THE PET HEALTH LIBRARY By Wendy C. Brooks, DVM, DipABVP Educational Director, VeterinaryPartner.com

Plasma cell pododermatitis is a foot pad disease of cats that is fairly classical in its appearance, yet its significance is poorly understood as many affected cats do not require therapy. Plasma cell pododermatitis literally means foot inflammation involving infiltration by plasma cells. Plasma cells are activated lymphocytes in full anti-body producing maturity. The fact that this cell of the active immune system is involved in this condition implies some sort of immune stimulation in the genesis of the disease. Understanding of plasma cell pododermatitis has not progressed far enough to begin to suggest what sort of stimulation this might be. Some studies have found a link between plasma cell pododermatitis and feline immunodeficiency virus (FIV) infection so it is important to screen an affected cat for this virus. Exactly what the link is between these two conditions remains unclear.

An affected foot pad develops a classic mushy appearance and balloons out as shown in the picture above. The skin of the pad may develop a purplish tint also shown above. All four feet may or may not be affected but rarely is only one foot affected. Any age, gender, or breed of cat can be affected. Most cats with this condition are not in pain and require no treatment, but if lameness develops treatment with corticosteroid hormones is generally effective temporarily. If ulcers or sores develop on an affected foot pad, these often must be removed surgically.

Confirming the Diagnosis

If the physical appearance of the foot is not obvious, a biopsy of the foot pad should confirm the presence of plasma cell pododermatitis. Other foot pad swellings such as tumors, insect bites, or proliferations from eosinophilic granuloma complexusually only affect a single foot. The blood tests of cats with plasma cell pododermatitis usually have elevated numbers of circulating lymphocytes and high circulating antibody levels.

Treatment

Suppression of this immune reaction is the core of therapy for cats in which therapy is deemed necessary. This involves injections of methylprednisolone acetate (Depo-Medrol) or high doses of oral prednisone. A response is generally clear in 2 to 3 weeks with peak improvement taking as long as 3 months. A newer therapy emerging for this condition is pentoxifylline. Doxycycline, an antibiotic with immuno-modulating properties, has also been used with some success.

Date Published: 8/30/2004 1:21:00 PM
Date Reviewed/Revised: 04/14/2008