Urticaria (Hives)

Urticaria, commonly called hives, is a condition where wheals (large red itchy raised areas) appear on the skin suddenly, and do not last in any one spot for longer than 24 hours.  Many wheals or hives can appear at once, and they can move around the skin of the body over several days. They can be very itchy, and sometimes they are even painful.  Along with the raised area (the wheal), the skin may have a larger red patch (called a flare).  Hives typically have both a wheal and a flare.

Urticaria can happen in people of all ages and races, and it is somewhat more common in women.  When the urticaria occur at least twice a week for less than 6 weeks, they are referred to as acute urticaria, and when they appear at least twice a week for more than 6 weeks, they are called chronic urticaria.  This distinction is important because acute urticaria are more often due to upper respiratory infections and medications than other causes.  If the urticaria do not occur at least twice a week, then they are called “episodic” urticaria and are somewhat more likely to have an environmental or food trigger than could be identified through a diary of foods eaten and environments encountered around the time of the outbreak.

The cause of chronic urticaria is usually very difficult to find.  Most of the time, we do not find a cause for chronic urticaria.   Many cases are felt to be due to an autoimmune process in the patient’s immune system.

Physical urticarias are a special subset that occur in areas of pressure, vibration, or temperature change.  Some people get “cholinergic urticaria”, which are small wheals about 2-3 mm in diameter and occur within 15 minutes of sweating or heat, or sometimes with alcohol.  Cold urticaria can occur in cold exposed areas minutes after the skin is rewarmed.  Some people can have solar urticaria when they are exposed to light or the sun.  Some people develop hives or urticaria when they come into contact with water.

You may find it helpful to keep a diary of foods and activities for several weeks, to see if you can pinpoint something that occurs on the days that you have urticaria.  Sometimes, seemingly unimportant occurrences can be the trigger for urticaria, such as the dye in a type of snack you eat on some days, or there may be a food you were never allergic to previously that suddenly starts causing urticaria.  Often, the only way to discover this is to notice a pattern on a food or activity diary kept over weeks.

The treatment of urticaria is often unsatisfactory.  The first step in treatment is to try to find any possible triggers for the urticaria, usually through a diary.  In addition, to help with the symptoms of the urticaria, we use multiple antihistamines to decrease the severity of the hives.  You will likely be given several non-sedating (non-drowsy) antihistamines to use in the morning, and more sedating (drowsy) antihistamines at night.  These are meant to be taken every day to try to help prevent the urticaria from occurring and to make those that occur less severe.

When antihistamines do not help, we will sometimes use ultraviolet light therapy, given 3 times a week in the doctor’s office, to help with urticaria.  This is time consuming and is generally used only in severe cases of urticaria that are causing a disruption in a patient’s life.