Acquired Dermal Macular Hyperpigmentation Mimicking Dowling Degos Disease: A Case Report

Acquired dermal macular hyperpigmentation (ADMH) is a recently coined term to encompass lichen planus pigmentosus (LPP), erythema dyschromicum perstans (EDP), and Riehl's melanosis. Here we report a 60 year- old female, with an insignificant past medical history, who presented to the dermatology clinic, with slightly itchy skin lesions on her body. The lesions were slowly increasing in number over the last 10 years. The patient was otherwise healthy and was not taking any medications. A review of systems was unremarkable. There was no similar case in the family and the parents did not show consanguinity. Skin examination revealed multiple well-defined non-scaly brownish macules scattered on her body. In addition, bilateral macules and papules were present in the inframammary folds. There were no skin lesions in the axillae, groin, and intergluteal folds. Differential diagnoses include Dowling Degos Disease (DDD), LPP, and EDP. A 4 mm punch skin biopsy was taken from skin lesions under the breast. It revealed hyperkeratosis, hypergranulosis, and acanthosis. The dermis showed a band-like infiltrate of mononuclear histiocytic cellular infiltrate with basal layer degeneration. According to the above clinicopathological findings, the diagnosis of lichen planus was made. The patient was reassured. She was started on hydroxychlorquine 200 mg tab bid, a topical steroid, and topical calcineurin inhibitors, and was asked to follow up regularly in the dermatology clinic.