ABSTRACT
Dowling-Degos disease (DDD) is a genodermatosis characterized by acquired reticular hyperpigmentation in flexural sites that may associated with other cutaneous manifestations. DDD is a rare disorder usually of adult onset, although it may sometimes occur in childhood. DDD has an autosomal-dominant transmission with variable penetrance, but it can also occur sporadically. The differential diagnosis of DDD in the genital area includes other disorders that may cause hyperpigmentation such as melanosis, acanthosis nigricans, seborrheic keratosis, melanoma, bowenoid papulosis and other genodermatoses such as Galli-Galli disease, reticulate acropigmentation of Kitamura, and Peutz-Jeghers syndrome. The diagnosis of DDD is classically based on the clinical presentation and histopathological features. Dermoscopy of hyperpigmented macules shows the presence of brownish spots or reticular brownish pigmentation sometimes delimiting small, hypopigmented circles. The most notable feature of macular lesions in DDD is a striking filiform elongation of the rete ridges.
