Patient education: Erythema nodosum (The Basics)

What is erythema nodosum? — Erythema nodosum is a condition that causes painful red, red-brown, or purple bumps on the legs (picture 1). The bumps can look like bruises. Some people get erythema nodosum after an infection called "strep throat." It can also happen with other conditions, or by itself.

What are the symptoms of erythema nodosum? — The main symptom is painful red, red-brown, or purple bumps on the legs. These are usually on the shins. But some people also have bumps on the thighs, arms, or upper body.

Some people have other symptoms before or after the bumps. These can include:

●Pain in the joints

●Fever

●Feeling sick, like with the flu

Will I need tests? — Yes. Your doctor or nurse will do an exam and learn about your symptoms. Many different conditions can cause erythema nodosum or symptoms like it. Your doctor or nurse can order tests to check for these conditions. Tests can include:

●Blood tests

●Chest X-ray

●A test for strep throat – Your doctor or nurse can run a swab (Q-tip) along the back of your throat and test the swab for bacteria.

●A skin test or blood test to check for tuberculosis – Tuberculosis is an infection that can cause erythema nodosum.

●A biopsy – In this test, the doctor takes a sample of tissue from 1 of the bumps. Another doctor looks at the tissue under a microscope. It can show if the bumps are erythema nodosum or something else. Most people do not need this test, but you might have it if your symptoms are unusual.

How is erythema nodosum treated? — Erythema nodosum usually gets better if the condition that is causing it goes away or is treated. As erythema nodosum gets better, the bumps start to look like bruises and then go away. They are usually gone in 2 to 8 weeks. Sometimes the bumps leave dark spots on your skin that can take months to go away. But they do not leave permanent scars.

While you have the bumps, there are some things you can do to help reduce the pain. You can:

●Raise your legs up while you are sitting

●Rest

●Wear special socks called "compression stockings"

If you still have pain, there are also medicines that can help. The most common medicines that people take are called "NSAIDs." NSAIDs are a large group of medicines that includes ibuprofen (sample brand names: Advil, Motrin), naproxen (sample brand names: Aleve, Naprosyn), and indomethacin (sample brand names: Indocin, Indocid).

Talk with your doctor or nurse about which medicines you should take and how much.

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