P-51 Drug-Induced Erythema Multiforme or Drug-Induced Pemphigus Foliaceus: A Case Report

A 5-month-old female Brittany spaniel developed peracute crusting dermatitis after being treated with cephalexin for cystitis. The dog exhibited systemic symptoms such as hyperthermia, anorexia, and dehydration, along with painful dermatological signs including crusted and exudative lesions. Histopathological examination revealed features consistent with erythema multiforme, potentially linked to cephalexin. Despite symptomatic treatment, the condition progressed to a pustular dermatitis indicative of pemphigus foliaceus. Treatment with prednisolone, antiseptic baths, and antibiotics led to clinical improvement, and the lesions resolved completely without relapse for 4 years. This case highlighted the progression from erythema multiforme to pemphigus foliaceus as a drug-induced reaction.