Reticulate pigmented anomaly of the flexures, also known as Dowling-Degos disease (DDD) or Dowling-Degos syndrome, is a rare autosomal dominant pigmentary disorder characterized by progressive brown-black hyperpigmentation of the flexures that first appears in adolescence or adulthood. Pigmentation typically arises in the axillae, neck, and inframammary areas. Affected individuals may also have pitted acneiform scars in a perioral distribution. Other associations that are commonly seen include soft fibromas, follicular hyperkeratoses, and comedonal and cystic lesions in the flexural areas. Squamous cell carcinoma of the buttocks and perianal areas has been reported. The condition is thought to be secondary to mutations in KRT5 (keratin 5), POGLUT1 (protein O-glucosyltransferase 1), POFUT1 (protein O-fucosyltransferase 1), and PSENEN (presenilin enhancer protein 2). Mutations in KRT5 result in disruption of melanosome transfer. POGLUT1 and POFUT1 play an important role in the Notch signaling pathway involved in the regulation of keratinocyte and melanocyte proliferation and differentiation. Heterozygous mutations of PSENEN, which also affect the Notch signaling pathway, has been associated with hidradenitis suppurativa and a variant of DDD with lesions confined to the scrotum.

There is a slight female predominance, and all races are affected equally.