Successful treatment of a mucous membrane pemphigoid in a young dog.

Mucous membrane pemphigoid was diagnosed in a 2.5-year-old male intact foxhound-beagle cross which was presented with an acute onset of non-pruritic, multifocal, slowly progressive erosive-ulcerative dermatitis predominantly affecting the nasal planum, eyelids and muzzle with multiple vesicles on the inner pinnae, oral mucosa and tongue. The diagnosis was based on clinical signs and histological examination of skin biopsies. The patient did not respond to immunosuppressive prednisolone therapy, but went into complete remission with oral doxycycline and niacinamide and stayed in remission on long-term exclusive niacinamide treatment.

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.

Laminin-5 is targeted by autoantibodies in feline mucous membrane (cicatricial) pemphigoid.

In human and canine patients with mucous membrane (cicatricial) pemphigoid (MMP), circulating autoantibodies have been shown to target multiple epidermal basement membrane antigenic epitopes. These autoantigens include collagen XVII in humans and dogs, as well as laminin-5, laminin-6 or integrin alpha-6/beta-4 in human beings. The purpose of this study was to determine if autoantibodies targeted laminin-5 in a cat exhibiting clinical and microscopic lesions resembling those of MMP in humans. In this patient, an indirect immunofluorescence (IF) assay revealed circulating IgG and IgA autoantibodies that bound to the basement membrane zone on the dermal side of salt-split gingiva (titer 1:1000 for IgG and 1:50 for IgA). Immunoblotting, performed with affinity-purified human laminin-5, demonstrated that the autoantibodies bound the alpha-3 chain of this heterotrimer. These observations identify laminin-5 as one of the antigens recognized by circulating autoantibodies in this feline homologue of MMP in humans and dogs.