While there are a variety of causes of hives, the main reason people break out in hives is usually due to an allergic reaction to a variety of foods, medicines, plants or animals.
Each year about 15% of the US population experiences hives–either on the skin (urticaia) or a swelling of the throat tissues (angioedema) due to allergic reactions. Hives are an allergic reaction due to environmental forces or something taking place within the body. The reaction is generally characterized by raised, itchy patches on the skin (wheals) that are always elevated above the surrounding areas.
Wheals are defined as raised area on the skin that last only a short period of time, are most often red and itchy, with pale interiors (due to the swelling) and a more defined red border around the outside edges. Hives are also known to breakout in smaller welts or individual red lumps.
Many allergens can trigger allergic reactions that cause outbreaks of hives. Often it is repeated exposure to common allergens such as the occupational exposure of bakers to flour and other products they commonly use. Another example might be landscapers or others who work outdoors being more likely to become allergic to pollen.
A common cause of hives occurs in response to the body’s own production of antibodies. While these proteins are produced by the immune system to fight foreign substances—specific viruses or bacteria that enter the body, for some reason (often remaining unknown) the body has a reaction to the process.
This may happen as the result of a certain disorder (thyroid), a blood transfusion or an infection on any scale from hepatitis down to the common cold. Actually infections such as viral upper respiratory are often causes of hives in children. In adults, many bacterial and fungal infections are at the root.
Acute cases of hives can occur due to animal dander. This happens because animals secrete oily fluids from their skin that contain allergens (dander). Sensitive people often have allergic reactions to the build-up of these oils on the fur or feathers of their pets as well as proteins in the animal’s saliva.
Bites or stings from insects such as wasps, the honeybee, hornets or yellow jacket along with fire ants are common trigger of allergies resulting in hives. Though allergies of this type can affect anyone, children in the spring and summer are most often affected. Another outdoor allergy is pollen (summer, fall or spring) as plants are always releasing these tiny particles into the air as a means of reproduction. Culprits include allergens from certain trees, ragweed and many grasses.
Latex, a form of rubber, is another substance found to trigger hives in many people. It is the proteins found in products such as rubber gloves or condoms that trigger the reaction causing hives or a more severe potentially life-threatening reaction called anaphylaxis.
There is a skin test commonly used to determine whether sufferers are allergic to certain substances—mold, animal dander, dust mites, etc. Throughout the testing, skin is exposed to different allergens and then observed as to their reactions. If the allergens trigger a reaction symptoms like those of hives will develop.