In short

Urticaria, commonly known as hives, affects about 20 percent of people at some time during their lives, causing intensely itchy, raised welts that appear suddenly and can last from minutes to months or even years.

What is urticaria?

Urticaria is a skin condition that causes itchy, raised bumps or patches on your skin. These bumps are also called wheals or welts. The bumps can be red or the same color as your skin, depending on your skin tone. The condition happens when your body releases a substance called histamine, which is a protein your immune system produces in response to something it sees as a threat.

The welts can appear anywhere on your body, including your face, arms, legs, chest, or back. They can be as small as a few millimeters or as large as a dinner plate. The patches of hives often join together to form larger swollen areas.

Urticaria is very common. Around 20 percent of people will experience hives at least once in their lifetime. The condition can affect anyone at any age and often appears without warning.

Symptoms of urticaria

The main symptom of urticaria is the appearance of raised bumps on your skin. These bumps have specific characteristics that help identify them:

Raised, itchy bumps that can be red or skin-colored
Bumps that vary in size and shape
A feature called "blanching" — when you press the center of a red hive, it turns white
Intense itching that may worsen with scratching, alcohol, exercise, or emotional stress

Individual hives typically last less than 24 hours. They appear and fade repeatedly, moving around your body and changing shape. The bumps don't leave bruises or scars when they disappear.

Some people with urticaria also develop angioedema, which is swelling that occurs deeper in the skin. This swelling usually affects the face, lips, eyes, hands, feet, or genitals. Unlike the surface welts of hives, angioedema can be painful rather than itchy. Swelling in the throat or tongue requires immediate medical attention because it can make breathing difficult.

Types of urticaria

Doctors classify urticaria based on how long it lasts and what triggers it.

Acute urticaria

Acute urticaria refers to hives that last less than six weeks. This is the most common type and is between ten and one hundred times more common than chronic urticaria. Acute urticaria is usually self-limited and often goes away on its own.

Chronic urticaria

Chronic urticaria is defined as hives that last longer than six weeks. The welts occur at least twice a week and can continue for months or even years. In many cases, chronic urticaria happens without an obvious cause. This is called chronic idiopathic urticaria or chronic spontaneous urticaria. Between 80 and 90 percent of chronic urticaria cases are idiopathic.

Physical urticaria

Physical urticaria, also called inducible urticaria, is triggered by specific physical factors. These triggers include:

Cold air or water
Heat or sunlight
Pressure on the skin
Vibration
Exercise or sweating
Scratching or rubbing the skin

Physical hives usually appear within an hour after exposure to the trigger.

What causes urticaria?

Urticaria happens when mast cells and basophils in your skin release histamine and other inflammatory substances. This release causes blood vessels to leak fluid into the surrounding tissue, creating the characteristic welts.

The triggers for acute and chronic urticaria are often different.

Causes of acute urticaria

In acute urticaria, a trigger can be identified in about 40 to 60 percent of cases. Common triggers include:

Foods, especially peanuts, eggs, nuts, shellfish, and milk
Medications, particularly antibiotics like penicillin, aspirin, and ibuprofen
Insect stings or bites
Infections, including upper respiratory infections, strep throat, urinary tract infections, and viral infections like the common cold, mononucleosis, or hepatitis
Latex
Blood transfusions
Pollen
Pet dander

In children, hives are often caused by viral infections, which is why they sometimes occur along with a cold or diarrhea.

Causes of chronic urticaria

Chronic urticaria is more likely to be associated with autoimmunity than with allergies. A trigger can only be identified in about 10 to 20 percent of chronic cases. Possible causes include:

Autoreactivity (the body's immune system reacting against itself)
Chronic infection
Intolerance to food additives

Despite common belief, stress rarely directly causes hives, but it can make symptoms worse. Hives that last for days at a time are almost never due to an allergy, except in some cases of medication allergy.

How is urticaria diagnosed?

Doctors diagnose urticaria based on your symptoms and a physical examination of your skin. The diagnosis is clinical, meaning your doctor can usually tell by looking at your rash and talking to you about when and how it appeared.

One key feature that helps identify urticaria is that the welts come and go randomly, with each spot usually lasting less than 24 hours. The bumps also show blanching when pressed.

Your doctor may ask you to keep a diary to track:

Your activities
Any medicines, herbal remedies, or supplements you take
What you eat and drink
Where hives appear and how long they last
Whether your hives come with painful swelling

Testing for chronic urticaria

An extensive workup is not recommended for diagnosing chronic urticaria unless elements of your history or physical examination suggest specific underlying conditions. If tests are needed, your doctor may order:

Complete blood count with differential
Erythrocyte sedimentation rate or C-reactive protein level
Thyroid-stimulating hormone level
Urinalysis
Liver function tests

If your doctor suspects urticarial vasculitis (a related condition where blood vessels become inflamed), they may perform a skin biopsy. This involves removing a small sample of skin tissue for testing in a laboratory.

Treatment and management

The treatment for urticaria focuses on relieving symptoms and, when possible, identifying and avoiding triggers.

Antihistamines

Antihistamines are the first-line treatment for both acute and chronic urticaria. They work by blocking histamine, the substance that causes itching and swelling.

Second-generation antihistamines are preferred because they cause less drowsiness and have fewer side effects than older antihistamines. These include medications like cetirizine, loratadine, fexofenadine, desloratadine, and levocetirizine. These medications are typically taken once a day.

If standard doses don't control your symptoms, your doctor may increase the dose up to four times the normal amount.

First-generation antihistamines like diphenhydramine (Benadryl) or hydroxyzine (Atarax) may be used at bedtime because they can make you drowsy. However, they are generally not recommended for regular use due to their side effects.

Additional medications

If antihistamines alone don't control your symptoms, your doctor may add other medications:

H2 blockers (like famotidine or ranitidine) may be added to H1 antihistamines. Several studies have found at least a modest benefit from this combination.
Leukotriene receptor antagonists (like montelukast) may be especially helpful in people with cold urticaria or intolerance to nonsteroidal anti-inflammatory drugs.
Doxepin, a medication with strong antihistamine properties, may be effective in difficult cases.
Short courses of oral corticosteroids (like prednisone) may help control severe cases of urticaria with extensive involvement and intractable itching. However, long-term use is discouraged because of side effects.

Biologic therapy

For chronic urticaria that doesn't respond to antihistamines, your doctor may prescribe omalizumab (Xolair). This medication is given as a monthly injection and is effective in approximately 80 percent of patients.

Dupilumab is another biologic medication approved for chronic urticaria in patients who don't respond to antihistamines. It is given as an injection, typically every two weeks.

Other treatments

For very difficult cases, your doctor may consider medications that modify your immune system, such as cyclosporine, tacrolimus, hydroxychloroquine, or mycophenolate.

A newer medication called remibrutinib, which is taken by mouth, was approved in 2025 for chronic urticaria that isn't controlled with antihistamines.

Prevention and lifestyle tips

The best way to prevent urticaria is to avoid known triggers. However, triggers can only be identified in a small percentage of people with chronic hives.

General self-care tips

Several lifestyle adjustments may help reduce symptoms and prevent flare-ups:

Avoid triggers when possible, including foods, medications, pollen, pet dander, or physical factors like extreme temperatures
Wear loose, soft clothing made of cotton. Tight or scratchy fabrics like wool can irritate your skin
Take cool showers rather than hot ones. Hot water can dry out and further irritate your skin. Limit showers to 10 minutes
Use fragrance-free moisturizers to keep your skin hydrated and build a protective barrier
Apply cool compresses to relieve itching
Avoid scratching even though it's tempting. Scratching can make hives worse

Managing stress

Stress is one of the biggest known triggers for chronic hives. While reducing stress may seem difficult, acknowledging the stress in your life is an important first step. Activities that may help manage stress include:

Yoga
Walking or other exercise
Progressive muscle relaxation
Breathing exercises
Meditation or mindfulness
Therapy

Getting enough sleep is also important, as lack of sleep can affect your immune system and increase stress reactions.

Temperature control

If you have temperature-related urticaria, you'll want to avoid extreme heat or cold. This includes:

Using lukewarm water for showers and baths
Avoiding very hot or cold foods and drinks
Limiting time outdoors in extreme weather
Being cautious with exercise in hot, humid environments

Sun protection

If sunlight triggers your hives, practicing sun protection is essential. Use sunscreen with a high sun-protection factor (SPF) and wear protective clothing when outdoors.

What to expect

Acute urticaria is usually benign and self-limited. Most cases resolve on their own within days to weeks.

For chronic urticaria, the outlook is generally good. More than one-half of patients with chronic urticaria will have resolution or improvement of symptoms within one year. However, some people may experience symptoms that persist for months or years before eventually resolving.

Chronic hives can interfere with sleep, work, and other daily activities. However, they are not typically life-threatening unless they occur with throat swelling or other symptoms that restrict breathing.

It's important to remember that while urticaria can be frustrating and uncomfortable, effective treatments are available. Working closely with your doctor, especially an allergist who specializes in treating hives, can help you find the right treatment plan.

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