Urticaria
Definition
Pink lumpy rash on skin. Commonly known as "hives".
Epidemiology
Pathophysiology
Tends to be rather itchy, and is caused by a release of mediators from mast cells. Can be any cause of release, not just IgE - so not always allergic.
Some cases can last more than 6 weeks, and can be classified as Chronic Urticaria. They can be caused by autoimmune, cholinergic, dermographism, and lots of other scary, complication and unclear things. We don't think you need to know about them.
Risk Factors
- Infection
- Serum Sickness
- Medicines
- Food
- Temperature
May be allergic, as a reaction to medicines, foods and sometimes seen in anaphylaxis.
Clinical Features
Each area of swelling usually lasts less than 24 hours - if lasting more than 24 hours, consider angioedema!
Its a transient pink or pale swelling due to plasma leakage. Often referred to as "hives". Urticaria is not usually an allergic condition, although it is usually thought to be.
Investigations
Often will setlle without a cause being found, but skin prick testing can identify a cause.
Management
Anti-histamines, and avoiding a cause.
Prognosis
90% will settle within 6 weeks. If not settling, will need to be referred to Dermatology, for treatment of chronic condition.