How I Treat- Feline Pemphigus Foliaceus

Pemphigus foliaceus is an uncommon, but not rare, autoimmune skin condition in cats. It is the most common autoimmune skin disease seen in cats, and the majority of cats that develop the disease are middle aged although a wide age span is reported (1). Pemphigus foliaceus is clinically characterized as a pustular, crusting disease and erosive lesions, often associated with alopecia developing in affected areas. Pustules are transient and fragile in the skin and crusting is therefore predominantly seen. Pemphigus foliaceus lesions are localized in around 20% of cases, whilst a more generalised distribution is seen in most cases (1). Lesions are almost always symmetrically distributed. Most commonly lesions are seen involving the pinnae, with crusting seen in Henry’s pockets, around the face, claw beds and nipples. Affected cats can be generally unwell and febrile. Typically the disease shows flares with a rapid development of clinical lesions, that then gradually are seen to resolve until the next flare develops. Pruritus is reported in around 3/4 of cases (1). Diagnosis is based on suggestive cytology showing neutrophils, occasional eosinophils and acantholytic keratinocytes and confirmed by skin biopsies showing subcorneal pustules containing acantholytic keratinocytes and neutrophils. Layered crust formation is typical for the disease as a secondary lesion. Other diseases able to cause acantholysis, such as dermatophytosis, should be ruled out. Clinical lesions are not uncommonly mistaken as a hypersensitivity disease due to the somewhat similar appearance. Careful assessment of macroscopically symmetrical skin lesions of crusting and pustules in cats, particularly in cases showing lesions affecting the pinnae, face and paws, should therefore be done to reduce the risk of mis-diagnosis. [...]