Ichthyosis

Ichthyosis is a family of genetic skin disorders marked by dry, thickened and scaling skin, named from the Greek word for fish because the scaling resembles fish scales. More than twenty distinct types have been identified, differing in severity, outward appearance, the specific gene involved and the pattern of inheritance, which may be autosomal dominant, autosomal recessive, X-linked or semi-dominant depending on the form. A separate, non-genetic form known as ichthyosis acquisita can develop later in life, typically in association with another underlying illness, rather than being inherited. Because the disorders share a common surface appearance but differ in cause and severity, accurate typing through clinical examination, family history and increasingly genetic testing is important for prognosis and management, which generally centers on moisturizing regimens, keratolytic agents and, for severe forms, more intensive dermatological care to reduce scaling and prevent complications such as skin infection or impaired temperature regulation.