What is hives

Sometimes the hives may change shape or form together and create a larger, raised area. Hives can occur in a variety of places on the body. Call or seek medical attention immediately if you develop a hive outbreak around your throat or on your tongue or have trouble breathing along with hives.

The most common causes of hives are allergic reactions. These can be caused by any allergen you might be sensitive to, including:. Mild cases of hives caused by allergies are typically treated with long- or short-term allergy medications and avoidance of the trigger. Anaphylaxis is a severe, life-threatening allergic reaction. In this condition, hives are often accompanied with breathing difficulties, nausea or vomiting, severe swelling, and dizziness.

Call immediately if you suspect anaphylaxis. Also called chronic urticaria, this condition is marked by recurring hives that can interfere with your lifestyle. According to the Mayo Clinic , these can last between six weeks and several months or years. While not life-threatening, this form of hives can be uncomfortable and difficult to treat. They may also be a symptom of an underlying health problem, such as:. This form of acute hives is considered mild.

Excessive scratching or continuous pressure on the skin causes it. Dermatographism usually clears up on its own in a short period of time without treatment. Sometimes changes in temperature can induce hives in people who are sensitive to such changes. Cold-induced hives may occur from cold water or air exposure, while body heat from physical activity may cause exercise-induced hives. Exposure to sunlight or tanning beds may also bring about solar hives in some people.

Both viral and bacterial infections can cause hives. Common bacterial infections causing hives include urinary tract infections and strep throat. Viruses that cause infectious mononucleosis, hepatitis, and colds often cause hives. The first step in getting treatment is to figure out if you actually have hives.

In most cases, your doctor will be able to determine if you have hives from a physical exam. Your skin will show signs of the welts that are associated with hives. Your doctor may also perform blood tests or skin tests to determine what may have caused your hives — especially if they were the result of an allergic reaction.

In these circumstances, your doctor might suggest that you seek temporary relief by:. Simple changes to your lifestyle may be able to help you prevent hives from reoccurring in the future.

If you have allergies and you know which substances are likely to cause an allergic reaction, your doctor will suggest that you avoid any possible exposure to these factors. Allergy shots are another option that may help you reduce the risk of experiencing hives again. If the cause of hives can be identified, the best treatment is to avoid the trigger or eliminate it:. Some cases of hives last for more than six weeks and can last months or years.

This condition is known as chronic hives. If the cause cannot be identified, even after a detailed history and testing, the condition is called chronic idiopathic urticaria. Chronic hives may also be associated with thyroid disease, other hormonal problems or, in very rare instances, cancer. Even this condition usually dissipates over time.

In physical urticaria, the hives have a physical cause, such as exposure to heat, cold or pressure. Inflammation of the blood vessels, or vasculitis, can also cause hives. These hives are more painful than itchy, may leave a bruise on the skin and often last more than a day. Find answers with an allergist. Hives Hives, also known as urticaria, affects about 20 percent of people at some time during their lives. On this page. Whether your allergist suggests a treatment available only by prescription or an over the counter treatment will depend on several factors, including how uncomfortable the hives are making you.

Find expert care. Find an Allergist. Symptoms Symptoms can last anywhere from minutes to months — or even years. While they resemble bug bites, hives also known as urticaria are different in several ways: Hives can appear on any area of the body; they may change shape, move around, disappear and reappear over short periods of time. Allergist Stanley Fineman, MD.

Is It Hives or Angioedema? The following symptoms may indicate angioedema: Swelling in the eyes or mouth Swelling of the hands, feet or throat Difficulty breathing, stomach cramps or swelling of the lining of the eyes The best way to identify your symptoms is to talk to an allergist who can diagnose and treat both hives and angioedema. Diagnosis In some cases, the trigger is obvious — a person eats peanuts or shrimp , and then breaks out within a short time.

Management and Treatment Researchers have identified many — but not all — of the factors that can cause hives. Here are a few of the most common causes: Some food especially peanuts, eggs, nuts and shellfish Medications, such as antibiotics especially penicillin and sulfa , aspirin and ibuprofen Insect stings or bites Physical stimuli such as pressure, cold, heat, exercise or sun exposure Latex Blood transfusions Bacterial infections, including urinary tract infections and strep throat Viral infections, including the common cold, infectious mononucleosis and hepatitis Pet dander Pollen Some plants Antihistamines — available either over the counter or by prescription — are a frequently recommended treatment for hives.

Rubbing or scratching: Avoid harsh soaps. Frequent baths may reduce itching and scratching — beneficial because itching and scratching can make the hives feel worse.

Constant pressure: Avoid tight clothing. Pressure hives can be relieved by wearing loose-fitting clothes. Temperature: If you develop hives when exposed to cold, do not swim alone in cold water and always carry an epinephrine auto-injector.

Avoid exposure to cold air and use a scarf around your nose and mouth in cold weather. If you must be out in the cold, wear warm clothing.

Sun exposure: Wear protective clothing; apply sunblock. Medications: Notify your physician or pharmacist immediately if you suspect that a specific medication is causing your hives. Chronic hives Some cases of hives last for more than six weeks and can last months or years. Physical urticaria In physical urticaria, the hives have a physical cause, such as exposure to heat, cold or pressure.

Common triggers include: Rubbing or scratching. This is the most frequent cause of physical urticaria. Symptoms appear within a few minutes in the place that was rubbed or scratched and typically last less than an hour. The condition is considered chronic hives if the welts appear for more than six weeks and recur frequently over months or years.

Often, the cause of chronic hives is not clear. Chronic hives can be very uncomfortable and interfere with sleep and daily activities. For many people, antihistamines and anti-itch medications provide relief. Angioedema may cause large welts below the surface of the skin, particularly around the eyes and lips.

Chronic hives don't put you at any sudden risk of a serious allergic reaction anaphylaxis. If you do experience hives as part of a serious allergic reaction, seek emergency care. Signs and symptoms of anaphylaxis include dizziness, trouble breathing, and swelling of your lips, eyelids and tongue. The welts that come with hives arise when certain cells release histamine and other chemicals into your bloodstream.

Doctors often can't identify the reason for chronic hives or why acute hives sometimes turn into a long-term problem. The skin reaction may be triggered by:. In some cases, chronic hives may be related to an underlying illness, such as a thyroid disease or, rarely, cancer.

But if you do experience hives as part of a serious allergic reaction, seek emergency care. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version.