Abstract
The patient, a 64-year-old male with a history of delusional disorder, first experienced symptoms of suspicion toward his spouse at age 34. He was treated with psychotropic drugs for two years, leading to complete symptom remission and discontinuation of medication. After years of stability, delusions resurfaced two years ago. Amisulpride was ineffective, and risperidone was started but led to itching and plaques on his thighs, which evolved into fluid-filled and hemorrhagic lesions. Diagnosed with bullous pemphigoid (BP) via skin biopsy, he received corticosteroids, dapsone, and antibiotics. Risperidone was discontinued, but delusions reappeared, prompting its reintroduction. New bullous lesions emerged, suggesting risperidone's role in triggering them. Risperidone was replaced with aripiprazole, and melatonin improved sleep. The patient responded well, with both delusional symptoms and skin condition well-managed. This case highlights the need to consider drug-induced BP in elderly patients on antipsychotic medications.