Rash From Exercising the Outer Thighs

If you've developed itchy, red skin from a thigh workout, it might make you want to quit. Most thigh rashes are pretty simple to handle, though. If your rash is very painful or gets worse after a few days, talk to your doctor. Rashes that get worse, even if you take a break from your workouts, might have nothing to do with exercise and could indicate a more serious problem.


Urticaria is just a fancy word for hives, a skin condition that causes itchy, red bumps on the skin. Hives, which are common among people who have allergies, usually go away on their own within a few days and sometimes after only a few hours. If you get hives on your outer thigh during exercise, it's probably due to a combination of heat and trapped sweat. However, exposure to allergens can also cause an outbreak of hives. If you know you have allergies, you may want to consider taking allergy medication, particularly if you exercise outside.

Heat Rash

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Heat rash is sometimes called prickly heat or miliaria. Heat rash can cause itchy, prickly skin sensations or cause no pain at all. It's caused by perspiration trapped under the skin, and severe cases of heat rash can cause infections that might require medical treatment. A heat rash during or after exercise is usually due to "unbreathable" or tight clothing that traps perspiration. The rash is more common during hot summer months among people who exercise outside.

Skin Contact

If you rub your skin enough, as is possible when you exercise, it will begin to get raw and red. If you're overweight, skin folds can rub against one another, causing irritation and trapping sweat. But even if you're at a healthy weight, rubbing of clothing or exercise machines on the skin can also cause rashes. The thighs are particularly vulnerable to this rubbing because they're often in contact with exercise machines and frequently covered by constrictive clothing.

Other Causes

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Other conditions can also cause skin irritation during or after exercise. Localized infections due to bug bites, wounds or medical treatments may cause swollen welts, and more serious skin conditions such as skin cancer and fungal infections may also cause a rash. If symptoms don't go away on their own after a few days, talk to your doctor. She may perform medical tests or gather lifestyle information to determine what's causing the rash.


Breathable clothing that wicks away moisture can reduce your risk of perspiration and heat-related skin rashes. Choose clothing that fits properly; clothing that's too tight can trap sweat and clothing that's too loose can rub uncomfortably on your skin. Talcum powder sprinkled on the affected areas can also help keep your skin dry and clean during exercise, reducing your risk of a rash. If you're prone to skin problems, shower right after exercise and avoid using detergents with perfume in them and applying creams and lotions.