Clinical features of idiopathic guttate hypomelanosis in 646 subjects and association with other aspects of photoaging

Background The lesions of idiopathic guttate hypomelanosis (IGH) are commonly seen in elderly persons, although this is an often unrecognized skin disease with an obscure etiopathogenesis. The prevalence and clinical features of IGH have not yet been well studied. Objectives The purposes of this study were to evaluate the prevalence of IGH in different age groups and to determine the association of IGH with other dermatoses related to photoaging. Methods A total of 1174 subjects were examined for IGH. A detailed history was taken and general, systemic, and cutaneous examinations were carried out on the basis of clinical features. Woods lamp examination, KOH wet mounting, and/or histopathologic examination were conducted as required. Results Of 1174 subjects, 646 showed signs of IGH. The prevalence of IGH in the group of patients aged ≥40 years was 87%. This prevalence increased with advancing age. The prevalence of IGH was 54% (n = 307) among males and 56% (n = 339) among females. Sites of frequent involvement included the distal part of the lower extremity in 93% (n = 598) of cases, the distal part of the upper extremity in 91% (n = 585), the proximal part of the upper extremity in 73% (n = 474), and the proximal part of the lower extremity in 58% (n = 376). Thirty‐nine (6%) subjects also developed IGH on the face. Frequency of dermatoses related to aging was found to be significantly associated with IGH, including numerous solar lentigo [odds ratio (OR) = 5.95] and xerosis (OR = 2.40). In addition, the subjects who used “body scrubbers” were significantly more likely to have IGH lesions (OR = 1.64). Conclusions It is very likely that IGH is a phenomenon associated with the skin’s normal aging process and repeated microtrauma to skin.