Pemphigus Foliaceus
Pemphigus foliaceus (PF) is a rare auto-immune skin disease affecting approximately 5 cats per 1000 per 10 years. To put pemphigus into perspective, Dr. Liz has seen 2 cases on 6 years of cat-only practice.
Auto-immune diseases are diseases in which the body’s immune system starts to attack its own cells and tissues. In PF, auto-antibodies target the adhesive cells of the skin known as desmosomes. As the desmosomes get attacked, the skin becomes fragile and breaks away.
Auto-immune diseases are diseases in which the body’s immune system starts to attack its own cells and tissues. In PF, auto-antibodies target the adhesive cells of the skin known as desmosomes. As the desmosomes get attacked, the skin becomes fragile and breaks away.
What causes it?
The cause of PF is an inappropriate immune response. What triggers this inappropriate response is often times unknown. In theory, anything that triggers the immune system such as infection, vaccination, medication, etc. could cause the body to start making auto-antibodies.
What does it look like?
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The main feature of PF is pus-filled crusty lesions around the ears, eyes, nose, and feet of a cat. There is no breed predisposition as most cases of PF are found in domestic short hair cats. This photo shows the classic pus-filled ear lesions in an affected cat.
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How is it diagnosed?
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For veterinarians who have seen PF before, the lesions are very classic and suspicions may be raised on initial examination.
The only way to diagnose PF is to take a tissue sample (also known as a skin biopsy) and have the cells examined under the microscope is a process called histopathology. Pathologists are looking for the classic cell changes associated with PF known as acantholytic cells. The two diseases that can mimic PF are:
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How is it treated?
As this disease is driven by the immune system, the cornerstone of treatment is immunosuppressive drug therapy. The most common immunosuppressive drugs used in cats are steroidal anti-inflammatories including dexamethasone, prednisolone, and triamcinolone. In some cases, newer immunosuppressive drugs such as cyclosporine can be used.
What is the prognosis for a cat with PF?
Presuming that the disease responds well to immunosuppressive therapy, the prognosis or outcome of PF in a patient is good. The biggest concern is that sometimes high doses of steroids are required to cause skin lesions to resolve. Cats on high doses of steroids over a long period of time can develop diabetes.
