Hives are very common with 10-20 percent of the population having at least one episode in their lifetime. Hives can sometimes occur in deeper tissues of the eyes, mouth, hands or genitals. These areas may develop a swelling that is frightening in appearance, but usually goes away in less than 24 hours. This swelling is called angioedema.
In many cases, a single attack of hives is due to an infection or virus and these go away within a few days to a few weeks. Some people get repeated attacks that occur as an allergic reaction to a variety of things (foods, most commonly nuts, chocolate, fish, tomatoes, eggs, fresh berries and milk, insect stings, and medications). In this case, they usually break out within a few hours of the exposure. Usually, the patients figure out the cause by themselves, and they never bother coming to a doctor.
Certain people can develop recurrent hives from sunlight, cold, pressure, vibration or exercise. These are called the physical urticarias. If hives develop from scratching or firmly rubbing the skin it is called dermatographism. It is the most common of the physical urticarias and it affects about 5 percent of the population. It doesn't always itch. This condition sometimes also occurs along with other forms of hives.
Some people react to anything that makes them hot or sweaty with hives. This can be sunlight, exercise, hot baths, blushing or anger. These are tiny intensely itchy hives with a big red blotch around them and are called cholinergic urticarial.
Pressure urticaria shows up as a deep welt in an area of prolonged pressure. Occasional people react to the cold. Even more rare is a reaction to sunlight.
Occasionally, a person will continue to have hives for many years. These hives, called chronic urticaria, can be one of the most frustrating problems dermatologists see in their patients. This is defined as hives lasting longer than 6 weeks. Patients like this come in miserable and worried with this problem, often having seen multiple specialists. Neither the patient nor the doctor can determine the cause of the hives. Patients will often say, "It has got to be something causing these hives." The truth is hard to accept for some patients.
In the overwhelming majority of cases it is not "something" causing the chronic hives, it is "nothing." That is, in about 95% of chronic hives cases, the hives are "idiopathic" (a medical term that means there is no discernible cause). Because of those 5% of cases with a cause, it is worthwhile to see a physician to determine if any underlying disease is present (e.g. thyroid problems, liver problems, skin diseases, sinusitis) or if there is an allergic cause (i.e. a reaction to a drug, insect, food, etc.). This can be accomplished by a good history and physical, a few blood and urine tests and sometimes a skin biopsy. Some patients with chronic hives and elevated anti-thyroid antibodies in the blood improve when given thyroid supplement even if the thyroid function is normal.
In about half of patients with chronic idiopathic hives, the explanation is that body's immune system is, in a sense, overactive. The urticaria is "autoimmune". The immune system is attacking the normal tissues of the body and causing hives as a result. We know certain urticaria sufferers have other signs of autoimmune problems. Some have autoimmune thyroid disease, vitiligo, swollen joints, or certain abnormalities in the blood (especially the ANA test). A new treatment has recently emerged for autoimmune urticaria. This is the use of hydroxychloroquine, a drug originally used for malaria. In a clinical trial 83% improved or cleared completely when used for three months or more.
So, in many patients with chronic hives, there is really no exposure (drug, food, insect, chemical) to blame for the urticaria. The patient must understand and accept this for their ideal management. Basically, all that needs to be done is treat the hives. The main treatment of hives is antihistamines, and they will work if they are used properly. Common reasons for lack of effectiveness of antihistamines are 1) the particular antihistamine used is not strong enough 2) the antihistamine is not used in a high enough dose 3) the antihistamines are not continued for a long enough period.
The most well tolerated initial treatment are the non-sedating antihistamines like fexofenadine, loratidine, and cetirizine. If these don't eliminate the hives, a sedating-type of antihistamine (diphenhydramine, hydroxyzine, cyproheptadine or doxepin) is added at night. High doses may be needed and this will cause sedation. Fortunately, most patients will become less affected by sedation after they have taken the drug regularly for a while.
If that doesn't work, some doctors may try a short course of cortisone (steroids) to clear the hives completely. Then the patient can maintain the effect with the much safer antihistamines, since steroids have significant side effects if used long term.
A drug used for psoriasis and kidney transplants, cyclosporin, is almost always effective in clearing even the most severe cases of chronic hives at low doses. However, it causes significant side effects if taken for a long time.
There are other medications that may be added to the antihistamines, but these non-standard therapies are not always effective. However, if the hives are not responding, they are worth a try. Examples are anti-acid pills (cimetidine, ranitidine), dapsone and sulfasalazine (anti-inflammatory antibiotics), nifedipine (a blood pressure medicine), Accolate (an asthma drug), colchicine (a drug for gout), and several others.
The important thing is that the patient is given enough medication (antihistamines, perhaps in conjunction with other drugs) to suppress the hives. Whatever it is that controls a patients hives, should be the daily regimen, taking the drugs every day, whether or not they have the hives on any given day. The idea is that one is preventing the hives from breaking out.
Some doctors suggest that medications should be continued for long periods - perhaps even a month after the hives have disappeared. Again, the exception to this is the cortisone/steroid-type medications, which should only be used for short periods initially to quiet down the urticaria. Remember that one must work closely with their doctor to find a medication regimen that suppresses the hives until they resolve on their own.
Back to Index
The medical information provided in this site is for educational purposes only and is the property of the American Osteopathic College of Dermatology. It is not intended nor implied to be a substitute for professional medical advice and shall not create a physician - patient relationship. If you have a specific question or concern about a skin lesion or disease, please consult a dermatologist. Any use, re-creation, dissemination, forwarding or copying of this information is strictly prohibited unless expressed written permission is given by the American Osteopathic College of Dermatology.