Pemphigus foliaceus (PF)[i] is an auto-immune disorder in which the patient’s immune system attacks components of their own skin, specifically the structures that hold the skin cells together. It is a pustular disease but progression from red bumps called a papules to pustules to rupture of the pustules can happen quickly so that the pet parent sees crusts on the skin as the major clinical sign. The head, face, and ears are commonly affected areas. With time, crusts may also be noted on the body and legs, thickening of foot pads may become evident and inflammation of the nail beds may be a symptom in cats. Affected animals may or may not be itchy.
What causes the immune system to react in this manner?
In most cases we do not know what causes the disease. Some patients may be genetically prone such as the Chow Chow, Akita, Collie and Schipperke. Medications, allergies or serious illness may predispose a pet to developing PF.
How is the diagnosis made?
A biopsy of the skin is typically needed. The sample is then sent to a pathologist specializing in skin disease to confirm diagnosis.
What can be done if my pet has PF?
A combination of medications is typically needed to induce remission. We typically employ two immunosuppressive medications, one that works quickly, but needs to be tapered due to concern for long term side effects. The second medication, which typically is slower to take effect, is utilized so that with time we use less of each medication. These medications can have serious side effects and regular checkups with serial testing of lab work is crucial.
What is the long term prognosis?
Prognosis is good for management. We can induce remission and manage approximately 80-85% of patients with this disorder. This is an incurable disorder for which medications will be needed for life.
[i] Muller and Kirk’s Small Animal Dermatology, 7th edition. In chapter 9 on Autoimmune and Immune mediated Dermatoses. Page 440-445.