Merck Manual

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Julia Benedetti

, MD, Harvard Medical School

Last full review/revision Jul 2020| Content last modified Jul 2020
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Topic Resources

Panniculitis describes inflammation of the subcutaneous fat that can result from multiple causes. Diagnosis is by clinical evaluation and biopsy. Treatment depends on the cause.

(See also Erythema Nodosum.)

Panniculitis can be classified as lobular or septal depending on the principal site of the inflammation within the fat.

Etiology of Panniculitis

There are multiple causes of panniculitis, including

Symptoms and Signs of Panniculitis

Panniculitis is characterized by tender and erythematous subcutaneous nodules located over the extremities and sometimes over the posterior thorax, abdominal area, breasts, face, or buttocks. Rarely, nodules can involve the mesentery, lungs, scrotum, and cranium. Signs of systemic inflammation can accompany panniculitis.

Diagnosis of Panniculitis

  • Clinical evaluation

  • Excisional or incisional biopsy

Diagnosis of panniculitis is by usually by clinical appearance and can be confirmed by biopsy.

Treatment of Panniculitis

  • Supportive care

  • Anti-inflammatory drugs

  • Immunosuppressants

Any underlying causes of panniculitis are treated. There is no specific definitive treatment for panniculitis. Several strategies have been used with modest results, including nonsteroidal anti-inflammatory drugs, antimalarials, dapsone, and thalidomide.

Corticosteroids (1 to 2 mg/kg orally or IV once a day) and other immunosuppressive or chemotherapeutic drugs have been used to treat patients with progressive symptoms or signs of systemic involvement.

Key Points

  • Causes of panniculitis can vary widely.

  • Diagnose panniculitis by clinical evaluation (including presence of tender, red, subcutaneous nodules) and confirm with excisional or incisional biopsy.

  • Treat panniculitis supportively and consider anti-inflammatory or immunosuppressive drug therapy, particularly if manifestations are severe.

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