Drug-Induced Pseudoporphyria: A Case Report

Pseudoporphyria is an uncommon dermatosis resembling porphyria cutanea tarda (PCT). The exclusion of true porphyria, especially PCT, is critically essential for diagnosing pseudoporphyria. It has an unknown underlying pathophysiology with a normal or near-normal porphyrin profile. Pseudoporphyria has been associated with chronic renal failure and hemodialysis, medications, and tanning beds. In drug-induced pseudoporphyria cases, eliminating the suspected photosensitizing drug improves the disease typically within weeks to months (on average eight weeks). In genetically predisposed individuals, phototoxic metabolites may trigger the development of skin fragility, bullae, milia, and scarring on the dorsum of the hands and other sun-exposed areas. Wearing a broad-spectrum sunscreen and maintaining strict ultraviolet protection is essential in cases of pseudoporphyria. We report the case of a 20-year-old male who presented to us with complaints of photosensitivity and multiple erosions with irregular scars over photo-exposed areas involving the dorsum of the hands and face predominantly. The patient was evaluated further to determine the underlying cause. A wood's lamp examination of the urine was done, which did not show fluorescence. Based on clinical and laboratory findings, the diagnosis of pseudoporphyria was made, and the patient was started on the oral antimalarial agent hydroxychloroquine sulfate with strict sun protection.