Panniculitis

ByJulia Benedetti, MD, Harvard Medical School
Reviewed/Revised May 2024
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Panniculitis is inflammation of the fat layer beneath the skin.

  • Panniculitis can develop in people with certain infections, injuries, and autoimmune disorders.

  • Typical symptoms include tender, red or purple bumps under the skin.

  • The diagnosis is based on the person's symptoms and often a biopsy.

  • There is no specific treatment, but doctors may give medications to relieve symptoms.

(See also Overview of Hypersensitivity and Reactive Skin Disorders.)

The cause of panniculitis is not known, but it can develop in people with infections, exposure to cold temperature, injury, systemic lupus erythematosus, disorders of the pancreas, inflammatory disorders (such as inflammatory bowel disease and polyarteritis nodosa), and alpha-1 antitrypsin deficiency. Erythema nodosum is a type of panniculitis.

Symptoms of Panniculitis

Panniculitis is characterized by tender, red or purple bumps (nodules) that originate deep in the layer of fat beneath the skin (the subcutaneous layer). They tend to be large, measuring several centimeters in diameter.

The bumps are most common on the legs and arms and occur less often on the buttocks, trunk, and face.

Panniculitis
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This photo shows red bumps (nodules) beneath the skin on the thighs of a person who has panniculitis.
© Springer Science+Business Media

People may have symptoms of general bodywide inflammation such as fever, joint and muscle pain, and feeling ill.

Diagnosis of Panniculitis

  • A doctor's evaluation

  • Often skin biopsy

Doctors base the diagnosis on the results of a physical examination.

The diagnosis of panniculitis is sometimes confirmed when doctors remove a bump or a small piece of one and then analyze it with a microscope (biopsy).

Treatment of Panniculitis

  • Anti-inflammatory medications

  • Immunosuppressants

There is no specific treatment for panniculitis.

Corticosteroids and other medications that suppress the immune system (immunosuppressants) or chemotherapy may be given to people whose symptoms are getting worse.

Any causes are also treated.

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