Dowling-Degos disease (reticulate pigmented anomaly of the flexures): A clinical and histopathologic study of 6 cases

Background: Few case series describing Dowling-Degos disease (DDD) have been reported. Objective: Our purpose was to review the clinical and histopathologic findings in DDD. Methods: We reviewed the clinical and histopathologic findings in 6 patients with DDD who were evaluated at the Mayo Clinic. Results: In addition to the typical flexural pigmented reticulate macules, comedo-like lesions on the back or neck or both were present in all 6 patients; 3 patients had pitted peri oral scars, and 3 patients reported pruritus of affected flexural areas. Five patients were female, 5 patients had onset of pigmentation before age 24 years, and 3 patients had a family history of DDD. One patient had additional pigmentation involving the dorsum of the hands and proximal nailfolds and fingernail dystrophy. Histopathologically, pigmented rete ridge elongation with thinning of suprapapillary epithelium, dermal melanosis, and perivascular lymphohistiocytic infiltration were consistently observed. Conclusion: Comedo-like lesions, pruritus, and pitted perioral scars are common features in association with the reticulate flexural pigmentation. Histopathologically, pigmented rete ridge elongation and dermal melanosis of biopsy specimens from flexural areas are seen.