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:
- Something touching the skin.
- Heat or cold.
- An autoimmune reaction - the body over-reacting and causing damage to itself.
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).
Did you find this information useful?
- BSACI guideline for the management of chronic urticaria and angioedema; British Society for Allergy and Clinical Immunology (Feb 2015)
- Urticaria; NICE CKS, May 2016 (UK access only)
- Zuberbier T, Aberer W, Asero R, et al; The EAACI/GA(2) LEN/EDF/WAO Guideline for the definition, classification, diagnosis, and management of urticaria: the 2013 revision and update. Allergy. 2014 Jul 69(7):868-87. doi: 10.1111/all.12313. Epub 2014 Apr 30.
- Urticaria; DermNet NZ
- Urticaria and angio-oedema: an overview; Primary Care Dermatology Society
- Omalizumab for previously treated chronic spontaneous urticaria; NICE Technology Appraisal Guidance, June 2015
- Sharma M, Bennett C, Cohen SN, et al; H1-antihistamines for chronic spontaneous urticaria. Cochrane Database Syst Rev. 2014 Nov 14 (11):CD006137. doi: 10.1002/14651858.CD006137.pub2.
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