Pillow Foot in Cats: Our Vet Shares What to Do

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  • What is plasma cell pododermatitis (Pillow Foot) in Cats?

    Also known as pillow foot, feline plasma cell pododermatitis (FPP) is a rare autoimmune disorder in cats characterized by inflammation of the paw due to infiltration of plasma cells (a type of white blood cell known as a plasmacyte that secretes antibodies in response to infection).

    One pathologist searched the database of an unnamed diagnostic laboratory which found a higher incidence in male cats, with a median age of 6 years and an age range of 9 months to 17 years.

    Causes

    The etiology of plasma cell pododermatitis is unknown but it is thought immune hyperactivity is the root cause. One study found more than 50% of affected cats were positive for feline immunodeficiency virus or feline leukemia virus. Other possible triggers include food hypersensitivity, glomerulonephritis, and plasmacytic stomatitis.

    Clinical signs

    Symptoms can vary from cat to cat depending on the severity of the condition. Lesions may be confined to a single pad but typically affects multiple pads. Any footpad can be affected, but FPP is seen most often on the large metacarpal pads on the front legs or the metatarsal pads on the hind legs.

    • Purple, spongy swelling on one or more of the paw pads followed by hyperkeratosis and ulceration which may bleed
    • Secondary bacterial infection of the ulcerated lesion
    • Lameness
    • Erythema (redness) or purple cast closely resembling bruising
    • Splitting of the footpad
    • Excessive paw licking

    When to be worried / When to see the vet

    Veterinary care should be sought for any cat exhibiting signs of pain or lameness. If left untreated, this condition can make ambulation very uncomfortable for cats. Paw pads can become ulcerated and infected which can spread infection up the limb. Pain associated with this condition may cause cats to have a decreased appetite and lose weight. If you are at all concerned about your cat’s comfort you should seek veterinary advice as soon as possible. 

    Diagnosis

    The veterinarian will perform a physical examination and obtain a medical history from you including underlying health issues and when did clinical signs first develop. A tentative diagnosis may be made based on the gross appearance of FPP lesions. However, a diagnostic workup will be necessary to evaluate the overall health of the cat and rule out other possible causes such as tumors, eosinophilic granuloma complex, pemphigus, vasculitis, and acetaminophen toxicosis.

    Baseline tests: Biochemical profile, complete blood count, and urinalysis can provide information on the overall health of the cat as well as check for underlying infections. A complete blood count may reveal elevated lymphocytes and hypergammaglobulinemia.

    FIV test: This blood test looks for antibodies to the feline immunodeficiency virus.

    Biopsy and histopathology: A diagnosis is made by obtaining a biopsy from the affected pad and histopathology, which is the microscopic examination of the sample. This will reveal infiltration of plasma cells along with a smaller number of macrophages and lymphocytes.

    Treatment

    The goal of treatment is to address the underlying cause if one can be established as well as address the pododermatitis. Some cats with mild plasma cell pododermatitis may spontaneously recover.

    There are several treatment options available which can vary depending on the severity of the condition.

    Antibiotics: Doxycycline is an antibiotic with immunomodulating effects which help to suppress the immune system. 50% of cats showed a good response after two months of therapy. Cats will remain on doxycycline for several months before treatment is discontinued. Doxycycline has the potential to cause inflammation of the esophagus (esophagitis), therefore it is recommended that a pill pocket or gel capsule be used to administer the drug followed by some water to wash it down. 

    Immunosuppressive therapy: Cats who don’t respond to doxycycline can benefit from oral steroids such as prednisolone or cyclosporine to suppress the immune system.

    Methylprednisolone acetate (Depo-Medrol) is a slow-release, long-acting injectable drug which avoids the need to medicate the cat daily, however, there are potential side effects with this medication and it is contraindicated in cats with diabetes, chronic kidney disease, congestive heart failure, and Cushing’s syndrome. Dexamethasone is a shorter-acting steroid that may be administered via injection. 

    Surgery: Large and ulcerated masses on the foot which don’t respond to medical therapies may require surgical excision.

    Home remedies for pillow foot in cats

    Given this condition is caused by immune-mediated disease, many remedies will not cure the underlying problem. Probiotics have been implicated in helping animals recover from auto-immune diseases. These can be used alongside omega-3 fatty acids to help reduce inflammation. Some owners have tried Epsom salt soaks to help reduce inflammation in the feet. This soak cannot be consumed or else it may cause gastrointestinal upset. 

    Recovery from pododermatitis in cats

    Cats may take several days to weeks to begin to recover. You should see that the ulceration of the pads will start to regress alongside the swelling. Cats will become much more comfortable and willing to walk on affected feet. Treatment is continued until complete resolution has been seen which usually takes around 10 weeks. Some cats may go into remission while others may need lifelong treatment. 

    Prognosis

    The prognosis for cats with plasma cell pododermatitis is good. Cats who have achieved remission may be weaned off medication after several months. Some cats will require lifelong therapy.

    Questions to ask your veterinarian

    It is important to work closely with your veterinarian to ensure you are taking the appropriate actions to make sure your cat is recovering from this condition. 

    Some important questions to ask are:

    • Is my cat painful?
    • Should pain medication be part of the treatment regimen?
    • How can I stop my cat from licking his/her paw? 
    • Is there a topical treatment I can use?
    • What litter is best for ulcerated paws?
    • When should we see improvement? 
    • How long will my cat need to continue this medication? 
    • Should I take my cat to see a dermatologist?
    • Is surgery indicated for my cat? 

    Frequently asked questions

    Is pillow foot in cats painful?

    • Depending on the severity of the disease it is likely to be painful. Cats with swollen or ulcerated paws are often in pain. A sign of pain is lameness or unwillingness to walk. 

    How to tell if your cat’s paws are swollen

    • The easiest way is to compare the affected paw to one that appears more normal. You can take a photo of each and compare them directly. You can also search for images of normal paw pad anatomy in cats.

    How common is pillow foot in cats?

    • This disease is quite rare in cats. 

    Is plasma cell pododermatitis contagious?

    • No. This is an immune-mediated disease and is not directly contagious. Cats with this disease may be FIV positive. FIV is very contagious to other cats.

    Will pododermatitis go away on its own?

    • Given this is an immune-mediated disease, it is unlikely to resolve without treatment. Some cats with very mild disease may have spontaneous improvement. 

    Do you recommend a specific type of litter for cats with pillow foot?

    • It is best to avoid claw litter which can get stuck to ulcerated paw pads. I generally like paper-based litter for cats with diseases of the paws. 

    Author

    • Dr Paula Simons, Veterinarian

      Dr Paula Simons graduated from the Ontario Veterinary College with a Doctorate in Veterinary Medicine (DVM) in 2019. She is currently working at 'Cornell University Veterinary Specialists' (CUVS) in Connecticut as an Emergency and Critical Care veterinarian resident (see her work profile). CUVS is a 24/7 Emergency and Critical Care Facility certified by the Veterinary Emergency & Critical Care Society, indicating the highest level of patient care.