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What is Ichthyosis Hystrix?

Ichthyosis hystrix is a form of epidermal nevus. Epidermal nevus is the clinical term for disorders in which the hyperkeratosis (thickening of the outer layer of skin) occurs in linear and swirling patterns within typically larger areas of uninvolved, normal skin. They are mosaic skin disorders caused by several different genes (for more information see FIRST’s information on epidermal nevi). The term ‘mosaic’ indicates that only some of the cells in the body harbor the mutation. In some instances, mosaic disorders are heritable (for more information, request FIRST’s publications, Ichthyosis: the Genetics of its Inheritance and epidermal nevi).

As more information for our “Patient Perspective” section of  Ichthyosis Hystrix becomes available, we will provide updates. Please refer to a Clinician’s Perspective for Ichthyosis Hystrix Syndrome.

1. Richardson EF, Lee JB, Hyde PH et al. A novel mutation and large size polymorphism affecting the V2 domain of keratin 1 in an African-American family with severe diffuse palmoplantar keratoderma of the Ichthyosis Hystrix Curth-Macklin Type. J. Invest. Derm. 2006; 126:79-84.
2. van Geel M1, van Steensel MA, Küster W, et al. HID and KID syndromes are associated with the same connexin 26 mutation. Br J Dermatol. 2002;146:938-42.
3. Biswas P, De A, Sendur S, Nag F, et al. A case of ichthyosis hystrix: unusual manifestation of this rare disease. Indian J Dermatol. 2014;59:82-84.
4. Wang WH, Song SJ, Zhang L et al. Disturbed keratin expression and distinct genotype of ichthyosis hystrix Lambert type. Eur J Dermatol 2010;20:567-572.

Other Names: Ichthyosis hystrix, Curth-Macklin type
OMIM: 146590
Inheritance: autosomal dominant
Incidence: very rare
Key Findings:
  • Skin: Very thick, warty hyperkeratosis resembling spines, may be diffuse or localized to elbows, knees and other regions. Palms usually severely involved, often in striate pattern.
  • Nail: May be dystrophic.
Associated Findings:
  • Usually none.
Age at First Appearance: Variable – from birth or during infancy or childhood.
Longterm Course: Life-long, but may fluctuate in severity.
Diagnostic Tests: Genetic testing (definitive). Characteristic findings in histopathology or electron microscopy of affected skin.
Abnormal Gene: KRT1 (keratin 1).

Additional Resources:

This information is provided as a service to patients and parents of patients who have ichthyosis. It is not intended to supplement appropriate medical care, but instead to complement that care with guidance in practical issues facing patients and parents. Neither FIRST, its Board of Directors, Medical & Scientific Advisory Board, Board of Medical Editors nor Foundation staff and officials endorse any treatments or products reported here. All issues pertaining to the care of patients with ichthyosis should be discussed with a dermatologist experienced in the treatment of their skin disorder.

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