What Are Hives? Symptoms, Causes, Diagnosis, Treatment, and Prevention

If you’ve never experienced a bout of hives, consider yourself lucky. Roughly 20 percent of people do get hives at some point in their lives, making it a very common ailment. (1) Hives can be a source of physical and mental anguish, especially if they appear frequently and continue happening for months or years.

What’s important to know is that hives can affect anyone. While some people may carry a higher risk for hives, you can get them no matter your age or gender. Here’s what you should know about the common condition, including why you get hives, how to deal with them if you do, and how to prevent them from coming again (or in the first place).

Hives, formally known in the medical community as urticaria, usually appear as red or skin-colored bumps or welts that have defined edges. They can be as small as a pen tip or as large as a dinner plate, and when you press the center of a hive that’s red, it can turn white, something referred to as blanching. (1) They can appear as one hive or show up as blotches or connected patches. And they show up to help control the body’s allergic response to certain triggers.

Hives can be quite itchy, not to mention irritating. While they bring an obvious physical burden, they can hinder emotional well-being too, often isolating individuals socially and affecting performance at work and school, especially if a person has been struggling with hives for a long time, says Sarina Elmariah, MD, PhD, a board-certified dermatologist at Massachusetts General Hospital in Boston.

RELATED: Tips for Better Skin From Experts and Readers Like You!

As you may suspect, hives are easily confused with other conditions, but there are a few characteristics that distinguish them. “Although many conditions can look like hives, they often don’t behave like hives,” says Adam Friedman, MD, professor of dermatology at the George Washington University School of Medicine and Health Sciences in Washington, D.C.

Namely, how long they last and how much they move can help you determine if a rash or skin condition is hives. Common symptoms of hives are: (2)

• Red or skin-colored bumps or welts with clear edges that typically clear up within 24 hours, but may reappear in another spot
• Bumps or welts that show up either alone or clumped together, covering a larger area
• Itchiness around the bumps or welts
• Swelling around the bumps or welts
• Sometimes pain or stinging at the site of the bumps or welts

If hives last for six weeks or longer, you may be dealing with chronic hives, which can be a sign that something else is going on. (For more information about chronic hives, see below.)

Learn More About Signs and Symptoms of Hives

Although hives can have many causes, they all get their start when immune cells in your body called mast cells are activated. In many cases, those mast cells release a chemical called histamine that can cause swelling, itching, and redness. Although not all hives are the result of histamine being released, the vast majority are, Dr. Elmariah says. Here’s the real question, though: What’s causing those mast cells to react in the first place?

That’s a relatively easy question to answer if you have acute hives. “We can generally identify about 50 percent of the triggers after taking a good history of the patient and getting the full story behind the incident,” Dr. Friedman says.

Chronic hives, however, often have different outcomes, and unfortunately, although about 50 percent of hive cases will be resolved within a year of entering the chronic phase, some people will have hives their entire life. “With chronic hives, we can rarely identify why they’re happening, and the longer somebody has hives, the less likely it is that they’ll go away,” says Friedman, adding that 20 percent can continue for longer than 10 years.

Causes for hives are numerous and can be separated by allergic reactions and nonallergic reactions. Hive-inducing allergens include food, medications, insect bites and stings, pollen, animals, touching something you’re allergic to (think latex, for instance), and even allergy shots, according to the American Academy of Dermatology. (3) People who suffer from hives are advised against taking certain medications, such as aspirin or NSAIDs, as these medications can worsen hives. (4)

Nonallergic causes consist of bacterial and viral infections; exercise; stress; pressure on or scratching the skin; chemical contact; exposure to sun, heat, or cold; and autoimmune disorders like thyroid diseases and lupus, especially in the case of chronic hives.

Among that list, though, three are perhaps the most common, and Friedman sums it up in one simple phrase: “Food, drugs, and bugs,” he says.

What Are Hives? And Why Do You Get Hives?

Stress Can Contribute to Hives, Too

Stress can be a factor in hives, but it’s usually not an independent risk factor.

“Stress usually isn’t the direct cause, and primarily affects only individuals who are susceptible to hives,” Friedman says. Both chronic and acute hives can be made worse by stress, especially in people more likely to get hives, such as women and people with autoimmune disorders. (5)

Learn More About How Stress Affects Hives and Vice Versa

The majority of cases of hives will clear up on their own. (6) Individual hives will usually disappear within about 24 hours, and instances of hives should stop disappearing and reappearing within a few weeks.

If hives continue for more than six weeks, they could be chronic or a sign that something else is going on. It’s a good idea to see a doctor if hives continue for this long. (1)

Also see your MD if a single hive lasts longer than 24 hours and is painful, or the welts are causing discomfort. (6)

When you see a physician about hives, expect a physical exam. The doctor may recommend additional blood tests and skin tests to determine if there is an underlying issue or cause of the hives. Some long-lasting hives cases may benefit from a skin biopsy to help determine the cause. If the cause of the hives is known (such as an allergen trigger), you might not require further testing. (7)

Learn More About Diagnosing Hives: At-Home Self-Diagnosis, Tests and Screenings, and Your Doctors

“A hive lesion doesn’t usually last much longer than 24 hours, whereas things like bug bites, which are easily confused with hives, can last several days,” Friedman says. That means you might wake up with a hive one morning — and that one specific hive may be completely gone by the next morning, Friedman says. “And they often appear without any warning.”

Hives also move around, and they don’t necessarily care what body part they inhabit. Even your scalp, soles of your feet, and palms of your hands can get hives. “If you see one moving a lot, that signals a hive,” Friedman says.

RELATED: How to Identify Common Bug Bites and Stings

Acute hives last less than six weeks, while chronic hives last more than six weeks. That doesn’t mean you’re covered in hives every day during these time periods, but it does mean that during these time frames, the hives come and go either erratically or sometimes on a more consistent basis, says Anthony M. Rossi, MD, an assistant attending dermatologist at Memorial Sloan Kettering Cancer Center in New York City.

Fortunately, although they might itch a lot, hives don’t leave any marks on the skin once they disappear, regardless of whether you’ve treated them or not.

Hives are neither contagious nor, in most cases, dangerous. There are, however, a few exceptions that should prompt emergency care.

The first is a condition called angioedema, which involves swelling of the tissue beneath the skin. That can lead to swelling in the tongue, lips, throat, hands, feet, and even the inside of the abdomen. As a result, people could have stomach cramps or worse, difficulty breathing. People with hives can have angioedema, but note that “just because you have hives doesn’t mean you’ll get angioedema,” Dr. Rossi says.

When hives are accompanied by swelling and breathing becomes difficult, seek emergency care right away.

Hives may also be the result of a serious allergic reaction called anaphylaxis, Rossi says. If you experience difficulty breathing; swelling of your lips, tongue, or eyelids; dizziness; abdominal pain; or nausea or vomiting in conjunction with hives, seek help immediately.

How you treat hives depends on how many you’ve had and how long you’ve been suffering. If you have one hive that goes away within 24 hours and you’re not having any breathing issues, you probably don’t need medical attention. Instead, you might take a nonsedating, over-the-counter (OTC) antihistamine like loratadine/pseudoephedrine (Claritin), fexofenadine (Allegra), or cetirizine (Zyrtec)
to ward off a second one from occurring, Friedman says. (If you notice a hive and breathing difficulties, you should head to the emergency room or seek other urgent care, during which medical professionals will most likely inject you with epinephrine, a drug that opens the airways in your lungs.) (8)

If you do get a second hive, taking one of these antihistamines should be your first defense. “It’s more about prevention or active treatment,” Friedman says.

If a single hive lasts for longer than 24 hours or is more painful than itchy, or if hives continue to come and go for six weeks or more, it’s time to visit a dermatologist. You can always start with your general physician to get a referral, but because dermatologists are skilled at dealing with hives, they’re your best bet for recommending the appropriate treatment, Rossi says. Dermatologists can also offer patch testing that can identify potential allergens that may cause hives when they come in contact with your skin.

Medication Options

Antihistamines are the first medications doctors will recommend in treating hives, and there are numerous antihistamines at their disposal, in addition to the OTC ones you may have already tried at home. (9) They may even adjust the dosing of certain antihistamines or recommend that you take more than one at a time.

If, however, your hives continue to be severe, doctors may use steroids like prednisone. There’s another treatment called omalizumab (Xolair), an injectable prescription medication. They can also turn to off-label drugs like cyclosporine (Neoral) and other therapies like narrowband UVB phototherapy, ultraviolet light therapy, and vitamin D supplementation.

RELATED: Everything You Need to Know About the Vitamin D You Get From the Sun and From Supplements

You might also be asked to undergo additional testing if your doctor suspects that you have a food allergy or even an autoimmune disorder. With food allergies that are particularly severe, you may have to carry an EpiPen in case you need an immediate dose of epinephrine.

Other Ways to Get Relief From Hives

No matter the treatment course, avoid the urge to scratch the hives. “You risk breaking the skin and getting an infection,” Friedman says.

One of the best ways to relieve an itch is by using cold therapy (just note that if you get hives from cold exposure, this may not be a great option). Use ice packs, a cool cloth, or a frozen bag of veggies like peas, or take a cool shower. Even better, stick a moisturizer in the fridge to cool it down, which will have a double-whammy effect against that itch, Rossi says.

Learn More About How to Manage Hives (and What to Expect if You Need Treatment)

Parents should know that given the high incidence of hives in kids, it’s likely they’ll see hives on their child at least once. But don’t panic. “Acute urticaria [the type that lasts less than six weeks and may even just be a one-time deal] is more common in the young [than chronic urticaria],” says Meghan Feely, MD, a board-certified dermatologist in private practice in New York City and New Jersey and a clinical instructor in the Mount Sinai Department of Dermatology in New York City.

Numerous triggers and allergens can cause hives in kids, but food in particular is a common one for kids, especially if they’re allergic to milk, eggs, peanuts, wheat, or soy. You may not even know they’re allergic to something until their first hive appears, especially if it’s accompanied by an allergic reaction called anaphylaxis, which requires emergency care.

Fortunately, most hives in kids can be treated at home with over-the-counter medication, and most hives in kids go away without much need to do anything. But if the hives continue, you’ll want to schedule an appointment with your pediatrician, who may request food allergy testing. Just make sure you’re taking good notes about the hive incidents, which will help the doctor treat and manage the issue.

Learn More About When and Why Kids Get Hives

Hives can be prevented to some degree, but only if you know what’s triggering them for you. “If you can identify your trigger, the best prevention strategy is to avoid that particular trigger (or, in some cases, triggers),” Friedman says.

Not sure what your trigger is? After your first hive, write down everything you did, including what you ate and what activities you participated in over the previous 24 hours. If you get another hive, repeat the process and see if you spot any similarities.

Once you’ve identified your trigger, you’ll want to take every precaution to avoid it. But in cases where there is no trigger or a trigger hasn’t been identified, your doctor will work with you to determine how to keep hives from continuing to appear. For some people, taking antihistamines or other medications regularly may be the best course of action. (7)

Hives can be an extremely frustrating condition to deal with, and the longer you have them, the more frustrated you may get. Fortunately, though, with the right treatment, you can get those hives under control.

Have you struggled with hives that come and go for six weeks or more? You’ve got what experts call chronic hives, and they can be exhausting — especially because they can cause changes in your sleep, performance at work or school, and social life. “The impact chronic hives can have on somebody’s quality of life is well studied,” Friedman says.

While many of the triggers are the same as acute hives (ones that completely clear up in six weeks or fewer), chronic hives have several different causes, including autoimmune issues and long-standing infections. In some cases, you might have to undergo extra testing to determine the cause — and unfortunately in many cases, a definitive cause will not be identified. (4)

The good news is that while treatment generally starts in the same manner as for acute hives, doctors do have additional medications and, in some cases, tests they can use to help diagnose and treat chronic hives. You’ll just have to make sure you put patience on your side, as it can often take several years for improvements to happen.

Other potential (but rare) complications of either acute or chronic hives can include:

• Angioedema
• Anaphylaxis (which technically is a complication that can happen in tandem with rather than because of hives, but can be life-threatening)
• Anxiety
• Depression

Learn More About Complications of Hives

About 1 in 5 people will experience hives at some point in their lives. (1) And more than 10 percent of children will experience hives at least once. (6)

About 1 in 20 people will experience chronic hives, which are episodes that last for more than six weeks. (10) About half of people with chronic hives still have them after antihistamine treatment. (7) And for about half of cases, the trigger of chronic hives is unknown. (4) Twenty percent of chronic hives patients suffer for more than five years. (11) Chronic hives are more common among women than men. (12)

Much of the research surrounding hives in the past couple of years has focused on the effectiveness of omalizumab (sold under the brand name Xolair). It’s an anti-immunoglobulin E antibody that was somewhat recently approved as a treatment option and is available by prescription. It’s now recommended to treat chronic hives. (13)

Other studies from the past two years include:

• A 2019 study found that tests intended to diagnose or assess chronic hives rarely shed light on what’s causing the issue, though they significantly increase financial costs. (14)
• A 2018 study explored the diets of people with chronic spontaneous urticaria and how food can exacerbate certain symptoms. The researchers found that food typically is not the trigger for chronic hives, even though many patients think it is. (15)
• Another 2019 study found that autoimmunity and autoallergy antibodies can lead to the development of chronic spontaneous urticaria and predispose people to developing other autoimmune diseases. The researchers also found that patients with the autoallergy antibody seem to respond more quickly to omalizumab than those with autoimmunity issues. (16)
• New treatment options, including infusions, topical treatments, and oral ones, are being explored to treat chronic hives patients who have not responded to current treatments. (11)

Much of the research that’s currently being done regarding hives involves testing whether certain medications are effective treatment options, such as fenebrutinib, AK002, UB-221, ligelizumab, and dupilumab. (17)

Finally, researchers are also exploring how vitamin D levels among hives patients compare with those of others and how vitamin D supplementation affects the severity of hives. (17)

Hives can sometimes be a symptom of or be mistaken for other skin problems. Similarly, certain conditions and other things can trigger hives. The following are related to hives for at least one of these reasons:

• Allergies Acute hives (hives that go away quickly) oftentimes occur as part of an allergic reaction. The trigger could be certain foods, medicines, fabrics, pollen, animals, or insect bites. They can appear anywhere on the body. Sometimes they’ll appear within minutes of exposure to the allergen, and other times they may not appear until hours later. (3)
• Exercise Some people experience hives during physical activity. Exercise-induced hives are oftentimes accompanied by flushed skin, itchiness, and difficulty breathing. (18)
• Psoriasis This common skin condition results in red patches in areas where skin cells build up. The irritated area might look like hives, but one way to tell between them is to look for silvery scales on the skin, which is a feature of psoriasis, but not hives. (19)
• Stress Stress can sometimes manifest itself as hives on the body. (3) If you’ve experienced hives as a result of allergies, you’re more likely to see them pop up during stressful times. (20)
• Cellulitis This potentially serious bacterial infection is marked by red, swollen skin that feels warm and painful. Be careful not to brush off symptoms of cellulitis as hives. Cellulitis can become life threatening if left untreated. Be on the lookout for a fever and a rash that’s spreading quickly. (21)
• Irritated Skin A mild case of hives will look very similar to irritated skin. How can you tell the difference? Track how long the irritation sticks around. Hives usually go away within 24 hours, though new hives may take their place. (22)
• Eczema Eczema, a chronic skin condition that generally begins at infancy, also can be mistaken for hives. A key difference is where the rash appears. Eczema tends to occur on the face, elbows, and knees and may look scaly, whereas hives can occur anywhere on the body. (23)
• Rosacea Rosacea typically appears on the face and looks a lot like acne. The red bumps are different from hives in that they may contain pus, and your skin may feel warm and tender. (24)

More than 50 percent of cases of chronic hives are believed to occur alongside an autoimmune disease. (25) The following autoimmune diseases can trigger chronic hives:

• Type 1 Diabetes Long-lasting chronic hives could be an early indicator of type 1 diabetes. (26)
• Lupus It’s not very likely, but lupus can cause hives, possibly because of the existence of certain antibodies, sunlight, or response to some medications. Hives typically will go away within 24 hours, but if they last longer, it could be a condition called urticarial vasculitis. (27)

Favorite Orgs for Essential Hives Info

American Academy of Allergy, Asthma & Immunology (AAAAI)

Not sure if the rash on your skin is hives or something else? Visit this page from AAAAI to view photos that have been submitted by other hives patients. It’ll help you identify what other hives outbreaks look like.

Mayo Clinic

Visit this site to learn all about the causes, symptoms, diagnosis, and treatment of chronic hives. The site also includes a helpful list of questions to ask your doctor, and which questions he or she will likely ask during your first appointment. You can also connect with Mayo Clinic doctors who treat the condition.

Seattle Children’s

Visit this website if your child seems to be suffering from hives. It’s filled with essential information to help you identify symptoms and what may have caused the outbreak. It also has helpful information about how quickly you need to seek help — whether the symptoms can be treated at home, if you need to call a doctor during office hours, or if the severity warrants a 911 emergency call.

Favorite Tool to Virtually Identify an Allergy

The Virtual Allergist

Sometimes hives can be part of an allergic reaction. This interactive tool from AAAAI can help pinpoint the issue. Just click through a series of questions and mark where on the body the allergy is occurring and the symptoms you’re experiencing, and you’ll be presented with possible issues.

Favorite Online Community for Support

CSU & You

This site brings together people with chronic spontaneous urticaria, which is a term that describes chronic hives with no explanation for what’s causing them. The site has information about the condition, videos from people sharing their experience with hives, and “The Hive,” which allows people to send virtual support for people battling the condition.

Favorite Resource to Find an Allergist

American Academy of Allergy, Asthma & Immunology “Find an Allergist” Tool

Generally, you’ll visit a primary care doctor first, but he or she may recommend you schedule an appointment with an allergist. The AAAAI’s “Find an Allergist” tool can help you find an allergist or immunologist close to where you live.

Favorite Resource to Find a Dermatologist

American Academy of Dermatology “Find a Dermatologist” Tool

Your primary care doctor may recommend that you visit a dermatologist instead of an allergist, depending on your symptoms and suspected triggers. If you don’t currently have a dermatologist, visit this site from the American Academy of Dermatology. The “Find a Dermatologist” tool allows you to search by location or a specific doctor’s name. The results will show dermatologists that meet your search criteria. Click on the name to view more about the doctor, such as where they’re located, what they specialize in, and the qualifications they have.