What is urticaria?
Urticaria, also known as hives, is a common allergic disorder in which a red, itchy, lumpy skin rash appears ‘out of the blue’. These skin lumps, which are known as wheals, can develop anywhere on the body. The wheals, which have pale centres and red margins, can spread out and join up to form large irregular patches. They are usually about 1 to 5 cm across. These wheals can rapidly change shape and come and go over a period of minutes or hours.
Who gets urticaria?
Urticaria can affect any person at any age. One out of every 5 people will have an attack at some stage in their lives. The allergy can be present at birth or develop slowly over many years or appear suddenly on exposure to the allergens.
What causes urticaria?
Urticaria is a type of allergy resulting from a release of a chemical called histamine. The cause of this histamine release is often unknown, but common causes are foods, drugs and infestations. Sometimes the cause is very obvious, such as when urticaria appears minutes after eating. Exposure to heat, cold and overexposure to sunlight can cause urticaria.