Panniculitis

ByJulia Benedetti, MD, Harvard Medical School
Reviewed/Revised May 2024
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Panniculitis is 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 to violaceous 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, such as fever and malaise, can accompany panniculitis.

Panniculitis
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This photo shows violaceous infiltrated plaques of the anterior-medial part of the thighs.
© Springer Science+Business Media
Sclerosing Panniculitis
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This photo shows painful inflammation of the subcutaneous fat in the lower extremity resulting from lipodermatosclerosis, which can be confused with cellulitis.
© Springer Science+Business Media

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 medications

  • Immunosuppressants

Corticosteroids (1 to 2 mg/kg orally or IV once a day) and other immunosuppressive or chemotherapeutic agents 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, erythematous, subcutaneous nodules) and confirm with excisional or incisional biopsy.

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

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