Mucous membrane pemphigoid in dogs: a retrospective study of 16 new cases.

Background - Mucous membrane pemphigoid (MMP) is a chronic autoimmune subepidermal blistering disease of dogs, cats and humans. Objectives - The goal of this study was to describe the clinical, histological and immunological features and treatment outcomes of canine MMP. Animals - Sixteen dogs were diagnosed with MMP based on the presence of mucosal- or mucocutaneous-predominant vesiculation and/or ulceration, histological confirmation of subepidermal clefting and an age of disease onset greater than 6 months. Results - Six of 16 dogs (38%) were German shepherd dogs and their crosses. The median age of disease onset was 6 years (range: 1-10 years). At the time of presentation, the dogs exhibited erosions and ulcers in the oral cavity (11 of 16; 69%), nasal (nine of 16; 56%), periocular (eight of 16; 50%) and genital (six of 16; 38%) regions. Haired skin lesions were less frequent (six of 16; 38%) and involved mostly concave pinnae. Information on treatment outcome was available for 11 dogs (69%). A complete remission (CR) of lesions was achieved in 10 of 11 dogs (91%). The median time to CR was 33 weeks (range: 6-64 weeks). Treatment regimens varied widely but six of 10 (60%) dogs received a combination of tetracycline antibiotic and niacinamide alone, or with another drug, at the time of CR. Forty percent of the dogs in which CR had occurred experienced lesion relapse upon drug dose reduction. Conclusions and clinical importance - Canine MMP is a chronic and relapsing disease requiring long term treatment. Combination therapy is often needed to achieve CR.