In diagnosing hives, a very detailed history must be given to determine the duration of the hives. Hives can be either chronic or acute. Acute hives last for less than six weeks and chronic hives last longer than six weeks. Diagnosing chronic hives is more involved than diagnosing acute hives, but it is important to make the distinction as chronic hives can be caused by more serious underlying problems.
Chronic hives are known as physical urticaria when a specific stimulus triggers hives in certain people. According to Dermatolotgy.about.com, different types of urticaria include:
Dermographism – This type of physical hives is very common. The hives are produced suddenly by rubbing or stroking the skin.
Pressure Urticaria – This type is difficult to diagnose, but is fairly common. In this type, hives are produced hours after applying pressure to the skin.
Cholinergic Urticaria – Hives appear shortly after or during exercise.
Exercise Induced Anaphylaxis – Hives, shortness of breath, and dizziness after exercising are symptoms of this rare disorder. People with this disorder may pass out or go into shock.
Cold Urticaria – These hives are produced with exposure to cold water, ice, or sudden drops in temperature.
Solar Urticaria – Hives of this kind occur minutes after exposure to the sun and disappear soon after.
Steps in Diagnosis
It usually doesn’t take a lot for the doctor to diagnose the pink or red bumps or slightly raised patches of skin as hives. However, he will have trouble knowing for sure the cause, although with a detailed story, sometimes it is easy enough to figure out what triggered the reaction. If you get hives a lot, or you have a serious reaction, your doctor may send you to an allergy specialist.
You will probably be asked to make a list of family members who have allergic reactions. You will need to inform the physician about other health conditions that run in your family, or that you currently have because many types of conditions can be the underlying cause of hives or skin rashes. Sometimes your doctor or the allergy specialist will order a series of skin tests to find out what you are allergic to.
If you and your doctor have trouble identifying what is causing your case of hives, you should keep a journal to prevent future outbreaks. First make a list of external irritants that may have triggered your hives, such as new laundry detergents, soaps, and cosmetics. Next, you should list any foods or medicines that you have ingested. Continue keeping track until you can narrow down what is triggering your reactions.
