title: Suspected polymyxin B-induced pemphigus vulgaris in a dog.
abstract: A case of pemphigus vulgaris (PV), putatively induced by topical application of polymyxin B ear drops, is described. A 3-year-old, female Tosa Inu, presented with acute onset swelling, blistering and ulceration of the pinnae, nostrils, lips and oral mucous membranes. The dog was depressed, febrile and anorexic. For 7 days prior to the onset of the acute ulcerative disease, polymyxin B ear drops had been applied to both ears to treat an ear infection. Skin and mucosal biopsies showed suprabasilar cleft formation and acantholysis, indicative of PV. The polymyxin B ear drops were discontinued and the dog was treated with intravenous fluids, systemic and topical antibacterial therapy, and immunosuppressive therapy comprising prednisone and azathioprine. Complete remission was noted after 2 weeks, and the immunosuppressive therapy was discontinued one month later. No clinical signs of PV recurred over a 1 year follow-up period. As PV does not usually resolve spontaneously, or enter long-term remission, it was considered that the condition was most likely drug induced due to the aural application of polymyxin B.
authors.affiliation: Division of Companion Animal Studies, Department of Clinical Veterinary Science, University of Bristol, Langford House, Langford, Bristol BS40 5DU, UK. jan.rybnicek@bristol.ac.uk
authors.forename: Jan
authors.initials: J
authors.lastname: Rybnícek
authors.forename: Peter B
authors.initials: PB
authors.lastname: Hill
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000139:chemically induced* / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D004431:Ear, External; D005260:Female; D010392:Pemphigus / Q000139:chemically induced / Q000175:diagnosis / Q000662:veterinary*; D011112:Polymyxin B / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D000900:Anti-Bacterial Agents; D011112:Polymyxin B