Panniculitis

What is panniculitis?

Panniculitis is usually visible as a lump, but it is actually inflammation of the subcutaneous fatty tissue. Panniculitis is a common problem in cats, but is less so in dogs.

What causes panniculitis?

In younger animals with a single lump, the cause is often blunt trauma. In cats, panniculitis is often caused by bite wounds from fighting.

Other, much less common causes include:

• infections
• immunological reactions
• steroid treatment
• diseases of internal organs such as the pancreas or liver
• poor nutrition
• diseases that affect blood supply

These causes are usually only considered when there are multiple lumps, recurrences of panniculitis, or other signs of disease.

What are the clinical signs of panniculitis?

The most obvious sign of panniculitis is a lump. This lump may ulcerate, bleed, and become secondarily infected or put physical pressure on the surrounding tissue structures.

As the fat tissue degenerates, toxic substances may enter the blood stream causing your pet to have a fever or become depressed.

Classic sites for these lumps to develop are on the flanks (the side of the body between the ribs and the hip) of dogs and the abdomen of cats.

How is panniculitis diagnosed?

Although your veterinarian may suspect panniculitis with a history of the rapid appearance of one or more lumps and their location, an accurate diagnosis relies on the microscopic examination of tissue.

Fine needle aspiration (FNA), biopsy, or surgical excision of the entire lump may be performed. FNA involves taking a small needle with a syringe and suctioning a sample of cells directly from the lump and placing them on a microscope slide. A veterinary pathologist then examines the slide under a microscope.

In some cases, results from FNA may not be entirely clear and a biopsy may be necessary. A biopsy is the surgical excision of one or more pieces of the lump. The pieces are then examined by a veterinary pathologist under the microscope. This is called histopathology. If the entire lump is removed and submitted for examination, the pathologist can not only provide the most accurate diagnosis, but also assess whether the removal is complete. Histopathology can rule out other diseases, including cancer. Some forms of cancer resemble panniculitis. Because these cancers can be aggressive, early removal and examination of all lumps is important both for an accurate diagnosis and the development of a timely treatment plan.

What are the treatments for panniculitis?

  If secondary infection is present, antibiotic therapy may be needed as well. The goal is to find, treat, and/or remove any underlying cause or trigger of the panniculitis. Some cases of panniculitis are caused by bacteria or fungi and treatment of this underlying (primary) infection is necessary.

While the inflammatory response of the body may remove damaged tissue, permanent damage to the area (with scarring and loss of blood supply) may occur. This causes further problems unless the area is surgically removed.

Is there any special care that I should provide to my pet?

It is important to prevent your pet from rubbing, scratching, licking, or biting the lump(s), all of which can cause even further inflammation, itching, infection, ulceration, and bleeding. Any ulcerated area needs to be kept clean.

How will I know if the panniculitis is permanently cured?

If the condition in your pet is due to one of the rare non-traumatic causes, there may be further lumps or recurrence at the same site within days to weeks. It may be necessary to conduct more tests to find the cause and assess how the underlying problem can be cured.