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Health Information Center


  • Cynthia M. Johnson, MA
Publication Type:



(Fish Scale Disease; Xeroderma)


Ichthyosis is a group of skin disorders that cause dryness and scaling. There are two main types:

  • Inherited—passed down in families
  • Acquired—due to certain health problems (rare)

Treatment can help manage the condition.


The inherited type is caused by a gene defect. The defect is passed from parent to child. Or the defect occurs on its own.

The acquired type may be caused by health problems or certain treatments, such as:

Risk Factors

Things that may raise the risk of this problem are:

  • Having other family members who have it
  • Having any of the health problems that may cause the acquired type


It can affect any part of the body. It is most common on the legs and arms. But it can affect other large areas of the body. Symptoms can be mild to severe and include:

  • Dry, flaking skin
  • Scaling that looks like fish scales
  • Shedding of skin layers
  • Itching
  • Scarring


The doctor will ask about symptoms, past health, and family history. A physical exam will be done. It will focus on the skin. This may be enough to make the diagnosis.

Other tests may be done to help confirm the diagnosis. They include:

  • Blood tests—to look for signs of the gene linked to this condition
  • Skin biopsy—a small sample of skin is taken and tested
Skin Biopsy.

Skin proceedurehttp://services.epnet.com/getimage.aspx?imageiid=76537653si55551723.jpgsi55551723.jpgNULLjpgsi55551723.jpgNULL\\hgfiler01a\intellect\images\si55551723.jpgNULL10NULL2008-12-102573907653_11753Copyright © Nucleus Medical Media, Inc.


There is no cure. The goal of treatment is to manage symptoms. It is also to reduce the risk of other problems. Any underlying cause will also need to be treated.

Treatment may include:

  • Lifestyle changes, such as:
    • Using non-soap cleansers
    • Removing scales with a pumice stone
  • Ointment, lotions, or creams—to keep the skin moist
  • Solutions or creams with lactic/salicylic acid or urea—to ease scaling
  • Medicines by mouth or applied to the skin, such as retinoids or calcipotriene—to treat severe symptoms


There are no current guidelines to prevent this health problem.





  • Ichthyosis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/ichthyosis.
  • Ichthyosis. DermNet NZ website. Available at: https://www.dermnetnz.org/topics/ichthyosis.
  • Newly diagnosed? Foundation for Ichthyosis & Related Skin Types website. Available at: http://www.firstskinfoundation.org/content.cfm/Ichthyosis/Newly-Diagnosed/page_id/1245.
  • Vahlquist A, Fischer J, et al. Inherited nonsyndromic ichthyoses: an update on pathophysiology, diagnosis and treatment. Am J Clin Dermatol. 2018;19(1):51-66.


  • Daniel A. Ostrovsky, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.