(Fish Scale Disease; Xeroderma)
Ichthyosis is a dry skin condition. There are two types:
- Inherited ichthyosis—dryness and scaling of the skin due to hereditary factors
- Acquired ichthyosis—thickening and scaling of the skin that is associated with certain medical disorders
Inherited ichthyosis is caused by a genetic defect that is passed from parent to child or that occurs on its own.
Acquired ichthyosis is relatively rare, but may be caused by any of the following:
Factors that may increase your risk of ichthyosis include:
- Family member with ichthyosis
- Certain diseases
Ichthyosis may be triggered by:
- Cold weather
- Frequent or lengthy bathing, especially in hot water
- Harsh soaps or detergents
- Soaps or lotions containing perfumes
Ichthyosis can develop on any part of the body, but most often occurs on the legs, arms, or trunk. The symptoms can vary from mild to severe. In severe cases, the condition may be disfiguring. Symptoms may include:
- Dry, flaking skin
- Scaling of skin that gives skin the appearance of fish scales
- Shedding of layers of the skin
- Itching of skin
- In severe cases, scarring and/or infection due to rubbing and scratching of scales or blisters
With certain rare types of inherited ichthyosis, symptoms:
- Appear immediately at birth
- Are extremely severe, covering the entire body
- Cause severe complications or death
You will be asked about your symptoms and medical history. A physical exam will be done. Rarely, blood tests or a may be required.
Your bodily fluids and tissues may be tested. This can be done with:
- Blood tests
- Skin biopsy
Since there is no cure for ichthyosis, treatment consists of managing the symptoms. Most treatment is aimed at keeping the skin moist. In severe cases, medication may be prescribed. For the acquired form, treating the underlying condition may also help lessen the symptoms of the ichthyosis.
Many types of moisturizing ointments, lotions, and creams are used to relieve symptoms of ichthyosis. These include:
- Petroleum jelly
- Mineral oil
- Creams, lotions, and ointments containing vitamin A
- A large variety of over-the-counter, unscented moisturizers
For ichthyosis that causes scaling:
- Solutions or creams with lactic or salicylic acid or urea may help.
- In some cases, you may be advised to wrap affected areas with a plastic or cellophane bandage after applying a moisturizing agent. Such bandages should not be used on children.
In severe cases, medications are sometimes prescribed, including:
- Retinoids to unclog pores and allow other topical medications to work better
- Antipsoriatic medications used to treat psoriasis symptoms
- Antibiotics to treat infection
- Calcineurin inhibitors applied to the skin to treat symptoms of atopic dermatitis
- Special soaps to disinfect the affected area
There are no guidelines for preventing the development of ichthyosis. However, steps to prevent this condition from getting worse include:
- Bathing less often
- Applying unscented moisturizer regularly and frequently, especially in winter
- Using only mild soap
- Harsh soaps
- Soaps with scents or perfumes
- Skin contact with detergents
- Cold, dry weather when possible
Foundation for Ichthyosis and Related Skin Types
The National Registry for Ichthyosis and Related Disorders
Canadian Dermatology Association
Ichthyosis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated April 11, 2013. Accessed January 22, 2015.
Newly diagnosed? Foundation for Ichthyosis and Related Skin Types website. Available at: http://www.firstskinfoundation.org/content.cfm/Ichthyosis/Newly-Diagnosed/page_id/1245. Accessed November 21, 2013.
Last reviewed January 2015 by Purvee S. Shah, MD; Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.