Hives (urticaria) are raised, itchy bumps or welts on your skin. In people with darker skin, the hives may be skin-colored, reddish, brownish, or lighter-colored than the surrounding skin. In people with lighter skin, the hives may be pink or red.
The allergy specialists at UPMC offer diagnostic testing and treatment for hives in children and adults.
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What Are Hives?
The main symptom of hives is raised, itchy bumps or welts on your skin. In people with darker skin, the hives may be skin-colored, reddish, brownish, or lighter-colored than the surrounding skin. In people with lighter skin, the hives may be pink or red.
Hives can be different shapes and sizes and appear as individual hives or in groups. Hives may be localized and affect only one area of your body, or they can affect several areas or your entire body.
What are the types of hives?
There are several types of hives, including:
- Acute hives — Last less than six weeks and may be caused by an allergic reaction.
- Chronic hives — Happen at least twice a week for longer than six weeks, and may be caused by something other than an allergic reaction.
- Chronic, spontaneous hives — Chronic hives that have no obvious cause.
- Chronic inducible hives — Chronic hives that occur due to an environmental trigger, such as high or low temperatures, sunlight, pressure, scratching, exercise, or sweating.
How common are hives?
Hives are very common. According to the American Academy of Allergy, Asthma, and Immunology, about one-quarter of the population will have acute hives at least once in their lives, and about 1% of the population has been diagnosed with chronic hives.
What causes hives?
An allergic reaction is a common cause of hives.
Allergic reactions occur when your immune system reacts to a trigger such as:
- Animal dander.
- Food.
- Insect stings or bites.
- Medication.
- Pollen.
Other causes of hives include:
- Stress.
- Exercise.
- Exposure to hot or cold temperatures.
- Exposure to sunlight or water.
- Illness or infection.
- Sweating.
In some cases, your doctor may not be able to determine what caused your hives.
What can suddenly cause hives?
Some cases of hives that appear suddenly are caused by an allergic reaction. However, hives caused by illness, infection, stress, and environmental triggers can also appear suddenly.
Hives risk factors
You may be at higher risk of developing hives if you have a history of allergies, including allergies that cause symptoms such as itchy eyes, sneezing, or a runny nose.
Complications of hives
If a severe allergic reaction causes hives, you could develop a condition called anaphylaxis. Anaphylaxis causes swelling of your airways and low blood pressure. Without immediate treatment, anaphylaxis may be life-threatening.
How can I prevent hives?
There is nothing you can do to prevent hives. However, if you have known allergies or triggers, avoiding exposure to those substances or conditions can reduce your risk of developing hives.
What Are the Signs and Symptoms of Hives?
The main symptom of hives is raised, itchy bumps or welts on your skin. In people with darker skin, the hives may be skin-colored, reddish, brownish, or lighter-colored than the surrounding skin. In people with lighter skin, the hives may be pink or red.
Hives may be different shapes and sizes, and they may disappear and reappear within minutes or hours.
How long does it take for hives to go away?
Acute hives typically go away on their own within 24 to 48 hours. However, acute hives may go away and reappear — or appear in a new area of your body — for several days or weeks until they go away completely. Chronic hives last six weeks or longer.
When should I see a doctor about my hives?
Mild cases of hives are typically harmless and will disappear on their own. If you have a mild case of hives that lasts for more than a few weeks without going away, you should schedule an appointment with your doctor to determine the cause.
Severe cases of hives that are caused by an allergic reaction could be a sign of a life-threatening condition called anaphylaxis. If your hives are severe or are causing symptoms that affect your ability to breathe, dial 911 or go to the nearest hospital Emergency Department.
How Do You Diagnose Hives?
Your doctor can diagnose hives by examining your skin. Your doctor will also ask you about any known allergies, as well as any exposures to allergens or other triggers that may have caused your hives.
What to expect during your visit
If your doctor suspects hives, they will:
- Perform a physical exam.
- Ask you about your symptoms.
- Ask about possible allergic reactions or other triggers.
- Ask about your medical history and medications.
- Order skin and/or blood tests.
Tests to diagnose hives
If your doctor suspects that your acute hives may be caused by an allergic reaction, they may order tests including:
- Blood tests for allergies — Look for antibodies in your blood that could point to an allergic reaction.
- Skin tests for allergies — Also known as a skin prick or scratch test, this test checks for reactions to a variety of allergens by placing a drop of allergen under your skin.
Hives prognosis
For most people, hives are uncomfortable but harmless. Most cases of acute hives resolve in a few weeks, and most cases of acute hives resolve within a year.
If hives are caused by an allergic reaction, you may need to avoid allergy triggers, take allergy medication, get allergy shots, or carry an epinephrine injector in case you develop anaphylaxis.
How Do You Treat Hives?
Most cases of hives are mild and go away without treatment.
If treatment is necessary, your doctor may recommend:
Lifestyle changes
Your doctor may recommend lifestyle changes that help you avoid any known hive triggers, including allergens, hot or cold temperatures, or extreme stress.
Medication
Your doctor may recommend medications to treat hives caused by an allergic reaction, including:
- Antihistamines — Block the effects of histamine, a chemical that your body releases in response to allergy triggers.
- Steroids — Reduce your body’s immune response to allergy triggers.
- Epinephrine — An injectable emergency medication that treats life-threatening symptoms caused by anaphylaxis.
- Xolair (omalizumab) — An injectable medication for hives that are not controlled by taking antihistamines or steroid medications.
If your hives are caused by an illness or infection, your doctor may prescribe other medications to treat the underlying cause.
Allergy immunotherapy (allergy shots)
Allergy immunotherapy, also known as allergy shots, works by introducing your body to small amounts of allergens so your immune system can build up a tolerance. Over time, your doctor will gradually increase the amount of allergens in your shots so your body begins to recognize the substance as harmless.
Why Choose UPMC for Hives Care?
When you choose UPMC for hive care, you will receive:
- Access to world-class allergy and immunology expertise — Our world-renowned experts treat all types of allergies using the latest approaches and therapies.
- A full range of treatment options — We offer evidence-based allergy treatments that improve your symptoms and reduce your risk of complications.
- Multidisciplinary care — We partner with primary care providers, ear, nose, and throat specialists, dermatologists, and other medical experts to provide complete care that optimizes your quality of life.
