Rare diseases · Sign or symptom
Hyperkeratosis
HP:0000962
What it means
Hyperkeratosis is a histopathological term defining a thickened stratum corneum and may be present in many different skin conditions, with many possible overlaps. Hyperkeratosis refers to the increased thickness of the stratum corneum, the outer layer of the skin. Hyperkeratosis is subclassified as orthokeratotic or parakeratotic. Orthokeratotic hyperkeratosis refers to the thickening of the keratin layer with preserved keratinocyte maturation, while parakeratotic hyperkeratosis shows retained nuclei as a sign of delayed maturation of keratinocytes.
Rare diseases that can present with this84
Very common80–99%
42- Acrokeratosis verruciformis of Hopf
- Alpha-N-acetylgalactosaminidase deficiency type 2
- Amelo-onycho-hypohidrotic syndrome
- Anonychia with flexural pigmentation
- Atypical Werner syndrome
- Autosomal dominant epidermolytic ichthyosis
- Autosomal dominant generalized epidermolysis bullosa simplex, intermediate form
- Bazex syndrome
- Chilblain lupus
- Chronic mucocutaneous candidiasis
- Costello syndrome
- Dermatoleukodystrophy
- Donohue syndrome
- EEC syndrome
- Epidermolytic palmoplantar keratoderma
- Erythrokeratoderma ''en cocardes''
- Erythrokeratodermia variabilis
- Fabry disease
- Familial keratoacanthoma
- Hailey-Hailey disease
- Harlequin ichthyosis
- Hereditary mucoepithelial dysplasia
- Hyperkeratosis-hyperpigmentation syndrome
- Ichthyosis hystrix of Curth-Macklin
- Insulin-resistance syndrome type A
- Keratoderma hereditarium mutilans
- Lamellar ichthyosis
- Lichen planopilaris
- Lichen planus pemphigoides
- Linear verrucous nevus syndrome
- MEDNIK syndrome
- Netherton syndrome
- Palmoplantar keratoderma-deafness syndrome
- Porokeratosis of Mibelli
- Prolidase deficiency
- Reactive arthritis
- Recessive X-linked ichthyosis
- Restrictive dermopathy
- Sialidosis type 1
- Sjögren-Larsson syndrome
- Syndromic recessive X-linked ichthyosis
- Tyrosinemia type 2
Common30–79%
24- Acquired ichthyosis
- Alopecia-contractures-dwarfism-intellectual disability syndrome
- Alpha-N-acetylgalactosaminidase deficiency type 1
- Arthrogryposis-renal dysfunction-cholestasis syndrome
- Autosomal recessive generalized epidermolysis bullosa simplex
- Cardiofaciocutaneous syndrome
- CHILD syndrome
- Chromomycosis
- Congenital panfollicular nevus
- Dowling-Degos disease
- Ectodermal dysplasia-sensorineural deafness syndrome
- Hereditary sensory and autonomic neuropathy type 1
- Hypotrichosis simplex of the scalp
- Ichthyosis follicularis-alopecia-photophobia syndrome
- Infantile digital fibromatosis
- Keratoderma hereditarium mutilans with ichthyosis
- Leprosy
- Lipoid proteinosis
- Lymphatic filariasis
- Milroy disease
- Pellagra
- Pemphigus vegetans
- Werner syndrome
- Xeroderma pigmentosum
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Epidermal hyperkeratosis
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.