Hives, also known as urticaria, are itchy, raised welts that are found on the skin. They are generally red, pink, or flesh-colored, and sometimes they sting or hurt. In most cases, hives are caused by an allergic reaction to a medication or food or a reaction to an irritant in the environment.
In many cases, hives are an acute (temporary) problem that may be alleviated with allergy medications. Most rashes go away on their own. However, chronic (ongoing) cases, as well as hives accompanied by a severe allergic reaction, are larger medical concerns