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Erythema Nodosum


The Manual's Editorial Staff

Last full review/revision Jan 2021| Content last modified Jan 2021
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What is erythema nodosum?

"Erythema" means red-colored. "Nodosum" means nodules (lumps or bumps).   

Erythema nodosum is an inflammatory reaction in the layer of fat under your skin. It causes red or purplish bumps under your skin, often on your shins.

  • Erythema nodosum is most common in people in their 20s and 30s, especially women

  • It's usually caused by a reaction to a medicine or an infection

  • In addition to the bumps on your skin, you may have fever and joint pain

  • It usually gets better on its own in 3 to 6 weeks

What causes erythema nodosum?

Common causes include:

Less common causes:

  • Certain medicines, including antibiotics and birth control pills

  • Pregnancy

  • Behçet disease—a long-term inflammation (swelling) of blood vessels that can cause painful mouth and genital sores, skin blisters, and sometimes problems with your eyes, joints, or organs

  • Certain cancers

What are the symptoms of erythema nodosum?

Symptoms include:

  • Painful, red or purple bumps, usually on your shins

  • Fever

  • Joint pain

How can doctors tell if I have erythema nodosum?

Doctors can usually tell you have erythema nodosum by looking at the bumps on your skin. Sometimes to know for sure they'll do a biopsy (take out a small piece of tissue to look at under a microscope).

To find out what's causing your erythema nodosum, they may do other tests, such as:

How do doctors treat erythema nodosum?

Erythema nodosum gets better on its own after 3 to 6 weeks. If your erythema nodosum is caused by an infection, doctors will treat the infection. The following may help you lessen pain:

  • Bed rest

  • Cool compresses

  • Keeping your leg elevated

  • Taking nonsteroidal anti-inflammatory drugs (NSAIDs—such as aspirin or ibuprofen)

  • Sometimes, your doctor may have you take potassium iodide to help with symptoms

  • Sometimes, corticosteroids (medicines to lower swelling)

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