Ichthyoses describe a group of disorders of cornification in which the epidermis differentiates abnormally, leading to generalized scaling of the skin. Ichthyosis is derived from the Greek word for fish, “ichthys.” Ichthyosis vulgaris is the most common of these conditions and often presents in early childhood during the first year of life. It is inherited in an autosomal-dominant pattern. Skin is dry and scaly over the entire body, although the antecubital and popliteal fossa may be uninvolved. The scalp may be involved as well. Atopy and keratosis pilaris may be associated. By adulthood, symptoms tend to abate.
X-linked ichthyosis is an X-linked recessive trait, in which males are affected and mothers are carriers. The condition is caused by a deficiency of steroid sulfatase. This deficiency can result in low levels of estrogen during pregnancy in the mother of an affected fetus, hampering labor progression, and often requiring C-section. Children usually present before 3 months of age. Scales are large and dark. The antecubital and popliteal fossa are usually spared. The neck almost always is involved, coining the term “dirty neck disease.” Corneal opacities are present upon ophthalmologic examination. There is an increased risk of cryptorchidism and testicular cancer. Skin symptoms tend to worsen into adulthood.
Lamellar ichthyosis generally occurs at birth with a striking collodion-type membrane covering the body and underlying erythroderma, which then desquamates. Ectropion is usually present as well. Resulting scales are large and gray-brown. Lamellar ichthyosis is inherited in an autosomal recessive pattern. Mutations in transglutaminase 1 (TGM1), ALOXE3, ALOX12B, and ABCA12 genes have been implicated in this disorder.
Acquired ichthyosis can appear clinically similar to ichthyosis vulgaris. It occurs in patients with systemic diseases such as Hodgkin disease, non-Hodgkin lymphoma, mycosis fungoides, multiple myeloma, hypothyroidism, sarcoidosis, AIDS, and others.
improve hyperkeratosis. Urea-containing products can be helpful. Salicylic acid may be used but merit caution in children because of salicylate toxicity. Oral and topical retinoid can be helpful in lamellar ichthyosis.
This case and photo were submitted by Dr. Bilu Martin.
Dr. Bilu Martin is a board-certified dermatologist in private practice at Premier Dermatology, MD, in Aventura, Fla. More diagnostic cases are available at mdedge.com/edermatologynews.com. To submit a case for possible publication, send an email to [email protected].