characteristic of atrophoderma vermiculatum.
- category: Dermatologic
name: Scarring alopecia of scalp
description: >-
Chronic follicular inflammation and destruction can extend to the scalp,
producing permanent cicatricial hair loss. This is the defining, most
extensive endpoint of the KPA spectrum (most pronounced in the KFSD
subtype) but is also documented on the scalp in general/mixed-type KPA
case series, not only in KFSD.
phenotype_term:
preferred_term: Scarring alopecia of scalp
term:
id: HP:0004552
label: Scarring alopecia of scalp
clinical_course: PROGRESSIVE
evidence:
- reference: PMID:8166484
reference_title: "Clinical findings, cutaneous pathology, and response to therapy in 21 patients with keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Keratosis pilaris atrophicans defines a group of cutaneous disorders
characterized by follicular hyperkeratosis and scarring.
explanation: General definitional statement establishing scarring as a defining feature across the KPA spectrum, not only the KFSD subtype.
- reference: PMID:8166484
reference_title: "Clinical findings, cutaneous pathology, and response to therapy in 21 patients with keratosis pilaris atrophicans."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The cutaneous lesions consisted of follicular papules with scalp
involvement present in eight individuals.
explanation: Quantifies scalp involvement (8/21, ~38%) in a general KPA cohort not restricted to the KFSD subtype, supporting a root-level (not KFSD-only) phenotype.
treatments:
- name: Topical Retinoid Therapy
description: >-
Topical retinoids (e.g. tretinoin) are used to reduce follicular
hyperkeratosis and papule formation, analogous to their use in other
keratinization disorders; response in KPA is often incomplete.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: tretinoin
term:
id: CHEBI:15367
label: all-trans-retinoic acid
target_mechanisms:
- target: Follicular Keratinocyte Hyperproliferation and Plugging
treatment_effect: MODULATES
description: >-
Topical retinoids normalize follicular keratinocyte differentiation and
reduce keratin plugging of the infundibulum, the shared proximal lesion
across the KPA spectrum.
notes: >-
No controlled trial evidence for topical retinoids in KPA specifically was
identified; this reflects extrapolation from general keratinization
disorder management. treatment_effect is recorded as MODULATES rather
than INHIBITS because retinoid action on keratinocyte differentiation is
not a simple unidirectional block of the mechanism.
- name: Topical Corticosteroid Therapy
description: >-
Topical corticosteroids are used to reduce perifollicular inflammation
and erythema.
therapeutic_modality: SMALL_MOLECULE
treatment_term:
preferred_term: Topical Corticosteroid Therapy
term:
id: NCIT:C122078
label: Topical Corticosteroid Therapy
target_mechanisms:
- target: Perifollicular Inflammation
treatment_effect: INHIBITS
description: >-
Topical corticosteroids suppress the perifollicular inflammatory
response, reducing the erythema surrounding follicular papules.
- name: Pulsed Dye Laser Therapy
description: >-
Pulsed dye laser treats the erythema, follicular papules, and associated
alopecia of ulerythema ophryogenes and atrophoderma vermiculatum, with
case reports of clinically significant improvement in erythema and
partial hair regrowth after a single session.
therapeutic_modality: DEVICE
treatment_term:
preferred_term: Laser Therapy
term:
id: NCIT:C15466
label: Laser Therapy
target_mechanisms:
- target: Perifollicular Inflammation
treatment_effect: MODULATES
description: >-
Pulsed dye laser selectively targets the dilated vasculature underlying
perifollicular erythema (vascular photothermolysis), distinct from the
pharmacologic anti-inflammatory mechanism of topical corticosteroids;
the cited case reports specifically document improvement in the
erythema component of the inflammatory phenotype.
evidence:
- reference: PMID:40761190
reference_title: "Successful treatment of ulerythema ophryogenes with pulsed dye laser: a case report."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Pulsed dye laser treatment appears to be a safe and effective
treatment for the erythema and alopecia symptoms associated with
this refractory condition.
explanation: Confirms the laser's effect is specifically on the erythema (vascular) component of the perifollicular inflammatory phenotype.
evidence:
- reference: PMID:40761190
reference_title: "Successful treatment of ulerythema ophryogenes with pulsed dye laser: a case report."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Pulsed dye laser treatment appears to be a safe and effective treatment
for the erythema and alopecia symptoms associated with this refractory
condition.
explanation: Case report demonstrates pulsed dye laser efficacy for ulerythema ophryogenes erythema and alopecia.
- reference: PMID:11260551
reference_title: "Laser treatment of atrophoderma vermiculata."
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
We report successful treatment of 2 patients by means of the carbon
dioxide and 585 nm pulsed dye lasers.
explanation: Case series reports successful laser treatment of atrophoderma vermiculatum.
- name: Genetic Counseling
description: >-
Genetic counseling is appropriate given the heterogeneous inheritance
across KPA variants (autosomal recessive LRP1, X-linked recessive MBTPS2
KFSD, and rarer autosomal dominant familial forms).
treatment_term:
preferred_term: Genetic Counseling
term:
id: NCIT:C15240
label: Genetic Counseling
notes: >-
This root entry curates the KPA umbrella and fully curates two of its three
principal subtypes (keratosis pilaris atrophicans faciei/ulerythema
ophryogenes and atrophoderma vermiculatum). The third subtype, keratosis
follicularis spinulosa decalvans (KFSD, MBTPS2-related), already has its own
complete dismech entry at kb/disorders/Keratosis_Follicularis_Spinulosa_Decalvans.yaml
(whose parents already list "Keratosis pilaris atrophicans"); it is
cross-referenced here as a has_subtypes entry rather than duplicated. The
association between ulerythema ophryogenes/keratosis pilaris atrophicans
faciei and the RASopathies (cardiofaciocutaneous and Noonan syndrome) is
documented as a phenotypic overlap, not as KPA being classified as a
RASopathy itself (KPA is not RAS-MAPK-driven as a primary disease and is not
a member of kb/groupings/RASopathies.yaml); see the "RAS-MAPK Pathway
Dysregulation (RASopathy Context)" pathophysiology node and the
RASopathy-associated genetic entry above.
Keratosis pilaris atrophicans (KPA) is best treated as a clinically defined, genetically heterogeneous spectrum, not as one molecular disease. Its shared sequence is follicular keratin plugging and perifollicular erythema/inflammation followed by follicular destruction, atrophy, scarring, and permanent hair loss. The conventional forms are (1) keratosis pilaris atrophicans faciei (KPAF), often equated with ulerythema ophryogenes (UO); (2) atrophoderma vermiculatum/vermiculata (AV); and (3) keratosis follicularis spinulosa decalvans (KFSD). Boundaries overlap, and some classifications distinguish KPAF from UO more narrowly by facial distribution. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5)
Only X-linked KFSD has a well-supported recurrent molecular cause, MBTPS2. UO is strongly enriched in RAS/MAPK disorders but an isolated UO diagnosis does not imply that a RASopathy gene is causal. AV remains largely a clinicopathologic diagnosis with uncertain genetic architecture. Most therapeutic evidence consists of case reports or small uncontrolled series; no KPA-specific randomized trial was identified.
| Entity | Defining phenotype / distribution | Onset / course | Inheritance / genetic evidence | Suggested HPO terms | Key diagnostics | Evidence-supported treatment | Evidence limitations |
|---|---|---|---|---|---|---|---|
| Umbrella keratosis pilaris atrophicans (KPA) | Follicular keratotic papules with perifollicular erythema progressing to fibrosis/atrophy, scarring, and permanent hair loss; umbrella grouping that includes UO/KPA faciei, atrophoderma vermiculatum, and KFSD (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3) | Usually begins in infancy or childhood; several reports note progression until puberty then relative stabilization, with permanent residual alopecia/scarring possible (stojanovic2015overlapbetweenulerythema pages 1-3, stojanovic2015overlapbetweenulerythema pages 5-7) | Disease-group term rather than a single molecular entity; genetic architecture heterogeneous. Established monogenic cause exists for KFSD via MBTPS2, but isolated KPA umbrella diagnosis does not map to one confirmed causal gene in the retrieved evidence (stojanovic2015overlapbetweenulerythema pages 5-7, bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2) | Follicular hyperkeratosis; Alopecia; Eyebrow alopecia; Cicatricial alopecia; Facial erythema; Cutaneous atrophy | Primarily clinical pattern recognition plus subtype-specific histopathology when scarring alopecia or overlap is present; biopsy may show dilated keratin-plugged follicles, perifollicular inflammation, and fibrosis (stojanovic2015overlapbetweenulerythema pages 1-3, stojanovic2015overlapbetweenulerythema pages 5-7) | Symptomatic and subtype-directed: keratolytics, topical retinoids, topical corticosteroids, oral retinoids in selected inflammatory disease, and laser procedures in case reports/small series (stojanovic2015overlapbetweenulerythema pages 5-7, nimgaonkar2022ulerythemaophryogenesin pages 3-4, bari2017atrophodermavermiculataa pages 1-3) | No unified diagnostic criteria, no prevalence estimates, and no umbrella-level randomized trials identified; evidence dominated by case reports/series (stojanovic2015overlapbetweenulerythema pages 1-3, bari2017atrophodermavermiculataa pages 1-3) |
| KPA faciei / ulerythema ophryogenes (UO) | Inflammatory keratotic papules and erythema beginning in the lateral eyebrows, spreading medially; may extend to cheeks and less often forehead/scalp; leads to eyebrow alopecia/scarring (stojanovic2015overlapbetweenulerythema pages 3-5, jansen2003atrophodermiavermiculatacase pages 1-3, nimgaonkar2022ulerythemaophryogenesin pages 1-3) | Begins at birth or soon after / early infancy; often progresses through childhood and may improve after puberty, but scarring can leave permanent hair loss (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3, nimgaonkar2022ulerythemaophryogenesin pages 1-3) | Familial cases reported, often described as autosomal dominant with variable penetrance; strong syndromic association with RAS/MAPK disorders (Noonan, CFC, related syndromes), but retrieved evidence supports association rather than a single established cause for isolated UO. In CFC, UO occurred in 90% (55/61) of mutation-positive individuals; MAP3K1-associated Swyer syndrome case also reported (stojanovic2015overlapbetweenulerythema pages 1-3, siegel2011dermatologicalfindingsin pages 1-3, nimgaonkar2022ulerythemaophryogenesin pages 1-3) | HP:0000204 Eyebrow sparse; keratosis pilaris; facial erythema; scarring alopecia; madarosis | Clinical diagnosis; consider evaluation for syndromic features/RASopathy if dysmorphism, cardiac disease, developmental findings, or widespread ectodermal findings are present. Histology in overlap disease shows keratin plugging, infundibular atrophy, lymphocytic perifollicular infiltrates, fibrosis (stojanovic2015overlapbetweenulerythema pages 1-3, siegel2011dermatologicalfindingsin pages 1-3) | Topical retinoids, keratolytics (urea/lactic acid/salicylic acid), low-potency topical steroids used symptomatically; limited response reported in a MAP3K1 case. For erythematous disease, a cited 595-nm pulsed-dye laser series (n=10) achieved complete resolution in 3 and >75% improvement in 7, mainly reducing erythema (nimgaonkar2022ulerythemaophryogenesin pages 3-4, nimgaonkar2022ulerythemaophryogenesin pages 1-3) | Evidence mainly case reports and small uncontrolled laser series; effect on restoring eyebrow hair appears limited once scarring is established; causation for isolated UO remains uncertain in retrieved sources (nimgaonkar2022ulerythemaophryogenesin pages 3-4, nimgaonkar2022ulerythemaophryogenesin pages 1-3) |
| Atrophoderma vermiculatum / atrophoderma vermiculata | Symmetric follicular erythematous papules of cheeks, often preauricular, evolving into pitted reticulated “worm-eaten” / “honey-combed” atrophy and scarring (stojanovic2015overlapbetweenulerythema pages 3-5, bari2017atrophodermavermiculataa pages 1-3) | Usually childhood onset; generally slow progressive worsening (bari2017atrophodermavermiculataa pages 1-3) | Considered within KPA spectrum, but isolated AV causal genetics remain uncertain in retrieved evidence. Older reports mention possible chromosomal associations (e.g., 18p deletion), but no firmly established recurrent monogenic cause was retrieved here (jansen2003atrophodermiavermiculatacase pages 1-3, bari2017atrophodermavermiculataa pages 1-3) | Cutaneous atrophy; Facial scar; Follicular hyperkeratosis; Cheek lesion | Clinical morphology plus histopathology when needed: early keratotic follicular plugging/perifollicular inflammation; later follicular and sebaceous gland atrophy with dermal fibrosis (bari2017atrophodermavermiculataa pages 1-3) | Case-report support only for topical tretinoin and 35% trichloroacetic acid chemical peeling with partial response; literature cited in review/case reports also mentions CO2 laser, 585-nm pulsed-dye laser, dermabrasion, cryotherapy, and isotretinoin for inflammatory activity (bari2017atrophodermavermiculataa pages 1-3) | No curative therapy identified; very sparse evidence base, almost entirely single-patient reports; long-term benefit of cosmetic procedures hard to judge (bari2017atrophodermavermiculataa pages 1-3) |
| Keratosis follicularis spinulosa decalvans (KFSD) | Diffuse follicular hyperkeratosis with progressive cicatricial alopecia of scalp, eyebrows, and eyelashes; may include facial erythema, keratosis pilaris on trunk/extremities, photophobia, and ocular inflammation (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 4-5, alessandrini2021theroleof pages 1-2) | Infancy or childhood onset; scalp alopecia typically progresses through childhood/early adolescence; some reports note progression until puberty with permanent scarring alopecia (stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5, alessandrini2021theroleof pages 1-2) | Established MBTPS2-related disorder with X-linked inheritance; study of 15 affected males from 13 unrelated families identified 11 missense mutations and genotype-phenotype correlations. Variant c.1523A>G p.(Asn508Ser) caused mild KFSDX in three unrelated families (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2, bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8, bornholdt2013genotype–phenotypecorrelationsemerging pages 2-3) | HP:0002556 Scarring alopecia; HP:0002209 Keratosis pilaris; HP:0000656 Eyelash alopecia; HP:0000204 Eyebrow sparse; photophobia | Diagnosis is clinical plus pathology; trichoscopy can show perifollicular hyperkeratosis, absent follicular ostia, tufted folliculitis/elongated vessels, yellow dots with dystrophic hairs. Histopathology shows decreased sebaceous glands and follicular units with diffuse fibrosis (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 4-5) | Best evidence is low-level but more specific than other KPA forms: keratolytics plus isotretinoin 0.3 mg/kg/day for 6 months produced complete facial resolution and scalp improvement in one report; subsequent minoxidil 5% twice daily increased hair density. Acitretin improved follicular ichthyosis/eyelash regrowth in related MBTPS2 disease but not established alopecia (alessandrini2021theroleof pages 3-4, ming2009ichthyosisfollicularisalopecia pages 1-3) | Despite established gene causation, treatment evidence remains limited to case reports/reviews; no disease-specific controlled trials identified; irreversible scarring limits hair recovery even with treatment (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 4-5) |
Table: This compact table summarizes the keratosis pilaris atrophicans spectrum and separates clinically defined entities from the genetically established MBTPS2-associated KFSD subtype. It is useful for disease knowledge-base curation because it aligns phenotype, course, genetics, diagnostics, treatment evidence, and uncertainty in one place.
This report synthesizes aggregated disease-level literature, including family studies, case reports, reviews, and a mutation-positive syndromic cohort. It is not derived from individual EHR records.
KPA is a congenital/developmental follicular keratinization spectrum. The proximal lesion is abnormal keratinization in and around the pilosebaceous follicle, followed by plugging, inflammation, follicular atrophy, and fibrosis. (stojanovic2015overlapbetweenulerythema pages 1-3, jansen2003atrophodermiavermiculatacase pages 1-3)
No reproducible modifier genes, protective variants, founder alleles, carrier frequency, or population allele-frequency estimates were identified. Reported MBTPS2 variants should be checked individually in current ClinVar and gnomAD releases; the source studies do not supply ACMG/AMP classifications or population frequencies. The disease variants described are constitutional/germline, not somatic.
No toxin, infection, radiation exposure, occupation, diet, smoking, alcohol, exercise pattern, or lifestyle behavior is established as causal. No validated genetic or environmental protective factor exists. Dryness or irritation may plausibly accentuate follicular roughness, but evidence that these alter the scarring natural history is lacking. Accordingly, a formal gene–environment interaction has not been demonstrated.
UO commonly begins at birth or soon afterward; KFSD begins in infancy or childhood, with scalp disease becoming conspicuous in childhood or early adolescence; AV generally begins in childhood. Severity is variable. UO and KFSD often progress until puberty and then stabilize or become less inflammatory, but alopecia and atrophy remain. (stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5, nimgaonkar2022ulerythemaophryogenesin pages 1-3, bari2017atrophodermavermiculataa pages 1-3)
Reliable frequencies for isolated KPA manifestations are unavailable. The strongest quantitative datum is syndromic: UO in 90% (55/61) of mutation-positive CFC patients, which must not be generalized to isolated KPA. (siegel2011dermatologicalfindingsin pages 1-3)
No validated KPA-specific EQ-5D, SF-36, PROMIS, or dermatology-quality-of-life cohort was identified. The principal expected burden is visible facial/scalp scarring, eyebrow/eyelash loss, cosmetic disfigurement, and—in KFSD with ocular disease—photophobia. AV has explicitly been described as a rare “disfiguring” condition, but this is descriptive rather than instrument-based evidence. (bari2017atrophodermavermiculataa pages 1-3)
MBTPS2 encodes an endoplasmic-reticulum/Golgi membrane zinc metalloprotease, site-2 protease (S2P), required for regulated intramembrane proteolysis. After site-1 cleavage, S2P releases membrane-bound transcription factors controlling sterol homeostasis, lipid metabolism, ER-stress responses, and differentiation, including SREBP, ATF6, and OASIS-family proteins. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2, lim2021omicsprofilingof pages 2-4)
Pathogenic substitutions cluster in transmembrane domains. Changes near the catalytic site reduce activity most severely; residual activity correlates with phenotype. N- or C-terminal variants retaining more activity tend to produce milder disease, whereas transmembrane-domain 6–8 hotspots can eliminate approximately two-thirds of catalytic activity and cause severe developmental/ichthyotic phenotypes. p.Asn508Ser is associated with mild KFSD and progressive alopecia. Female expression is influenced by X-chromosome inactivation. (bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8)
No dominant-negative mechanism is established; the evidence supports partial loss of catalytic function/hypomorphic dysfunction. Whole-gene deletions, recurrent splice variants, repeat expansions, mitochondrial variants, and disease-specific epigenetic abnormalities were not established.
KPA is not infectious or transmissible, and no microbial trigger is recognized. There is no evidence for pollution, toxins, ultraviolet exposure, occupational exposure, diet, smoking, alcohol, or exercise as causal factors. Standard skin care may reduce roughness and irritation but is supportive rather than disease-preventing. CTD-style chemical associations, validated gene–environment effects, and exposure-response data are absent.
The principal profiling study used primary skin fibroblasts from four controls, three MBTPS2-osteogenesis-imperfecta patients, and two MBTPS2-IFAP/KFSD patients, with RNA sequencing, lipid analysis, electron microscopy, and immunofluorescence. The dermatologic group included p.Arg429His and p.Asn508Ser. This establishes pathway-level dysfunction but is underpowered for a KFSD-specific molecular signature. No KPA-specific single-cell atlas, spatial transcriptomic dataset, proteomic signature, metabolomic biomarker, organoid, or CRISPR screen was identified. (lim2021omicsprofilingof pages 2-4)
The primary organ is skin, specifically the pilosebaceous unit and hair follicles.
Suggested UBERON labels are skin of face, cheek, eyebrow, eyelid/eyelash region, scalp, hair follicle, sebaceous gland, cornea, and conjunctiva. Disease is generally bilateral and symmetric in UO/AV; focal or patchy scalp alopecia can occur in KFSD. (stojanovic2015overlapbetweenulerythema pages 3-5, stojanovic2015overlapbetweenulerythema pages 1-3)
Onset is congenital, neonatal, or early pediatric rather than adult-acquired. The onset is insidious and chronic. Active stages feature follicular papules and erythema; intermediate disease adds follicular atrophy and hair loss; advanced disease contains established fibrosis, absent follicular ostia, and irreversible scarring. UO/KFSD often progress until puberty and subsequently stabilize, while AV usually worsens slowly. Inflammation can remit spontaneously or with treatment, but destroyed follicles do not regenerate. (stojanovic2015overlapbetweenulerythema pages 1-3, stojanovic2015overlapbetweenulerythema pages 5-7, nimgaonkar2022ulerythemaophryogenesin pages 1-3, bari2017atrophodermavermiculataa pages 1-3)
The critical therapeutic window is therefore the active inflammatory stage before fibrosis, although this inference has not been tested prospectively.
No robust prevalence, incidence, geographic distribution, ethnicity effect, carrier frequency, founder effect, anticipation, germline-mosaicism rate, or consanguinity association was found. “Rare” or “exceedingly rare” is currently more defensible than a cases-per-100,000 estimate. There is no established sex imbalance for the umbrella spectrum; male predominance/severity applies chiefly to X-linked KFSD.
Diagnosis starts with age of onset, distribution, inflammatory activity, scarring, family history, and associated ocular or syndromic findings. There are no validated standardized criteria or circulating biomarkers. Routine blood/urine tests and radiologic imaging are not diagnostic.
Trichoscopy in KFSD can show diffuse perifollicular hyperkeratosis, absent follicular ostia, tufting, elongated vessels, yellow dots, and dystrophic eyebrow/eyelash hairs. Evidence is very limited—the 2021 report described itself as the first trichoscopic evaluation. (alessandrini2021theroleof pages 3-4, alessandrini2021theroleof pages 4-5)
Histopathology: early lesions show dilated keratin-filled follicles and perifollicular lymphocytes. Progressive lesions show infundibular atrophy, reduced sebaceous glands and follicular units, and perifollicular or diffuse fibrosis. AV similarly progresses from follicular plugging/inflammation to pilosebaceous atrophy and dermal fibrosis. (stojanovic2015overlapbetweenulerythema pages 1-3, alessandrini2021theroleof pages 4-5, bari2017atrophodermavermiculataa pages 1-3)
Differentials include ordinary nonatrophic keratosis pilaris; keratosis pilaris rubra; folliculitis decalvans; lichen planopilaris; frontal fibrosing alopecia; IFAP syndrome; keratitis–ichthyosis–deafness syndrome; atrichia with papular lesions; hereditary mucoepithelial dystrophy; acne or varicella scars; focal dermal hypoplasia; and other varioliform atrophodermas. Loss of follicular ostia and fibrosis distinguish cicatricial disease; eyelash/scalp scarring favors KFSD, whereas lateral eyebrow-predominant disease favors UO and reticulated cheek pits favor AV. (alessandrini2021theroleof pages 4-5)
No population, newborn, or carrier-screening program exists. Cascade testing is appropriate only after a familial pathogenic variant is established.
KPA is not known to reduce survival or life expectancy; disease-specific mortality has not been reported. Morbidity is dermatologic and cosmetic, with photophobia/ocular inflammation adding functional burden in KFSD. The active inflammatory component may improve after puberty or treatment, but established alopecia and pitted atrophy are generally permanent. (stojanovic2015overlapbetweenulerythema pages 5-7, nimgaonkar2022ulerythemaophryogenesin pages 1-3)
Poorer outcome is expected with extensive scalp involvement, eyelash loss, prolonged inflammation, or delayed control before fibrosis. These are clinically plausible prognostic features, not validated predictors. No prognostic molecular biomarker or survival model exists.
There is no curative or regulatory-approved disease-modifying therapy. Management aims to reduce plugging and inflammation before scarring, treat ocular disease, and improve appearance.
Potential adverse effects include irritant dermatitis from acids/retinoids, steroid atrophy, retinoid teratogenicity and mucocutaneous/laboratory toxicity, minoxidil irritation/hypertrichosis, and laser-associated pain, pigment alteration, or scarring. No KPA pharmacogenomic guidance exists. There is no gene, cell, RNA, CRISPR, targeted kinase, or immunotherapy in clinical use.
ClinicalTrials.gov searching retrieved studies for ordinary keratosis pilaris—including diode/Nd:YAG/thulium laser, emollient, and cosmetic interventions—but none was established as enrolling KPA/UO/AV/KFSD specifically. These should not be represented as disease-specific KPA trials.
Primary prevention is unavailable because the disease is inherited/developmental; vaccines, prophylactic drugs, and public-health/environmental interventions are not applicable. Secondary/tertiary prevention consists of early recognition, minimizing follicular inflammation before fibrosis, ophthalmologic surveillance when indicated, and screening syndromic UO patients for associated RASopathy manifestations. A report specifically advocated improved UO recognition in RASopathy patients to permit intervention before permanent scarring. (nimgaonkar2022ulerythemaophryogenesin pages 3-4)
For molecularly confirmed families, genetic counseling should cover subtype-specific inheritance, variable expression, recurrence risk, cascade testing, and reproductive options, including prenatal or preimplantation testing when desired. Females carrying an MBTPS2 variant may be mildly affected or nonpenetrant. (bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2)
No verified naturally occurring KPA, UO, AV, or KFSD orthologous syndrome was identified in companion animals, livestock, or wildlife. Consequently, no breed/VBO annotation, veterinary prevalence, zoonotic potential, or cross-species transmission applies. MBTPS2 is evolutionarily conserved, but conservation alone is not evidence of a natural veterinary counterpart.
No validated mouse, rat, zebrafish, Drosophila, or other organismal model was found that demonstrably reproduces the human combination of follicular keratosis and progressive cicatricial alopecia. The most directly relevant experimental systems are patient-derived dermal fibroblasts carrying MBTPS2 variants. These support defective S2P-dependent transcription-factor activation and permit transcriptomic/lipid/ER-stress assays, but fibroblasts do not reproduce hair-follicle architecture, keratin plugging, immune–epithelial interactions, or scarring alopecia. (lim2021omicsprofilingof pages 2-4)
Future models should use variant-specific knock-in animals, human hair-follicle organoids, or isogenic iPSC-derived keratinocyte–sebocyte–fibroblast systems. Applications would include mapping SREBP/ATF6/OASIS defects to follicular differentiation, defining inflammatory-to-fibrotic transitions, and testing whether early pathway correction prevents permanent follicular loss.
The 2023–2024 literature did not materially change KPA-specific molecular diagnosis or treatment. The most informative contemporary evidence remains: patient-fibroblast molecular profiling (2021), trichoscopy plus a dose-specific KFSD treatment report (2021), and the MAP3K1-associated UO case with a summary of laser evidence (2022). The major current interpretation is therefore conservative: MBTPS2 testing is justified for KFSD; UO should trigger assessment for a RASopathy when systemic clues are present; and early anti-keratinizing/anti-inflammatory therapy is rational but unproven to prevent scarring. (lim2021omicsprofilingof pages 2-4, siegel2011dermatologicalfindingsin pages 1-3, alessandrini2021theroleof pages 3-4, nimgaonkar2022ulerythemaophryogenesin pages 3-4)
PMIDs were not consistently exposed in the retrieved records; DOI URLs and publication dates are therefore supplied rather than inventing unverified PMID values. Before production ingestion, identifiers—including MONDO, HPO IDs, HGNC ID for MBTPS2, current ClinVar assertions, and ICD mappings—should be programmatically validated against their current releases.
References
(stojanovic2015overlapbetweenulerythema pages 3-5): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.
(stojanovic2015overlapbetweenulerythema pages 1-3): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.
(alessandrini2021theroleof pages 4-5): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.
(stojanovic2015overlapbetweenulerythema pages 5-7): Slobodan Stojanović, Nada Vučković, and Marina Jovanović. Overlap between ulerythema ophryogenes and keratosis follicularis spinulosa decalvans: a case report. Serbian Journal of Dermatology and Venereology, 7:129-138, Sep 2015. URL: https://doi.org/10.1515/sjdv-2015-0012, doi:10.1515/sjdv-2015-0012. This article has 1 citations.
(bornholdt2013genotype–phenotypecorrelationsemerging pages 1-2): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.
(nimgaonkar2022ulerythemaophryogenesin pages 3-4): Ila Nimgaonkar, Marielle Jamgochian, David M. Milgraum, Amy S. Pappert, and Sandy S. Milgraum. Ulerythema ophryogenes in association with map3k1-mutated swyer syndrome. Jul 2022. URL: https://doi.org/10.1016/j.jdcr.2022.05.008, doi:10.1016/j.jdcr.2022.05.008. This article has 2 citations.
(bari2017atrophodermavermiculataa pages 1-3): Arfan ul Bari. Atrophoderma vermiculata: a rare disfiguring condition. Journal of Pakistan Association of Dermatologists, 13(4):208-210, Jan 2017. URL: https://doi.org/10.66344/jpad.v13i4.765, doi:10.66344/jpad.v13i4.765. This article has 1 citations.
(jansen2003atrophodermiavermiculatacase pages 1-3): T. Jansen, C. Sander, and P. Altmeyer. Atrophodermia vermiculata: case report and review of the literature. Journal of the European Academy of Dermatology and Venereology, 17:70-72, Jan 2003. URL: https://doi.org/10.1046/j.1468-3083.2003.00517.x, doi:10.1046/j.1468-3083.2003.00517.x. This article has 15 citations and is from a domain leading peer-reviewed journal.
(nimgaonkar2022ulerythemaophryogenesin pages 1-3): Ila Nimgaonkar, Marielle Jamgochian, David M. Milgraum, Amy S. Pappert, and Sandy S. Milgraum. Ulerythema ophryogenes in association with map3k1-mutated swyer syndrome. Jul 2022. URL: https://doi.org/10.1016/j.jdcr.2022.05.008, doi:10.1016/j.jdcr.2022.05.008. This article has 2 citations.
(siegel2011dermatologicalfindingsin pages 1-3): D.H. Siegel, J. McKenzie, I.J. Frieden, and K.A. Rauen. Dermatological findings in 61 mutation‐positive individuals with cardiofaciocutaneous syndrome. British Journal of Dermatology, 164:no-no, Jan 2011. URL: https://doi.org/10.1111/j.1365-2133.2010.10122.x, doi:10.1111/j.1365-2133.2010.10122.x. This article has 123 citations and is from a highest quality peer-reviewed journal.
(alessandrini2021theroleof pages 3-4): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.
(alessandrini2021theroleof pages 1-2): Aurora Alessandrini, Giancarlo Brattoli, Bianca Maria Piraccini, Ambra Di Altobrando, and Michela Starace. The role of trichoscopy in keratosis follicularis spinulosa decalvans: case report and review of the literature. Skin Appendage Disorders, 7:29-35, Oct 2021. URL: https://doi.org/10.1159/000510525, doi:10.1159/000510525. This article has 11 citations and is from a peer-reviewed journal.
(bornholdt2013genotype–phenotypecorrelationsemerging pages 7-8): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.
(bornholdt2013genotype–phenotypecorrelationsemerging pages 2-3): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.
(ming2009ichthyosisfollicularisalopecia pages 1-3): Andrew Ming, Rudolf Happle, Karl‐Heinz Grzeschik, and Gayle Fischer. Ichthyosis follicularis, alopecia, and photophobia (ifap) syndrome due to mutation of the gene mbtps2 in a large australian kindred. Pediatric Dermatology, 26:427-431, Jul 2009. URL: https://doi.org/10.1111/j.1525-1470.2009.00946.x, doi:10.1111/j.1525-1470.2009.00946.x. This article has 22 citations and is from a peer-reviewed journal.
(bornholdt2013genotype–phenotypecorrelationsemerging pages 3-4): Dorothea Bornholdt, T. Prescott Atkinson, Bakar Bouadjar, Benoit Catteau, Helen Cox, Deepthi De Silva, Judith Fischer, Chalukya N. Gunasekera, Smaïl Hadj-Rabia, Rudolf Happle, Muriel Holder-Espinasse, Elke Kaminski, Arne König, André Mégarbané, Hala Mégarbané, Ulrike Neidel, Frank Oeffner, Vinzenz Oji, Amy Theos, Heiko Traupe, Anders Vahlquist, Bregje W. van Bon, Marie Virtanen, and Karl-Heinz Grzeschik. Genotype–phenotype correlations emerging from the identification of missense mutations in mbtps2. Human Mutation, 34:n/a-n/a, Apr 2013. URL: https://doi.org/10.1002/humu.22275, doi:10.1002/humu.22275. This article has 48 citations and is from a domain leading peer-reviewed journal.
(lim2021omicsprofilingof pages 2-4): Pei Jin Lim, Severin Marfurt, Uschi Lindert, Lennart Opitz, Timothée Ndarugendamwo, Pakeerathan Srikanthan, Martin Poms, Martin Hersberger, Claus-Dieter Langhans, Dorothea Haas, Marianne Rohrbach, and Cecilia Giunta. Omics profiling of s2p mutant fibroblasts as a mean to unravel the pathomechanism and molecular signatures of x-linked mbtps2 osteogenesis imperfecta. Frontiers in Genetics, May 2021. URL: https://doi.org/10.3389/fgene.2021.662751, doi:10.3389/fgene.2021.662751. This article has 7 citations and is from a peer-reviewed journal.
Checked with linkml-reference-validator 0.2.1.
| Outcome | Count |
|---|---|
| References checked | 9 |
| Resolved | 9 |
| Unresolved (possible confabulation) | 0 |
| Unverifiable | 0 |
| References weighed for topical relevance | 9 |
| On topic | 3 |
| Off topic | 1 |
These identifiers resolve, so they are not fabrications, but the records they resolve to share almost none of this report's vocabulary. That is a clue and not a verdict - a paper can be relevant in ways its title and abstract do not spell out - so read them before deciding:
DOI:10.66344/jpad.v13i4.765 (5 mentions) - Atrophoderma vermiculata: A rare disfiguring conditionWeighed against this report's own most characteristic terms: disease, kfsd, gene, clinical, follicular, genetic, scarring, variant, alopecia, molecular, loss, inflammation, fibrosis, atrophy, mbtps2, established, keratosis, treatment, scalp, eyelash.
All extracted references resolved successfully. Resolving is not the same as being relevant, though - see the references listed above as possibly off topic.