Pemphigus-like Drug Reaction after Surgical Removal of a Splenic Hemangiosarcoma in a Dog

A 7-year-old spayed female Shih-tzu dog with 4-month history of anorexia and weight loss was diagnosed with splenic hemangiosarcoma. One week after splenectomy, the dog developed severe, multifocal, coalescing erosive and ulcerative dermatosis with epidermal collarettes and crusts on the dorsal trunk. The dog was prescribed systemic antibiotics comprising cephradine and enrofloxacin postoperatively. Histopathological examination of skin biopsies from haired skin lesions revealed changes consistent with pemphigus foliaceus (PF). Tentative diagnosis for this patient was pemphigus-like drug reaction resulting from cephradine treatment. However, given the dog's history of hemangiosarcoma, paraneoplastic pemphigus (PNP), a rarely reported cancer-related pemphigus in dogs, was also considered for tentative diagnosis. Significant clinical remission of dermal lesions was achieved with four weeks of prednisolone and mycophenolate mofetil (MMF) treatment. Drugs were gradually tapered and eventually discontinued with concurrent reduction of dermal lesions, and no further recurrence was noted.