What are hives (urticaria)?
Hives, also known as urticaria, 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.Â 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.Â Along with the raised area (the wheal), the skin may have a larger red patch (called a flare).Â Hives typically have both a wheal and a flare.
Who gets hives and what is the cause?
Hives can occur in people of all ages and races, and it is somewhat more common in women. When the hives occur at least twice a week for less than six weeks, they are referred to as acute hives, and when they appear at least twice a week for more than six weeks, they are called chronic hives.Â This distinction is important because acute hives are more often due to upper respiratory infections and medications than other causes.Â If the hives do not occur at least twice a week, then they are called âepisodicâ hives and are somewhat more likely to have an environmental or food trigger. The trigger can possibly be identified through a diary of foods eaten and environments encountered around the time of the outbreak.
The cause of chronic hives is usually very difficult to find.Â Most of the time, we do not find a cause for chronic hives.Â Many cases are felt to be due to an autoimmune process in the patientâs immune system.
What are physical hives?
Physical hives are a special subset that occurs in areas of pressure, vibration, or temperature change.Â Some people get âcholinergic hivesâ, which are small wheals about 2-3 mm in diameter and occur within 15 minutes of sweating or heat, or sometimes when alcohol is consumed.Â Cold hives can occur in areas of the skin exposed to cold minutes after the skin is re-warmed.Â Some people can have solar hives when they are exposed to light or the sun. Some people develop hives, or urticaria, when they come into contact with water.
How can a food or activity diary help?
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 hives. Sometimes, seemingly unimportant occurrences can be the trigger for hives, 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 hives.Â Often, the only way to discover this is to notice a pattern on a food or activity diary kept over weeks.
How are hives treated?
The treatment of hives is sometimes difficult.Â The first step in treatment is to try to find any possible triggers for the hives, usually through a diary.Â In addition, to help with the symptoms of the hives, we use multiple antihistamines to decrease the severity.Â You will likely be given several non-sedating (non-drowsy) antihistamines to use in the morning, and more sedating (drowsy) antihistamines at night.Â These are meant to be taken every day to try to help prevent the hives from occurring and to make those that occur less severe.
When antihistamines do not help, ultraviolet light therapy is sometimes recommended. A patient receives treatment three times a week to help with hives.Â This is time consuming and is generally used only in severe cases of hives that are causing a disruption in a patientâs life.
For more information, or to set up a consultation with Dr. Jennifer Janiga to discuss evaluation of and treatment for hives in our Reno/Tahoe dermatology and plastic surgery office, please send us an email or call 775-398-4600. Appointment length varies but is usually not more than 15-30 minutes.