Idiopathic Guttate Hypomelanosis

Updated: Aug 14, 2017
  • Author: Christopher R Gorman, MD; Chief Editor: William D James, MD  more...
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Overview

Background

Idiopathic guttate hypomelanosis (IGH) is an acquired, benign leukoderma of unknown etiology. Idiopathic guttate hypomelanosis is most commonly a complaint of middle-aged, light-skinned women, but it is increasingly seen in both sexes and older dark-skinned people with a history of long-term sun exposure. See the image below.

Idiopathic guttate hypomelanosis. Courtesy of Derm Idiopathic guttate hypomelanosis. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/colour/igh1.jpg).

Idiopathic guttate hypomelanosis is a benign condition. The cause is not known, but it appears to be related to the effect of the sun on melanocytes, which makes them effete.

A variety of therapeutic methods, including topical steroids, topical retinoids, dermabrasion, cryotherapy, and minigrafting, have been used for idiopathic guttate hypomelanosis with variable success. [1]

 

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Pathophysiology

Because pigmentation of the skin is due to an integration of melanocyte and keratinocyte function, an acquired defect of the epidermal melanin unit results in the observed hypopigmentation in idiopathic guttate hypomelanosis patients. Significantly fewer dopa oxidase-positive, KIT+, and melanocytes are seen in the lesions. [2, 3] In 1967, Hamada and Saito found a 50% reduction in melanocytes.

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Epidemiology

Frequency

United States

Idiopathic guttate hypomelanosis is a very common condition to the point of being almost universal in elderly fair-skinned individuals. In 2002, a case control study of 47 renal transplant patients demonstrated a significant positive association between HLA-DQ3 and the development of idiopathic guttate hypomelanosis and a significant negative association between HLA-DR8 and the development of idiopathic guttate hypomelanosis.

International

Idiopathic guttate hypomelanosis is most common in countries with fair-skinned populations having a high degree of sun exposure.

Race

Idiopathic guttate hypomelanosis affects fair-skinned people at a younger age.

Sex

Idiopathic guttate hypomelanosis is seen far more frequently in women, beginning around the age of 30 years. However, with increasing age and sun exposure, it is found almost equally in elderly men and women. Why idiopathic guttate hypomelanosis occurs earlier in young women than in young men is unknown.

Age

Idiopathic guttate hypomelanosis is related to the lack of pigmentary protection from the sun and sun exposure rather than to age. Fair-skinned women develop this condition first; later, with increasing age and exposure to sun, both sexes seem to be equally affected.

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Prognosis

Idiopathic guttate hypomelanosis is cosmetic alone, albeit, it is indicative of cumulative sun exposure. Idiopathic guttate hypomelanosis progresses with increasing sun exposure and, to a lesser degree, with age.

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Patient Education

Progress in preventing idiopathic guttate hypomelanosis can be made by educating young women not to tan their legs.

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