Feline plasmacytic pododermatitis is an uncommon condition affecting a cat’s paws, widely known as “pillow foot.” The disorder involves inflammation caused by the infiltration of plasma cells into the paw pads, leading to significant changes in their appearance and texture. This condition is not contagious and can affect cats of any age, sex, or breed.
Identifying the Symptoms
The most prominent sign of plasmacytic pododermatitis is a soft, puffy swelling of the paw pads, which gives them a “squishy” or pillow-like feel. This swelling primarily affects the large, central metacarpal and metatarsal pads, though the smaller digital toe pads can also be involved. The affected pads often change color, taking on a distinct purplish or deep violet hue.
Upon closer inspection, the surface of the pads may lose its normal texture, appearing scaly with fine, silvery-white lines. In more advanced instances, the swollen pads can become fragile and develop deep cracks or ulcerations. These open sores can lead to bleeding and a risk for secondary bacterial infections.
While the initial swelling may be painless, developing ulcers often causes discomfort and can lead to lameness. An owner might notice their cat limping, holding up the affected paw, or excessively licking the sore pads. The condition characteristically affects multiple paws at once rather than a single foot.
Causes and Diagnostic Confirmation
The precise trigger for plasmacytic pododermatitis is unknown, but it is considered an immune-mediated disease. The underlying mechanism involves an immune system malfunction that directs a massive number of plasma cells to infiltrate the paw pads. These cells produce antibodies that cause significant inflammation and swelling.
A notable association exists between plasmacytic pododermatitis and Feline Immunodeficiency Virus (FIV), as a significant percentage of affected cats also test positive. However, this is a correlation, not a direct cause. Many cats with pododermatitis are FIV-negative, and a pillow foot diagnosis does not automatically confirm an FIV infection.
A veterinarian begins the diagnostic process with a physical examination, noting the swelling and discoloration. To confirm the diagnosis, a fine-needle aspiration may be performed. This procedure uses a small needle to collect cells from the pad for analysis, which can reveal a high concentration of plasma cells.
The definitive method for diagnosis is a tissue biopsy for histopathology. A small piece of the affected pad is surgically removed and examined to confirm the plasmacytic infiltration. As part of the workup, veterinarians will recommend blood tests to screen for FIV and Feline Leukemia Virus (FeLV).
Available Treatment Paths
The primary treatment for plasmacytic pododermatitis is medical management aimed at modulating the immune system’s overactive response. The most common first-line medication is doxycycline. While an antibiotic, its effectiveness in this context is attributed to its anti-inflammatory and immunomodulatory properties, which help reduce plasma cell infiltration.
For cats whose symptoms do not resolve with doxycycline or in more severe cases, other medications may be required. Veterinarians may prescribe corticosteroids, such as prednisolone, to suppress the immune system and reduce inflammation. In resistant cases, more potent immunosuppressive drugs like cyclosporine might be used.
Surgical intervention is reserved for the most severe presentations of the disease. When paw pads are severely ulcerated, non-responsive to medication, or have developed painful lesions, surgical excision of the affected tissue may be necessary. This approach is considered when medical management fails to provide relief.
Recovery and Prognosis
The prognosis for cats with plasmacytic pododermatitis is favorable, with a majority of felines responding well to medical treatment. Many cats experience a significant reduction in swelling and discomfort once an appropriate therapeutic regimen is established, allowing the cat to resume normal activity.
The condition is known for its potential to recur, and inflammation can return even after successful treatment. In some instances, the condition resolves spontaneously without any intervention, though this is less common.
Long-term management involves monitoring the cat’s paws for any signs of returning puffiness or discoloration. Regular follow-up appointments with a veterinarian are important to catch any recurrence early and adjust treatment as needed.