Why do my legs always get hot and start itching when I run or walk fast?

This is more common than you might think. The first thing to check is your clothing detergent or any new soaps that you use. A new detergent or soap that you're not used to might cause an allergic-type reaction on your skin, and you should change it. It's most likely not the case since you've had the problem for such a long time.

What's more likely is that you may be having an allergic reaction during exercise. During exercise, histamines are released and some people are sensitive to them. People sensitive to histamines can experience rashes, itching, and other allergic symptoms during exercise, just like you are describing. Most of the time the rashes appear on the chest and thighs, but can be on the arms or neck too.

Sometimes exercise also reacts with food allergies or medications (e.g., antibiotics, pain medications, sedatives, tranquilizers, and diuretics) to cause the problem.

If the problem is bothering you so much that you can't stand it, and it's not going away, then you should ask your doctor about using a topical ointment to stop the itching, or taking an over-the-counter anti-histamine (like Benadryl) 30-60 minutes before exercising. If over-the-counter anti-histamines make you sleepy, your doctor can prescribe a non-sedative anti-histamine.

You should only take over-the-counter or prescription medication for this problem after speaking with your doctor.

This answer should not be considered medical advice...This answer should not be considered medical advice and should not take the place of a doctor’s visit. Please see the bottom of the page for more information or visit our Terms and Conditions.