Hives (Chronic Urticaria)

Urticaria (also known as nettle rash) is an itchy rash caused by tiny amounts of fluid that leak from blood vessels just under the skin surface. In chronic urticaria, it persists for more than six weeks, although often on and off.

If you have hives (urticaria), you have an itchy rash with raised areas called weals (or wheals), which are white or red. There may be blotchy areas. The rash tends to come and go and it may move around.

In some people with hives, more serious swelling can develop - for example, in the mouth, or tongue or face. This related condition is called angio-oedema, and is discussed in a separate leaflet. It can get in the way of breathing and can be a medical emergency.

Possible causes include:

  • Allergy.
  • Something touching the skin.
  • Heat or cold.
  • Exercise.
  • Sunlight.
  • An autoimmune reaction - the body over-reacting and causing damage to itself.
  • Stress.
  • Infections.

See separate leaflet called Hives (Inducible Urticaria). This gives you further information about the type of hives which is caused by a physical stimulus (such as touch, heat, cold, vibration, etc).


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Dr Mary Harding
Peer Reviewer:
Dr Helen Huins
Document ID:
4449 (v42)
Last Checked:
30 December 2016
Next Review:
30 December 2019

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.