What Is Acquired Ichthyosis?

This skin disorder is usually linked to an underlying condition

Dermatology Consultation. Credit: Media for Medical / Contributor / Getty Images

Ichthyosis represents a group of skin disorders which cause dry, scaly, or thick skin. There are two main types of ichthyosis –– hereditary and acquired. Most cases are hereditary, and can affect any gender or ethnicity.

Acquired cases are most often caused by an underlying disorder such as: 

Acquired ichthyosis has also been associated with the use of certain medications, such as niacinamide, Tagamet (cimetidine) and Lamprene (clofazimine). 

Acquired ichthyosis vulgaris –– also known as fish scale disease because of the pattern in which dry, dead skin accumulates –– is the most common type of acquired ichthyosis. This type of ichthyosis appears most often in adulthood and may appear any time before or after the diagnosis of a systemic condition. 

Both types of ichthyosis are considered rare, with less than 200,000 cases diagnosed in the United States each year. 

Ichthyosis Symptoms 

Acquired ichthyosis symptoms are often very similar to those of hereditary ichthyosis. Typical symptoms include:

  • Areas of rough, dry skin
  • Symmetrical scaling of the skin –– scales may be small and fine or large and thick. Dark-skinned individuals often have darker scales. A person can have multiple types of scales on their body.
  • Dry, scaly scalp
  • Overgrowth (hyperkeratosis) of the skin on the palms and soles
  • Cracked skin creases, which may crack more during dry weather
  • Keratosis pilaris (follicular hyperkeratosis), acne-like bumps, on the side of the neck, back of the upper arms, buttocks, or thighs

Scales are most common on the elbows and lower legs. Scales in these regions may also be thicker than other areas of the body on which they appear. Symptoms tend to be worse in cold, dry environments and may improve in warmer, humid climates. 

Getting a Diagnosis

A doctor can usually diagnose ichthyosis based on what your skin looks like. A skin sample (biopsy) may also be taken and examined under a microscope for changes characteristic of the disorder. Biopsies can help rule out other conditions, like eczema and dermatitis. Most often, biopsies will be taken where the skin and scales are the thickest –– like the elbows and shins. If acquired ichthyosis appears before a systemic disease is diagnosed, you will most likely need to be examined for the presence of an underlying disorder.

Treating Acquired Ichthyosis 

The severity of acquired ichthyosis usually depends on the underlying condition present.

As the systemic condition is treated, the ichthyosis generally improves. The skin affected by ichthyosis is treated by hydration with alpha-hydroxy acid lotions, such as Lac-Hydrin (ammonium lactate). Topical retinoid cream like Retin-A (tretinoin), may also be used. Scales and skin buildup can be reduced with salicylic acid. Whichever treatment you use, it's important to keep the skin hydrated with a lotion that won't evaporate. If you have acquired ichthyosis, make sure to consistently follow-up with your dermatologist and any other specialists monitoring any underlying conditions. 


"Types of Ichthyosis." About Ichthyosis. Foundation for Ichthyosis & Related Skin Types. 11 Jul 2008

Hereditary and Acquired Ichthyosis Vulgaris. Medscape. (2015)

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