What is ichthyosis?
Ichthyosis is characterized by dry or scaly and thickened skin. “Ichthy” comes from the Greek word for fish. This condition is called “ichthyosis” because the thickened skin sometimes has the appearance of fish scales.
Ichthyosis can be inherited from your parents, in which case it usually appears before your first birthday and affects you throughout life. This information will focus on inherited ichthyosis, although the disease could also occur as the result of some medical problems.
The most common signs of ichthyosis are dry scaly skin, redness, blistering, or too much skin shedding. Symptoms include itching, overheating, and pain.
Doctors may identify ichthyosis by the gene that causes it, although symptoms can usually place the disease into one of five categories:
- Ichthyosis vulgaris: mild skin scaling and dryness.
- Epidermolytic ichthyosis (previously called epidermolytic hyperkeratisis): thick, often spiny dark scales; injured skin may blister easily.
- Lamellar ichthyosis: large, platelike scales and thickening of the skin.
- Congenital ichthyosiform erythroderma: red skin and fine scales.
- Localized ichthyosis: thick or scaly skin at certain places, such as the palms of the hands and bottoms of the feet.
Ichthyosis may be either inherited or acquired. Inherited ichthyosis is usually apparent during the first year of life, often at birth, and continues to affect a person throughout life. Acquired ichthyosis may occur as the result of medical problems including hormonal, inflammatory, or malignant disorders. This fact sheet focuses on inherited ichthyosis.
There are more than 40 defective genes that can cause ichthyosis. In general, defects in more than one gene cause each clinical type of ichthyosis.
Your doctor diagnoses ichthyosis through a physical exam and by asking you questions about your health. In some cases, doctors may take blood or skin samples to diagnose the condition or identify the particular form.
There is no cure for ichthyosis. Treatment relieves symptoms and can include creams, lotions, or ointments to relieve dryness. Salt or aspirin dissolved in water, or over-the-counter lotions containing urea, may also ease scaling. For more severe cases, doctors may prescribe certain forms of vitamin A.
Ichthyosis is treated by dermatologists, who are doctors that diagnose and treat diseases of the skin, hair, and nails.
Although the genes responsible for most ichthyosis cases have been identified, there are still some people with the disease who don’t have one of these defective genes. For that reason, researchers continue to search for genes involved in the condition, as well as ways to change genes to stop the disease. Other scientists are seeking more effective treatments, such as better skin moisturizers and softeners.
In 1994, the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) funded the National Registry for Ichthyosis and Related Disorders. This registry identifies people with ichthyosis and other related disorders, to collect information about their skin disorder and how it has affected them. Although the registry is now closed to new enrollment, it continues to provide crucial information to scientists.