Idiopathic guttate hypomelanosis

SUMMARY Idiopathic guttate hypomelanosis is usually associated with guttate hyperkeratosis, xerosis, and lentiginosis not related to the patient's age. Histologically, hypopigmented macules show remarkably decreased melanin, decreased DOPA-oxidase activity and a decreased number of melanosomes in the melanocytes with predominance of Stages I and II and small sizes. The epidermis is always atrophic. When scales are removed by scraping, hyperkeratotic lesions show, clinically and histologically, variable degrees of hypomelanosis; thus suggesting a relationship with the hypopigmented macules. These data suggest that idiopathic guttate hypomelanosis is the result of an early aging of the skin.