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Genetic and Rare Diseases Information Center (GARD)

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Exogenous ochronosis


Other Names for this Disease

  • Ochronosis, acquired
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Overview

Exogenous ochronosis refers to the bluish-black discoloration of certain tissues, such as the ear cartilage, the ocular (eye) tissue, and other body locations when it is due to exposure to various substances.[1] It has been reported most commonly with topical application of hydroquinones to the skin. The discoloration may be caused by an effect on tyrosinase (an enzyme located in melanocytes, which are skin cells that produce pigment), or by inhibiting homogentisic acid oxidase, resulting in the accumulation and deposition of homogentisic acid (HGA) in cartilage. The discoloration is often permanent, but when exogenous ochronosis is caused by topical hydroquinones, carbon dioxide lasers and dermabrasion have been reported to be helpful.[2] Exogenous ochronosis is different from hereditary ochronosis, which is an inherited condition that occurs with alkaptonuria.
Last updated: 2/10/2011

References

  1. Craig G Burkhart, Craig N Burkhart. Ochronosis. eMedicine. April 9, 2010; http://emedicine.medscape.com/article/1104184-overview. Accessed 2/6/2011.
  2. Joseph F Merola, Shane Meehan, Ruth F Walters, Lance Brown. Dermatology Online Journal. October 2008; 14(10):6. http://dermatology.cdlib.org/1410/allarticles/articles/article06.html. Accessed 2/10/2011.
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Other Names for this Disease
  • Ochronosis, acquired
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.