Urticaria, commonly known as hives or the hives, is a rash often caused by an allergic reaction. Hives display as swollen red welts, which can range from the size of the head of a pushpin to several inches in diameter. Hives usually are harmless and go away without leaving any permanent marks on the skin. Hives can however be a quite uncomfortable condition, as the rash is sometimes very itchy.
What Causes Hives?
The immediate cause of hives is the release of histamine and other chemicals into the bloodstream from mast cells. In response to the histamine, blood plasma leaks from small blood vessels in the skin, generating the rash.
But the reasons the histamine and other chemicals are released in the first place are varied, and not always discoverable in a specific case. Most commonly it is due to a trigger to which the person is allergic. Such allergens include insect stings, substances in the air such as pet dander or pollen, foods such as shellfish or peanuts, or medications such as aspirin or penicillin.
In addition, for some people the histamine release that causes hives can be associated with such factors as heat, sunlight, rubbing on the skin, stress, exercise, or medical conditions and treatments such as lupus, cancer, hepatitis, HIV, or blood transfusions.
How Are Hives Treated?
The most effective thing to do with hives is to isolate the cause, and if it is an allergy, then avoid or remove the item to which one is allergic.
Often the cause will already be known, such as if a person has a history of developing hives after spending time around a cat, and has on this occasion just stayed a week at a relative’s house who has three cats.
If the cause is not known, a doctor may recommend an allergy skin test to try to identify the trigger. In this test, a very small quantity of purified allergen extracts of different kinds are scratched or pricked into the skin, and the reaction, if any, observed.
In addition to identifying and avoiding any allergen that may be causing hives, the most common treatment doctors recommend is an antihistamine. An antihistamine reduces the swelling, itching and other discomforts of hives.
There are non-prescription antihistamines such as Benadryll and Claritin, and stronger prescription antihistamines such as Vistaril and Clarinex.
Other recommendations for dealing with hives include:
* Keep the skin cool with cool, wet compresses, or take a cool bath. Adding baking soda or uncooked oatmeal to the bath water may help.
* Avoid alcohol, which can cause flushing of the skin.
* Do not scratch the skin in the area of the rash.
* Avoid wearing clothing that is tight, rough, or made of wool so as not to irritate the skin.
How Serious are Hives?
Generally hives are a minor and temporary discomfort, lasting a matter of hours or days. If hives become anything more significant than that, then one should seek medical attention.
Though hives tend not to be a serious problem, a related condition called angioedema can sometimes be quite serious. Angioedema affects deeper layers of skin. It often appears on the face, around the eyes and mouth, but can also develop elsewhere on the skin including the hands, feet, or genitals. What can be dangerous about angioedema is that it can also cause internal swelling, such as in the throat, intestines, or bowels. Severe angioedema can affect breathing by closing off air passages when the throat and tongue swell, which can cause loss of consciousness and even death in rare cases. So if one is experiencing not just an external rash, but swelling that is making breathing difficult, it is important to get to an emergency room for treatment.
“Allergies and Hives (Urticaria and Angioedema).” WebMD.
“Hives and Angioedema.” Mayo Clinic.
“Understanding The Hives.” Allergy Escape.