If you have a red, itchy rash on your skin, you may believe that you encountered poison ivy or something similar to it. You may also have a case of hives instead. Fortunately, hives are just merely uncomfortable and not dangerous. Hives result from inflammation that affects the skin. The medical term for hives is urticaria. Hives are usually red or skin-colored, and they can vary in size from a pea to a dinner plate. Hives are most often triggered by the release of histamines in the skin, which causes localized swelling, burning and itching. Hives can result from allergic reactions or may be due to many other conditions. Individual welts or spots usually will not last more than a day, though new hives may appear, and the general condition can last for weeks depending on the cause. Many hives may join together to form a very large welt. Scratching, compressing, heating or cooling hives excessively can worsen them. Though itchy and uncomfortable, hives are usually self-limiting and disappear on their own. In rare circumstances, hives can be a sign of a more serious allergic reaction. A visit to your health care professional may help to determine what triggered your hives, though the exact cause is usually difficult to determine. Hives are most commonly caused by an allergic reaction in which the immune system releases histamine into the bloodstream to fight the allergen. In essence, the immune system thinks there is a foreign substance (called allergens) in your system, and tells the body to release histamine to fight it off. This usually causes the red, raised bumps and swelling which can be quite painful unless a treatment for hives is taken. Most of the time the causes of hives remain unknown. There are certain things that are common causes though, or what are called triggers. In most cases, hives can last from about 1 day up to 6 weeks. Sometimes people have them frequently, and they may be diagnosed with chronic hives. Typically, chronic hives occur no less than twice per week. Usually, a doctor will only diagnose chronic hives if a person has frequent episodes for more than 6 weeks at a time. The causes of hives can be avoided mainly through trial and error. In order to prevent the breakout of hives, you should keep a journal of all the foods, medications and illnesses or activities that you’ve had prior to getting the hives. After a few cases of hives, your hives causes will be seen in the similarities between the cases. If you always get hives after being out in the direct sunlight for a few hours, your physical hives will then have a known allergen. In this way, you can avoid the allergen and be able to avoid the hives as well. Even though hives can cause a great discomfort, they are usually treatable. You can find a wide range of topical treatments and off the counter treatments as well. Antihistamines can block the action of the chemical mediators that are responsible for hives. Certain steroids may also be effective in reducing hives. Additionally, you can reduce the discomfort associated with hives by avoiding hot or cold water or tight-fitting clothing. A person may seldom have prolonged or frequent hives. In these cases, more powerful antihistamines are frequently prescribed. Certain antihistamines may cause drowsiness, and it is best to select a non-drowsy medication for infrequent hives. In rare cases, hives may be associated with difficulty breathing or swelling of the tongue. These are serious symptoms that could indicate a systemic allergic reaction known as anaphylaxis. Emergency treatment of these dangerous symptoms may include Corticosteroids and Epinephrine.