Alternate Names : Urticaria
Hives are red, itchy welts on the skin that come and go over the course of minutes or hours. All types of hives can cause itching. They usually form on the skin but sometimes hives form in the soft tissue of the mouth, eyes and throat.
What is going on in the body?
Hives are the result of an allergic reaction in the skin. They are caused by the release of histamine. Histamine is released when a person's immune system tries to fight a foreign substance. The release of histamine causes inflammation in the skin.
What are the causes and risks of the condition?
There are several known factors that cause histamines to be released, and hives to form. These include:
allergy to medications or substances in the environment
acute or chronic infections
underlying systemic disease such as asthma, a condition that causes inflammation and obstruction of the airways in the lungs
blood products given intravenously, or into the vein
heat or cold
exposure to sunlight
Anaphylaxis is a medical emergency that can cause difficulty breathing and lead to death. It is important to call 911 immediately if anaphylaxis is suspected.