The information in this section has been gathered from existing peer-reviewed and other literature and has been reviewed by expert dermatologists on the CSPA Medical Advisory Board.

Ichthyosis is an umbrella term referring to a grouping of over 20 different subtypes of rare genetic skin disorders characterized by dry skin that appears as dry, thickened and scaly. Ichthyosis comes from the Greek word for fish (ichthys), since it causes scaly skin similar to that of a fish. The epidermal (top) layer of the skin contains keratin proteins that accumulate to form a thick layer of hardened skin either because of decrease in the rate at which the skin sheds or because of abnormal production of proteins. This condition presents with a wide range of clinical changes from barely noticeable to very severe. Depending on the subtype there may be non-skin changes for which patients need to be monitored (see complications under the Symptoms tab).

Skin conditions included in the ichthyosis family include:

• Ichthyosis vulgaris
• X-linked ichthyosis
• Congenital ichthyosiform erythroderma, nonbullous (nbCIE)
• Epidermolytic hyperkeratosis (bullous ichthyosis, bCIE)
• Harlequin-type ichthyosis
• Ichthyosis bullosa of Siemens
• Ichthyosis hystrix, Curth-Macklin type
• Hystrix-like ichthyosis with deafness
• Lamellar ichthyosis, type 1
• Lamellar ichthyosis, type 2
• Lamellar ichthyosis, type 3
• Lamellar ichthyosis, type 4
• Lamellar ichthyosis, type 5
• Autosomal recessive congenital ichthyosis
• CHILD syndrome
• Conradi–Hünermann syndrome
• Ichthyosis follicularis with alopecia and photophobia syndrome
• Keratitis–ichthyosis–deafness syndrome
• Netherton syndrome
• Neutral lipid storage disease with ichthyosis
• Adult Refsum disease
• Ichthyosis and male hypogonadism
• Sjögren–Larsson syndrome
• Photosensitive trichothiodystrophy (IBIDS syndrome)
• Gaucher disease, type 2
• Ichthyosis acquisita