Just Wondering: Why Do My Legs Itch When I Run?

While runner’s itch isn’t yet fully understood, health professionals say there are a few theories behind why you may feel the urge to claw your shin, calf, or thigh mid-run. For instance, Jason Machowsky, RD, CSSD, CEP, CSCS, registered dietitian, exercise physiologist, and owner of JM Wellness, says your legs could start to itch at the beginning of a run if you skip your warmup.

The good news? Experiencing itchiness while jogging usually isn’t a sign of anything super serious—and doesn’t tend to linger. Ahead, find out what causes runner’s itch, plus learn tips on how to prevent and treat it.

Symptoms of runner’s itch

Runner’s itch can feel like an itchy, prickly, or burning sensation on your legs, says Susan Massick, MD, board-certified dermatologist at The Ohio State University Wexner Medical Center. “Symptoms may be annoying, but they won’t last long and will resolve on their own in a short period of time.”

Machowsky suggests the itchiness may subside after a few minutes into your run. Some people may feel complete relief when their workout is over, per the Cleveland Clinic.

Causes of runner’s itch

As Machowsky points out, no one knows the true cause of this spontaneous itching sensation. However, getting your heart rate up may have something to do with it: Small blood vessels called capillaries expand as your heart pumps more oxygen-rich blood to your muscles. “If those blood vessels are near nerve endings or nerve fibers, they might gently press against [the nerves],” he says. “That can create a tingly sensation.”

While vasodilation (widening of the blood vessels) appears to be the leading link, Machowsky pushes back because it doesn’t explain why you might only temporarily feel itchy. “Blood vessels stay expanded during your whole run, so [according to this theory] you would feel it the whole time,” he says.

Another theory: You may be allergic to running. We’re kidding of course—but there’s some truth to that. One 2017 article¹ in Exercise and Sport Sciences Reviews suggests aerobic exercise (like running) releases histamine, a chemical that initiates an allergic reaction. Histamine-induced inflammation could irritate the skin on your legs, especially if you’re sensitive to the chemical, Machowsky says. If you begin to feel itchy all over, “that could indicate an exercise or heat-induced allergic reaction,” he says. Some people may experience exercise-induced urticaria, resulting in hives and skin redness. If this happens, definitely see a doctor.

Of course, dry skin can also cause itchiness and general discomfort. “For some, [runner’s itch] can be seasonal, most notably in the fall and winter when the air is cooler and drier,” Dr. Massick says. Itchiness is a classic sign of dry skin—and the salt from sweat can further dry out your skin.

Chafing, either from your skin rubbing up against your clothing or other skin, can also lead to irritation. Similarly, running in clothing that isn’t made with sweat-wicking materials could trap heat and cause a skin rash.

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Who’s at risk of developing itchy skin while running?

Newer runners and even veteran runners who’ve taken substantial time off from the sport are more likely to feel itchy versus consistent runners. That’s because their bodies haven’t yet adapted (or re-adapted) to the demands of physical activity, Machowsky says. Those who have atopic dermatitis (eczema) or chronic dry skin, may also be at heightened risk, Dr. Massick adds.

How to prevent runner's itch

No matter if you’re new to the sport or a seasoned runner, it’s always a good idea to do a warmup before you hit the trail, track, or road. This can help promote light blood flow to your muscles so that when you begin your workout, your capillaries won’t dilate as rapidly and stimulate neighboring nerves. Don’t overdo your first couple of runs. Machowsky recommends gradually ramping up mileage to give your body ample time to adapt. Start slow and pick up your pace as you adjust.

Dr. Massick says it’s also important to moisturize your skin, especially during those cooler months or in dry climates. Cover your legs and other exposed areas if your skin tends to itch in cold weather. If the heat and excessive sweating tend to bring on your runner’s itch, “wear moisture-wicking, loose-fitting, and breathable fabrics to avoid chafing from trapped heat,” she says.

Most importantly, stay hydrated, Dr. Massick and Machowsky say. If you don’t currently drink a lot of water, one 2023 article² in Children suggests that increasing your fluid intake could boost skin hydration.

How to treat runner's itch

Runner’s itch should resolve on its own, however, if you need extra support, there are a few over-the-counter and natural remedies you can try.

• Apply anti-itch cream ($7)
• Take an antihistamine
• Hop in an oatmeal bath to calm itching and inflammation
• Dial back on the intensity of your workouts

“If you continue to experience itching or notice prolonged redness or skin irritation, you should seek guidance from a board-certified dermatologist,” Dr. Massick says.

The bottom line

If your legs begin to itch while you’re running, try not to panic: The surge of blood flow from aerobic exercise can cause the capillaries to expand quickly, which can trigger neighboring nerves to produce a temporary tingly, prickly, itchy, or burning sensation. Dry skin can also cause runner’s itch. Get ahead of itchy skin by wearing sweat-wicking clothing, doing a proper warm-up, and drinking plenty of water.