How to Diagnose Pillow Foot (Plasma Cell Pododermatitis) in Cats
Feline plasma cell pododermatitis, also referred to as
pillow foot, is a relatively rare skin disorder in cats marked by swelling and softening of the paw pads. This condition can cause discomfort, lameness, and occasionally more systemic symptoms. Accurate diagnosis is essential to manage this condition effectively.
Recognizing the Signs of Pillow Foot
Initial suspicion of pillow foot often begins with an owner noticing physical changes in their cat’s paw pads:
- Swollen, mushy paw pads that are unusually soft to the touch
- Discoloration to a deep pink or purple hue, sometimes streaked with white striations
- Formation of open sores or ulcers, which may bleed
- Limping, reluctance to walk, or general lethargy due to discomfort
These symptoms often affect multiple feet, especially the
metacarpal and metatarsal pads. In some cases, even digital pads show involvement.
Initial Veterinary Evaluation
When a veterinarian is presented with a suspected case of pillow foot, the clinical appearance is usually the first diagnostic indicator. The typical swollen, soft, and discolored paw pads can strongly suggest this condition.
Diagnostic Tests for Confirmation
To confirm the presence of feline plasma cell pododermatitis, specific tests are employed:
- Fine-Needle Aspiration (FNA) Cytology: A small needle is inserted into the affected pad to obtain cell samples, which are evaluated for plasma cell presence.
- Biopsy: If FNA is inconclusive, a tissue sample can be surgically removed and analyzed histologically to confirm plasma cell infiltration.
- Blood Tests: Cats with pillow foot often show elevated globulin levels and changes in white blood cell counts, particularly lymphocytes.
- Virus Screening: Testing for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) is recommended, as a strong correlation exists. FIV positivity occurs in 44%–63% of affected cats.
Differential Diagnoses
It is important to distinguish pillow foot from other potential causes of paw swelling:
- Bacterial or fungal infections – typically target one foot; often present with signs of infection
- Eosinophilic granuloma complex – inflammation with different histologic features
- Tumors – require further imaging or biopsy
- Insect bites or trauma – notable for sudden onset and localized swelling
Correct diagnosis is crucial as treatment approaches vary significantly.
Additional Signs to Watch For
Though paw pad changes are the primary hallmark, some cats exhibit systemic or seemingly unrelated symptoms:
- Swelling at the bridge of the nose
- Stomatitis – inflammation of the mouth and gums
- Upper respiratory signs
- Lymphadenomegaly – enlarged lymph nodes
- General symptoms like fever, lethargy, or poor appetite
These may indicate a more systemic immune dysfunction or concurrent illness and should be evaluated.
Prognosis and Follow-Up
The outlook for cats with pillow foot is generally positive with appropriate treatment. The most effective therapy usually starts with
doxycycline, which has antibiotic and immune-modulating properties. If unresponsive, options include glucocorticoids or
cyclosporine.
In rare, severe cases with non-resolving ulceration, surgical removal of the affected tissue may be necessary. Regular veterinary follow-ups, even after symptoms resolve, are crucial to monitor for potential relapses or side effects of long-term medication.
Conclusion
Diagnosing
pillow foot in cats relies on careful observation, clinical examination, and confirmatory tests like cytology or biopsy. Indications of systemic illness, viral co-infections, or other skin conditions must also be ruled out. With timely intervention and appropriate therapy, most cats experience good outcomes, though some may need ongoing care.
Owners who suspect this condition should seek immediate veterinary attention. Early action can greatly improve comfort and long-term prognosis for affected felines.
