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:
Sarcoidosis Sarcoidosis Sarcoidosis is a disease in which small clumps of inflammatory cells form in one or more of your organs. The clumps of cells are called granulomas. They aren't cancerous. When you have sarcoidosis... read more (a disease that causes small clumps of immune cells to grow in many of your organs)
Less common causes:
Certain medicines, including antibiotics and birth control pills
Behçet disease Behçet Disease Behçet disease is chronic blood vessel inflammation (vasculitis) that can cause painful mouth and genital sores, skin lesions, and eye problems. The joints, nervous system, and digestive... read more —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
What are the symptoms of erythema nodosum?
Painful, red or purple bumps, usually on your shins
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:
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)