What is erythema nodosum?
What causes erythema nodosum?
Common causes include:
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Infections, including streptococcal infections
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Sarcoidosis (a disease that causes small clumps of immune cells to grow in many of your organs)
Less common causes:
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Certain medicines, including antibiotics and birth control pills
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Pregnancy
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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
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Certain cancers
What are the symptoms of erythema nodosum?
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:
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Chest x-ray
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Blood tests
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Skin test for tuberculosis
