Drug eruption in a cat resembling pemphigus foliaceus

An 18-month-old Siamese cat, under treatment with cimetidine, developed an exfoliative dermatitis involving the ears, face and feet. Foot-pad lesions and paronychia with a caseous exudate were also present. Histopathology of skin biopsies showed subcorneal pustules involving the hair follicles. These findings were suggestive of pemphigus foliaceus. However, the presence of cutaneous vasculitis and the results of immunofluorescence testing did not support this diagnosis. Skin lesions disappeared when cimetidine treatment was stopped and reappeared with its re-use. A diagnosis of drug eruption was made.