What to do when exercise triggers hives

When someone claims to be allergic to exercise it might sound like a creative excuse to avoid working out. But for some, exercise can trigger a type of itchy skin rash, commonly known as exercise-induced hives (urticaria). It can be alarming to break out in red spots after breaking a sweat. Here’s what to know if it happens to you.

What are exercise hives?

Exercise-induced hives appear as raised itchy spots or blotches that are either red or skin-colored. They can appear anywhere on your body. The American Academy of Family Physicians (AAFP) says symptoms occur when you engage in physical activity and can include:

• Itchy skin
• Flushing (redness) of the skin
• Hives that appear as large or small bumps or raised patches

In severe cases, exercise-induced hives can trigger exercise-induced anaphylaxis (EIA), a potentially life-threatening allergic reaction, but this is very rare. In addition to potentially having hives during EIA, blood pressure can drop, and the lips, tongue, and throat may swell during exercise—which can inhibit breathing. If you experience difficulty breathing, stomach cramping, headache, lightheadedness, swelling of your face, tongue, or hands, or chest tightness, seek emergency medical care. This severe reaction can occur in people who are allergic to certain foods—such as shellfish, wheat, or hazelnuts—and then exercise shortly after eating. Individuals with this condition may not even be aware of the food allergy, because symptoms may only be experienced when the food and exercise occur in close proximity. 

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What causes exercise-induced hives?

“Hives are caused when the mast cells release histamine,” says Tyler Vukmer, DO, a dermatologist in Golden, Colorado, and founder of INKMD. Histamine is a chemical made by your body, typically in response to an allergen, that causes traditional allergic symptoms like stuffiness, sneezing, or itchy eyes. However, your immune system can also release it in response to heat exposure or increased body temperature.

“The list of conditions known to cause hives is extensive, but one trigger is heat that occurs during exercise or a hot shower,” Dr. Vukmer says.

Most people who get exercise-induced hives report breakouts after a vigorous activity such as running, aerobics, dancing, and bicycling—all cardiovascular activities that get your heart rate and your temperature up. 

What should you do if you get hives from exercise?

If you get hives while working out, stop exercising as soon as you notice them. If the hives are accompanied by other symptoms such as swelling of the face, tongue, or hands, and shortness of breath, you should seek immediate medical attention.

But, it’s not healthy or practical for most people to avoid all forms of physical activity. Instead, try these strategies:

• Take allergy medication before exercise: “We focus on treating the symptoms through the use of oral antihistamines,” Dr. Vukmer says. “My go-to antihistamine is fexofenadine 180 mg (generic for Allegra). While this doesn’t always cure the condition, it does improve the symptoms.”
• Use anti-itch topical medication: Apply treatments like Benadryl cream or calamine lotion to the places where hives appear.
• Don’t eat before working out: “Certain foods including celery, shellfish, and wheat have been linked to exercise-induced hives,” says Purvi Parikh, MD, an allergist with the Allergy & Asthma Network. “To prevent this, we recommend exercising on an empty stomach and not eating for three hours before a workout.”
• Avoid triggers: If running gives you hives, but swimming laps does not, modify your workout routine accordingly. Or, if it only happens on hot, humid days try moving your workout indoors to an air-conditioned room when it’s too warm. Experiment with lower-impact routines.
• See an allergist: “Hives that last less than six weeks are considered acute,” Dr. Vukmer says. “If you have hives that last longer than six weeks, those are considered chronic, and I recommend consulting an allergist to discuss treatment options like Xolair.”
• Discuss emergency treatment: If you have a history of anaphylactic reactions, discuss potential treatments with your healthcare provider, such as EpiPens, auto-injectable devices that deliver a dose of the life-saving medication epinephrine, when someone is having a severe allergic reaction.

No one who experiences exercise-induced hives should suffer in silence. Working with your healthcare provider can help you find a treatment plan that works for your life—without sacrificing physical fitness.