Idiopathic guttate hypomelanosis: a comprehensive overview

Idiopathic guttate hypomelanosis (IGH) is a very common, acquired, and frequently ignored condition characterized by an appearance of multiple, well-circumscribed, asymptomatic, polygonal, white macules symmetrically distributed on the extensor forearms and shins. Once present, skin lesions do not increase in size with time and do not coalesce. IGH occurs in all races and skin types, especially in elderly patients over the age of 70 years. IGH appears to result from an impaired synthesis of melanin, decreased size and poor melanization of melanosomes and inadequate transfer of melanosomes from melanocytes to surrounding keratinocytes. The diagnosis of IGH is usually made clinically. Despite straightforward clinical appearance of IGH in majority of cases, several additional diagnostic procedures may be needed for confirmation of diagnosis in some less clear cases.