Canine epidermolysis bullosa acquisita: a retrospective study of 20 cases.

Background: Epidermolysis bullosa acquisita (EBA) is a rare autoimmune subepidermal blistering disease of dogs and humans.

Objectives: Our objectives were to describe clinical phenotypes, histopathology and treatment outcomes of canine EBA.

Animals: Twenty dogs diagnosed with EBA based on a subepidermal blister formation and collagen VII autoreactivity.

Results: Most dogs were young (median: 1.2-year-old) with a male-to-female ratio of 2.3:1. Nine of 20 dogs (45%) developed lesions before one year of age and 11 of 20 dogs (55%) were great danes. Tense vesicles and bullae (18 of 20; 90%) and deep erosions and ulcers (20 of 20; 100%) were the most common lesions and these affected predominantly the oral cavity (19 of 20; 95%), pinnae (16 of 20; 80%), axillae (15 of 20; 75%) and footpads (14 of 20; 70%). Histopathology identified neutrophilic perivascular dermatitis (17 of 17; 100%) without or with (12 of 17; 71%) eosinophils, which occasionally equalled (four cases) or outnumbered neutrophils (two cases). Subepidermal vesicles were either devoid of inflammation or contained neutrophils with or without eosinophils, fibrin and/or haemorrhage. A complete remission of skin lesions was obtained in 14 dogs with a median time of 58 days. Glucocorticoids were used in these dogs either as a monotherapy (3 of 14; 21%) or in combination with other immunomodulating drugs (11 of 14; 79%). The median dose of prednisone was 3 mg/kg/day. The remaining six dogs were euthanized.

Conclusions And Clinical Importance: Canine EBA is a rare subepidermal blistering disease with an inflammatory phenotype and a predilection for young great danes and male dogs. The outcome of treatment appears more favourable than assumed previously.