|Hives may come in two different forms – the ACUTE, which can last from a few hours to less than six weeks, and the CHRONIC, which lasts for longer than six weeks. The welts may disappear and then reappear after a short time. Scratching these hives will make them worse, so it is important to avoid this natural tendency.
In many cases, no apparent cause is found for hives even after intensive investigation by a specialist may be required.
Allergic reactions to foods, drugs, insect stings, latex, cold air, sunscreens, ultraviolet light and x-ray dyes often cause Acute urticaria.
Viral infections such as the common cold, strep throat, infectious mononucleosis, ort hepatitis, could induce this reaction.
In someone who is prone to hives, the triggers will cause the body to release chemical mediators, including histamine, which causes a runny nose and watery eyes. Histamine dilates the blood vessels and allows fluid to leak into the surrounding tissues… the result is itching and swelling.
In many people the cause is quite clear – eating strawberries or shrimp may produce an outbreak of hives. In other cases, the patient may not be able to associate any food or substance with the outbreak.
An allergist will try to determine the cause of the problem and may ask that you keep a diary of your foods and lifestyle so that it is easier to pin down which trigger may be the culprit. It may also be necessary to have some blood tests taken, an urinalysis, or skin tests.
Depending on the severity of your hives, your doctor will prescribe treatment, and this could be an antihistamine for a milder case or an injection of epinephrine for a severe attack.
If a cause has been found, it is imperative to avoid that food, medication, or substance to prevent further attacks. This may involve careful reading of all labels on foods, asking about ingredients when eating out, determining what may be in over-the-counter and prescription drugs by asking your pharmacist, and avoiding substances in the workplace or the home, which can cause an outbreak.
Some people may also react to the sun; protective clothing and sunscreen lotions should be applied. It is also a good idea to wear loose fitting clothing as any pressure can aggravate urticaria.
Anaphylaxis is a word that describes a life threatening reaction to a substance and in such conditions there could be a drop in blood pressure, wheezing, difficulty breathing, loss of consciousness, and shock; where there is any danger of such collapse with urticaria, epinephrine should be given. Anyone who has experienced such reactions with urticaria should carry an emergency first aid kit with epinephrine which can be self injected.