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Erythema nodosum

Erythema nodosum causes painful, tender, red or purple lumps under the skin, most often on the front of the shins. It is caused by inflammation of the fat layer under the skin. It is often a reaction to something else, such as a throat infection, some medicines, pregnancy, inflammatory bowel disease or sarcoidosis.

Last updated Nov 9, 2026

What it is

The lumps usually fade over 3 to 6 weeks, changing colour like a bruise. Finding and treating the trigger is important.

Rest, raising the legs and anti-inflammatory painkillers help.

Common signs

  • Painful red or purple lumps, usually on the shins
  • Lumps that change colour like a bruise as they fade
  • Fever, tiredness and joint pain

How it is usually diagnosed

  • Recognised by how it looks
  • Blood tests, a throat swab and a chest X-ray to look for a cause

Records worth keeping

Keeping these together makes each appointment easier, especially when you see a new doctor:

  • Test results
  • Notes on possible triggers
  • Photos of the lumps with dates

Questions to ask your doctor

  • What triggered it?
  • Do I need any further tests?
  • What should I do if it comes back?

When to get help right away

Call 112 or go to the nearest emergency department if you have:

  • There are no emergency signs specific to erythema nodosum; high fever or feeling very unwell needs prompt review

This page is general information. It is not a diagnosis and does not replace a doctor who knows your history. Medfold keeps your records organised; it does not interpret them.

Sources

Related conditions

Crohn's diseaseA lifelong condition in which parts of the digestive system become inflamed, causing flare-ups of diarrhoea, tummy pain and tiredness.SarcoidosisA condition where small patches of swollen tissue form in organs, most often the lungs and skin. It often gets better by itself.TonsillitisInfection of the tonsils at the back of the throat, usually caused by a virus. It is common in children and usually gets better in a week.