Fatty Tissue Inflammation in Cats

The lumps caused by fatty tissue inflammation closely resemble tumors that may be benign or malignant. For this reason, any new bumps should be evaluated by a veterinarian. A biopsy may be recommended to confirm whether or not the lumps are cancerous. Fatty tissue inflammation is extremely painful for cats and may become life-threatening if left untreated. With early diagnosis and proper treatment, the prognosis for affected cats is very positive.

Inflammation of the fatty tissue, known medically as steatitis, pansteatitis, or yellow fat disease, is a rare condition that causes lumps under the surface of an affected cat’s skin. This is often the result of a combination of a diet high in unsaturated fatty acids and a deficiency of vitamin E or other antioxidants. Cats that eat excessive amounts of oily fish, especially red tuna, are most often impacted by the condition. Fatty tissue inflammation is less common now that most cats are fed commercial foods which are nutritionally balanced and often contain antioxidant supplements. 

Cats experiencing fatty tissue inflammation typically display one or more of the following symptoms:

• Fatty lumps under the skin
• Dull, greasy coat
• Flaky skin
• Loss of appetite
• Lethargy
• Fever
• Depression 
• Pain when touched
• Loss of agility
• Reluctance to move, jump, or play

Fatty tissue inflammation is more commonly found in young to middle-aged cats, and those that suffer from obesity. Male and female cats are equally likely to be affected. The primary cause of the condition is the feeding of an improper diet, mainly one that includes excessive amounts of red tuna, sardines, or white fish. Other possible causes include:

• Vitamin E deficiency
• Infection (viral, fungal, or bacterial)
• Inflammatory disorders
• Blood vessel diseases
• Cancer
• Radiation therapy
• Trauma 
• Immune-related diseases
• Pancreatic cancer

The condition can sometimes present with no known cause (idiopathic).

A thorough medical history will be needed, including details regarding the cat’s diet and the onset of symptoms. If owners have theories about other possible causes for the symptoms, this information should be shared with the veterinarian. 

A complete physical exam will be completed and the vet will likely order a series of standard lab tests including a complete blood count (CBC), blood chemistry panel, and urinalysis. Cats with fatty tissue inflammation may have an unusually high white blood cell count.

The vet will closely examine the lump and complete a fine-needle aspiration. The fluid drawn will be examined on a cellular level and cultured for the presence of fungus or bacteria. In some cases, a biopsy may be ordered. If the biopsied tissue is yellow-brown in color and has a firm texture it likely indicates that the lump is the result of a fatty tissue inflammation.

Treating fatty tissue inflammation in cats typically involves several levels of care.

Treatment of Acute Symptoms

Fatty tissue inflammation is extremely painful for cats. The first step in treatment often involves taking measures to control pain and improve quality of life. Corticosteroids are often prescribed to control pain and reduce inflammation and fever. Measures will be taken to encourage the cat to eat and, in some cases, a feeding tube may be needed to treat malnutrition. Any concurrent conditions that are present will need to be diagnosed and promptly treated.

Supplementation and Dietary Modification

Owners should immediately eliminate all fish from the cat’s diet and implement a feeding regimen that is based on a commercially available food that is balanced and nutritionally complete. Prescription-strength vitamin E supplements may be recommended.

Surgery

Surgical treatment is often needed to either drain or remove the lump. Following surgery, an Elizabethan collar will be used to keep the cat from irritating the affected area by pawing at it or licking. Antibiotics will often be prescribed to avoid post-surgical infection.

As long as the condition was treated promptly and dietary restrictions are followed closely, a full recovery is likely. It may take several weeks or months for the condition to fully resolve. During the healing period, the cat may continue to feel pain and is likely to show a reluctance to be touched. Owners should be aware of this and make efforts to physically handle the cat as little as possible.

Recovering cats should not be fed fish at all until the condition has fully resolved. After recovery, it should be given only on a rare special occasion. It is possible for cats to become addicted to the flavor of tuna and other fish, and they may begin to reject other types of food. Taking steps to ensure that this doesn’t happen is a key to preventing a recurrence of the condition.