Dapsone-Induced Photosensitivity: A Rare and Overlooked Clinical Dilemma.

INTRODUCTION: Dapsone (4,4'- diamino diphenyl sulfone, DDS) is an antimicrobial sulfonamide used for non-dermatological and dermatological disorders. Dapsone has been associated with a wide range of cutaneous adverse effects, with photosensitivity being an unusual side effect. CASE PRESENTATION: A case of dapsone-induced photosensitivity was reported in a patient with lepromatous leprosy. A 46-year-old male patient complained of redness and scaling, with itching over his face, nape, the flexural aspect of his neck, and bilateral upper and lower limbs, during the second month of multidrug multibacillary therapy. Examining the face, neck, and upper and lower limbs revealed erythematous scaly plaques with crusting and fissuring. Dapsone-induced photosensitivity was suspected, and the drug was stopped immediately. The patient was started on 0.5 mg/kg of prednisolone, antihistamines, and sunscreen. After improving symptomatically, the patient was discharged from the hospital and started on multidrug multibacillary therapy without dapsone. CONCLUSION: Although it is uncommon, dapsone-induced photosensitivity should be taken into account when patients exhibit photodermatoses while receiving treatment. Morbidity and unnecessary regimen discontinuation can be avoided with early detection followed by prompt care. This case emphasizes how crucial it is for physicians to be aware of this unusual side effect.