Erythema Dyschromicum Perstans in a Patient with Prolonged Omeprazole Exposure and Clinical Improvement During Dapsone Therapy: A Case Report

Abstract

Erythema dyschromicum perstans (EDP) is an uncommon acquired dermal macular hyperpigmentation disorder characterised by slowly progressive grey-to-blue macules and patches. Its aetiology remains uncertain, and treatment responses are variable. We report a 59-year-old woman with confluent blue-grey hyperpigmented macules involving the face and neck and a history of omeprazole 20 mg daily for approximately two years. Dermoscopy demonstrated a brown pigment network, and histopathological examination showed epidermal atrophy and hyperpigmentation, vacuolar alteration at the dermoepidermal interface, scattered necrotic keratinocytes, papillary dermal melanophages, and a superficial lymphohistiocytic infiltrate. The clinicopathological findings supported a diagnosis of EDP. Omeprazole exposure was considered a possible associated trigger because similar cases have been reported, but causality could not be established. Treatment with an intermittent dapsone-containing regimen together with vitamin D, melatonin, and photoprotection was followed by visible clinical improvement after three months. This case supports consideration of medication exposure in the evaluation of acquired dermal macular hyperpigmentation and illustrates the need for cautious interpretation of therapeutic response in a single uncontrolled case.