The sweat we've all been sweating this hot, hot summer has been bad enough, but throw in heat hives and you might be looking forward to winter's chill. Here's the lowdown of what heat hives are and how to treat and prevent them.
So, what are heat hives?
Heat hives are red, itchy, burning bumps caused by an allergic reaction to the heat or stress, according to Hives.org. Heat hives, also referred to as cholinergic urticaria, occurs in people who are hypersensitive or extremely sensitive to heat or sweat. People with this condition often wonder why they itch when they exercise, or any time they seem to get hot.
Toronto dermatologist Dr. Afsaneh Alavi says that someone can also experience summer hives, also known as solar urticaria. Summer hives are related to sun exposure and result in red, itchy plaques or elevations on the skin. However, the doctor notes that there is another condition that is much more common than summer hives — Polymorphous Light Eruption, which most people experience a few hours after being out in the sun.
"The difference is Polymorphous Light Eruption usually lasts many days after the exposure," says Dr. Alavi. "Summer hives tend to only last a few hours."
And healthcentral.com says that heat hives are different than 'prickly heat,' or heat rash. Prickly heat results from blocked sweat glands that cause a rash with small red raised spots — usually on parts of the body that are covered by clothes. Prickly heat can also cause stinging or itchiness.
Who gets heat hives?
Heat hives can happen at any age, but the majority of cases develop during the teenage years throughout the early 20s, says Alavi. According to Hives.org, here is no difference in prevalence between men and women, races or geographic location. About 15 per cent of people suffer from chronic hives and/or heat hives, which can come and go often, or simply happen once and never again.
Dr. Alavi says females are more likely to develop summer hives, as well as those aged 35 and younger.
What causes them?
Nerve fibres in your sweat glands react to the heat and sweat when your body temperature goes up. Like any allergy, once exposed to the allergen, your immune system releases histamines, causing an itchy or burning sensation on the skin. Hives from heat can also spread beyond the area initially affected.
Activities that raise your body temperature can prompt these rashes and intense burning sensation such as sun bathing, exercising, taking a hot shower, stress, hot climates, tight, clingy clothing or bandages.
You may be more likely to get these hives if you have eczema, asthma, or other allergies such as hay fever, or if you get hives for other reasons, such as a certain food, pressure on your skin, or cold weather.
What do hives feel like?
Red, burning, itchy skin irritation is the most common symptom of heat hives according to Hives.org. Heat hives are itchy, tingly, and warm. They're usually small red bumps with flares or appear as raised welts or bumps with circles around them called wheals.
Hives can break out anywhere on your body, but usually they show up on your chest, face, upper back, and arms. Often, the bumps are close together. Your skin can look swollen and blotchy, or you may just look flushed.
Heat hives often pop up suddenly and can last about 30 minutes to an hour before they fade away.
According to WebMD, more severe symptoms such as headaches, diarrhea, wheezing or shortness of breath, cramps, extra saliva in your mouth, lightheadedness, low blood pressure, rapid heartbeat and other physical side effects can also accompany the rash.
Can you treat them at home?
Over-the-counter antihistamines can be used to reduce an allergic reaction. Ask your doctor or pharmacist for advice about which to try. Antihistamine creams work well and will control the itch, says Dr. Alavi.
If home remedies aren't helpful, talk to your doctor about a prescription antihistamine, steroid, or corticosteroid. These medicines are sometimes prescribed for occasional flare ups of heat hives, severe allergic reactions, hives that don't improve when you cool your body temperature, or to suppress the immune system and prevent hives.
You might think anti-inflammatory medications like ibuprofen would soothe your hives. But these medications actually worsen the reaction, so resist the urge to take them if you break out in hives.
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How can you avoid them?
If you notice heat hives appear during certain activities or in stressful environments, try to avoid these situations when possible. If you enjoy being out in the sun or exercising, come prepared with a cool towel or hive medication in case an episode strikes. Tight clothing plus heat can be a breeding ground for heat hives. When heading into a warm environment, wear loose clothing to prevent your body temperature from spiking.
Avoiding triggers is usually the best approach so people looking to avoid triggers for cholinergic urticaria should avoid over-heating during exercise, spicy food, very hot showers and baths and prolonged exposure to heat.
People looking for lifestyle management should look for ways to reduce and manage their stress and anger, such as through meditation or journaling.
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