You’re probably aware that certain foods and medications can cause hives, but you might not know that extreme heat, cold, or even water could lead to symptoms for some people.
When it comes to managing your chronic hives (also called chronic urticaria), it can be difficult to identify the cause. The condition may be classified as idiopathic — meaning the cause is unknown — or it could be prompted by a variety of factors that combine and make hives linger.
Unlike acute hives, a condition that lasts for short periods and tends to be related to exposure to allergens like pollen or specific foods, chronic hives last longer than six weeks and can include recurring episodes and intense rashes.
Chronic hives can be related to common allergens, such as certain medications, foods, or infections, but there are other potential triggers that might be surprising.
"There are some rare conditions with urticaria that may be challenging to diagnose at first, but knowing some of the more surprising and uncommon causes could help to pinpoint what's going on," says Nicole Weiler, MD, a dermatologist and a clinical assistant professor of dermatology at New York University Langone Health in New York City. "The treatment may be the same from that point, but knowing this is helpful in many cases for avoiding triggers that might make hives worse."
Here are six that might prompt symptoms.
1. Autoimmune Conditions
About 1 in 5 people who develop chronic hives also have an autoimmune disease.
A type of hives called autoimmune urticaria can occur when the immune system attacks the body's own tissues, causing frequent release of histamines, a substance that plays a key role in allergic reactions and inflammation. Those with an existing autoimmune disease are more likely to develop this type. Some of those conditions include:
"The most likely autoimmune issue that may lead to chronic hives is thyroid disease,” says Geeta Yadav, MD, a dermatologist and the founder of FACET Dermatology in Toronto. "This association is still rare, but anyone with an autoimmune condition, especially involving the thyroid, should be aware that chronic hives may develop as part of how that condition is affecting the body."
2. Exercise
Called cholinergic urticaria, this condition is related to increased body temperature and sweat, usually prompted by high-intensity exercise, says Dr. Yadav. It's actually fairly common, affecting about 7 percent of people with chronic hives.
Also known as "heat hives," the condition can be triggered by very hot showers, but most often occurs if you spend an extended time with a higher core temperature, as you would with moderate to vigorous physical activity. Other triggers can include:
Anxiety, upset, or anger
Fever
Saunas or hot tubs
Spicy foods
Stress
The reason cholinergic hives occur isn't fully clear, but it may be because the rise in heat leads to the release of acetylcholine, a neurotransmitter in the nervous system that sends signals between neurons and other cells. With cholinergic hives, acetylcholine floods into the nerve endings near the surface of the skin, causing a reaction.
"Another consideration with exercise is that tight clothing, which is sometimes used for exercise, isn't considered a cause of chronic hives, but it can be irritating to skin and make an existing hives rash worse," Yadav says. Her recommendation: Choose sweat-wicking fabrics (so sweat isn't sitting on the skin and causing dryness and irritation) and looser clothing when working out.
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3. Water
Believe it or not, you can actually develop hives from exposure to water. This condition, known as aquagenic urticaria, is extremely rare, says Dr. Weiler. Only about 50 cases have ever been reported.
"With this, people repeatedly develop hives after water exposure," she says. "Hives occur when the skin comes into contact with any form of water, which includes bathing but also sweat, tears, and rain."
The good news is that, although aquagenic urticaria is a chronic condition, symptoms tend to be temporary. Hives usually develop within 30 minutes of exposure, last up to two hours, then usually resolve without any treatment. People with aquagenic urticaria can still drink water, since the liquid doesn't touch the skin, but some may develop symptoms inside the mouth or on the lips.
The exact cause isn't known, but it's possible there's a chemical or allergen in the water that's problematic for those with this condition. Because it's not realistic to avoid water completely — people need to bathe, for instance — treatment usually involves ongoing antihistamines, Weiler says.
4. Sunshine
Exposure to extreme temperatures of heat and cold are a common trigger for hives, but a lesser known environmental factor is sunshine, says Yadav. That might be because it's far less common, making up only about 0.5 percent of all urticaria cases.
Known as solar urticaria, the condition is characterized by recurrent rashes triggered by exposure of the skin to sunlight. Symptoms often begin just a few minutes after sun exposure, but may also occasionally be worsened or prompted by some medications, especially:
atorvastatin
chlorpromazine
tetracycline
oral contraceptives
The root cause of solar urticaria isn't entirely understood, but a prevailing theory is that a hypersensitivity to sunlight kicks off production of a substance in the body called chromophore. When this happens, the substance sets off an immune reaction, as if the skin has been in contact with an allergen.
5. Gastrointestinal Infections
Infections in general can sometimes kick off acute hives because they raise inflammation throughout the body, but difficulties with the gastrointestinal system specifically can contribute to chronic hives, says Weiler.
That's because the way certain gut-related bacteria operate in the body can cause systemic issues, including skin issues. One gastrointestinal infection in particular, called Helicobacter pylori, has a strong association with chronic urticaria, and research suggests that treating that infection directly can sometimes help treat the urticaria along the way.
6. Vibration
Another rare cause of chronic hives is exposure to vibration, which can encompass anything from use of a jackhammer to frequent bumpy bus rides.
"This is one of the most surprising triggers for hives, because you wouldn't connect something like vibration to such a dramatic effect in the body," Yadav says. "This type isn't seen often but it does occur, and when it's difficult to pinpoint a cause, vibration should be considered as a possible factor."
Known as vibratory urticaria, it's likely caused by repetitive stretching of the skin through vibration. In addition to a rash, you may experience:
Headaches
Fatigue
Feelings of faintness
Blurred vision
Metallic taste inside the mouth
Facial flushing and swelling
Reactions tend to occur within a few minutes of the vibration and generally last up to an hour, but you could have several episodes per day if the vibration is ongoing.
This type of hives is often linked to a mutation in a gene called ADGRE2, which provides instructions for making a protein that's found in some immune system cells, including mast cells. That kind of cell is found in many body tissues, including the skin. The gene mutation causes more fragility in how the protein is made, and any type of vibration, friction, or stretching can cause a problem in how mast cells operate, leading to symptoms of chronic hives.
The Takeaway
Some instances of chronic hives are idiopathic, meaning that the cause is unknown, but the most common triggers involve specific foods, allergens, and infections.
In addition to common causes, there can be some lesser known or surprising reasons you're getting hives, including exposure to sunlight, water, exercise, an autoimmune disease, and even vibration on the skin.
Even though treatment may be similar no matter what the cause, it's helpful to know what's prompting your hives so you can avoid those triggers in the future.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Stephen Kimura, MD, is a board-certified allergist and immunologist. He's been in private practice in Pensacola, Florida, for the past 25 years with the Medical Center Clinic, a multi-specialty practice. He enjoys working with people who were seen as patients as children and now are bringing their children to him for care.
Dr. Kimura received his medical degree from the University of Kansas School of Medicine. He went on to complete his residency at Butterworth Hospital in Grand Rapids, Michigan, and later received additional training in allergy and immunology during his fellowship at the University of Kansas.
Kimura grew up in Hawaii, and says he has many happy memories of coming home from school to go surfing, snorkeling, and swimming at the beaches there.
Elizabeth Millard is a freelance writer based in northern Minnesota. She focuses on health, wellness, and fitness, and has written for Runner's World, Bicycling, Self, Women's Health, Men's Health, Prevention, Experience Life, and more. She is an American Council on Exercise–certified personal trainer and a Yoga Alliance-registered yoga teacher. She graduated from Harvard University with a bachelor's degree in English.
