How do hives start out

Not everyone responds to the same medicines, though, so it's important to work with the doctor to find the right one for you. If a non-drowsy antihistamine doesn't work, the doctor may suggest a stronger antihistamine, another medicine, or a combination of medicines.

In rare cases, a doctor may prescribe a steroid pill or liquid to treat chronic hives. Usually this is done for just a short period 5 days to 2 weeks to prevent harmful steroid side effects.

Anaphylactic shock and bad attacks of hives or angioedema are rare. But when they happen, they need immediate medical care. People with bad allergies should carry an injectable shot of epinephrine. The doctor will teach you how to safely give yourself an injection if you are at risk for a severe allergic reaction. Larger text size Large text size Regular text size. What Are Hives?

What Causes Hives? An allergic reaction can cause hives, as can: temperature extremes stress infections some illnesses In some cases, a person has hives and angioedema, a condition that causes swelling around the eyes, lips, hands, feet, or throat.

Common allergies include: foods, especially shellfish , peanuts , tree nuts, milk, and fruit medicines antibiotics and allergy shots pets and other animals pollen insect bites and stings Sometimes a breakout of hives has nothing to do with allergies.

Other causes include: infections, including viruses exercise anxiety or stress sun exposure exposure to cold, such as cold water or snow contact with chemicals scratching dermatographia putting pressure on the skin, such as from sitting too long or carrying a heavy backpack over a shoulder Hives due to physical causes such as pressure, cold, or sun exposure are called physical hives.

The hallmark red raised welts are the main sign of hives. The welts can: have a pale center appear in clusters change shape and location in a matter of hours be tiny or as big as a dinner plate itch, sting, or cause a burning sensation Someone who also has angioedema might have puffiness, blotchy redness, swelling, or large bumps around the eyes, lips, hands, feet, genitals, or throat.

You get hives when something causes high levels of histamine and other chemicals to be released in your skin. This is known as a trigger. Try to find out what triggers hives for you, so you can avoid those triggers. This may help prevent an episode of hives.

Page last reviewed: 13 April Next review due: 13 April Check if you have hives Hives can be raised, red patches. 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.

Pressure or constriction. Delayed pressure urticaria can appear as red swelling six to eight hours after pressure belts or constrictive clothing, for example has been applied. Symptoms can also occur in parts of the body under constant pressure, such as the soles of the feet. Change in temperature. Cold urticaria is caused by exposure to low temperatures followed by re-warming.