Hives, or urticaria as it is also known, is usually a red, raised and very itchy skin rash, similar to nettle rash. Hives are an allergic reaction triggered by an allergen of some kind. The causes of these allergic reactions can be as simple as contact with nettles or latex, as in latex gloves. It also can be a reaction to medications, insect bites, or, as we more commonly see, a reaction to certain foods. There are other types which react to extremes of temperature, sunlight or water on the skin.
Sometimes when there is an allergic reaction, the body releases histamine which causes the tiny blood vessels to produce fluid which rushes to the surface of the skin, causing acute swelling. Hence, anti-histamines are often recommended as the first line of treatment, not if you are pregnant though, to reduce the histamine that has been produced. This is simply symptom relief though and not finding the cause.
Hives are not contagious and usually the rash settles within a few days. Sometimes it can be limited to just a small part of the body or it can spread to several parts of the body, often the extremities such as arms, legs, feet, hands and face. 25% of people with acute urticaria (hives) also have angio-oedema, which is swelling in the deeper layers of the skin. The swelling sometimes causes a burning sensation and typically affects eyes, face and neck.
If the rash does not disappear after a few days, it is worth identifying what the trigger is likely to be. There is a simple process of skin prick tests, blood tests or some simple dietary changes that can be useful diagnostic tools in identifying the cause.
Once the cause or causes have been found, if avoidance or prevention is difficult, desensitisation treatment can be given to improve the bodies tolerance of the offending item/s.