Erythema Nodosum

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

Common causes include:

• Infections, including streptococcal infections

• Sarcoidosis (a disease that causes small clumps of immune cells to grow in many of your organs)

• Inflammatory bowel disease

Less common causes:

• Certain medicines, including antibiotics and birth control pills

• Pregnancy

• Tuberculosis

• 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

Symptoms include:

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

• Fever

• Joint pain

Erythema Nodosum

Image

Photo provided by Thomas Habif, MD.

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:

• Chest x-ray

• Blood tests

• Skin test for tuberculosis

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

• Sometimes, corticosteroids (medicines to lower swelling)