Erythema nodosum
Key facts
- Erythema nodosum causes painful red lumps, usually on your lower legs.
- It can be caused by many things including, bacterial infections, medicines and other health conditions.
- Your doctor can usually diagnose erythema nodosum by looking at your skin.
- Resting with your legs up, wearing support stockings and taking anti-inflammatory medicines can help ease your symptoms.
- Erythema nodosum usually goes away by itself within 6 weeks.
What is erythema nodosum?
Erythema nodosum is a skin condition. It causes red lumps, usually on your shins, ankles and knees.
Anyone can get erythema nodosum, but it's most common in people aged 20 to 40 years. It's also more common in females.
What symptoms are related to erythema nodosum?
Painful red lumps, or nodules, appear on your legs, from the knees down. Occasionally, they can also appear on your thighs, upper arms or face.
The lumps start off bright red, or darker than your normal skin colour. With time, they become flatter and turn purple or dark red, like a bruise. They usually fade away and don't leave a scar.
Other symptoms can include:
- swollen ankles
- fever
- feeling unwell
- aching joints
- diarrhoea
- abdominal (tummy) pain
CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.
What causes erythema nodosum?
Erythema nodosum happens when the layer of fat under your skin becomes inflamed or irritated.
It can be triggered by:
- a reaction to medicines, such as the oral contraceptive pill
- bacterial infections — such as streptococcal ('strep') throat or tuberculosis (TB)
- pregnancy
It can also happen in people who have:
- inflammatory bowel disease, such as Crohn's disease or ulcerative colitis
- cancer — lymphoma and leukaemia
- sarcoidosis
Doctors can't find the cause of erythema nodosum in about 1 in 2 people.
When should I see my doctor?
See your doctor if you have a skin condition that affects your daily life. You should also see your doctor if you have lots of lumps on your skin.
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.
How is erythema nodosum diagnosed?
Your doctor will ask about your symptoms and look at the lumps on your skin.
Your doctor might also organise some tests to check if another illness is causing your erythema nodosum.
These tests may include:
- blood tests
- a throat swab to check for streptococcal infection
- a chest x-ray
Sometimes your doctor will take a biopsy of your skin to check that the diagnosis is right.
ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.
How is erythema nodosum treated?
If your doctor can't find a cause of your erythema nodosum, you will be advised to wear compression stockings and rest with your legs elevated.
You can take anti-inflammatory medicines to help with any pain.
In most people, erythema nodosum clears up by itself within 2 to 6 weeks. Your pain and swelling may continue after this.
The cause of your erythema nodosum should be treated when possible.
Your doctor may recommend you take oral corticosteroids or use a steroid injection. In some cases, potassium iodide or colchicine tablets are prescribed.
What are the complications of erythema nodosum?
In some people erythema nodosum can return.
Very rarely ulcers (deep sores) can form. This may be due to trauma.
Resources and support
If you have a rash and you're not sure what to do, call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with you 24 hours a day, 7 days a week.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: November 2024
