Ichthyosis defines a set of inherited skin diseases
characterized by dryness of the skin accompanied by the presence of so-called squamous lesions
, which roughly resemble scales. It can affect the entire skin surface, but usually spares the face. This type of disease
often affects children. The ichthyosiform hyperkeratosis
, for example, affects primarily the palms, the soles of the feet
, and areas in folds.