Suspected multiple autoimmune syndrome involving pemphigus foliaceus in two unrelated dogs

A 6‐year‐3‐month‐old, neutered, female miniature schnauzer, and a 9‐year‐old, neutered, female cocker spaniel presented with dermatological findings consistent with pemphigus foliaceus. Both dogs were diagnosed with another primary immune‐mediated disorder on presentation; suspected/presumptive immune‐mediated haemolytic anaemia in Case 1, and suspected/presumptive immune‐mediated haemolytic anaemia and suspected immune‐mediated thrombocytopenia in Case 2. These conditions were successfully managed with immunosuppressive therapy, but the dogs developed further autoimmune disorders during follow‐up; keratoconjunctivitis sicca and diabetes mellitus in Case 1, and immune‐mediated polyarthritis and keratoconjunctivitis sicca in Case 2. Additionally, Case 2 was diagnosed with large cell lymphoma at the end of the disease course, notable in the context of a suggested connection between autoimmunity and subsequent immune‐system neoplasia in this species. This report describes two cases diagnosed with pemphigus foliaceus that both developed several additional autoimmune diseases during follow‐up, consistent with the definition of multiple autoimmune syndrome.