The antibodies cause a separation of the epidermal cells and the release of chemicals (vasoactive amines) which increase the leakage of fluid from blood vessels resulting in swelling, blister formation and ulceration. Drugs reactions (including worming preparations) may be a trigger for some cases of pemphigus.

There are several forms of pemphigus which are distinguished by their distribution appearance.

Pemphigus foliaceous occurs in both dogs and cats most commonly between the ages of two and seven. The disease usually begins on the face and ears followed by the feet and groin. Spread can take weeks to months. Lesions are characterized by scaling and crusting with hair loss. Crusting can be very thick and develop to ulcers especially in cases which also have irritation leading to self trauma (less than 50%).

Pemphigus erythematosus is generally a less severe form of pemphigus which is mostly confined to the face. It is indistinguishable from early cases of p. foliaceous with erythema (redness), oozing, scaling and crusting.

Pemphigus vulgaris effects mainly the mucosa (lining of mouth), mucocutaneous junction (border of skin and mucosa) and nail beds. This is mainly a condition of dogs with ulcers being the predominant lesion. Secondary paronychia (infection of the nail bed) can lead to shedding of the nail. A small number of animals may have systemic (generalized) illness.

Skin biopsies are used to diagnose pemphigus. This via histopathology (microscopic examination) and immunofluorescence (using stains which identify antibodies).

Treatment of pemphigus is based on immunosuppressive drugs. Corticosteroids are usually the first line drugs used e.g. Prednisolone 2mg/kg twice daily. Reports suggest around 40% of animals will respond to Prednisolone alone. The dose can be tapered in these animals to the lowest effective dose for maintenance of a symptom free status. Non responsive cases are treated with additional chemotherapeutic drugs including Azathioprine (2mgkg daily) ,Chlorambucil (0.2mg/kg daily). Long term maintenance regimes using low doses of these drugs may be necessary to keep symptoms under control.