Surface Tension

Your shoes’ worn soles and dirty laces aren’t the only visible cues of the miles you’ve logged. Your skin shows signs of the good (healthy glow), the bad (chafing), and the ugly (blisters). While skin issues certainly aren’t as devastating as a twisted ankle, hamstring pull, or stress fracture, they have the potential to turn an ordinary run into a miserable experience. “Many skin conditions that trouble runners can be quite annoying,” says five-time marathoner Brian B. Adams, M.D., associate professor of dermatology and director of the Sports Dermatology Clinic at the University of Cincinnati. “They can cause such discomfort that they affect your performance or force you to stop.” Luckily, the problems affecting your epidermis are mostly easy to prevent and treat. Here’s how to be kind to your skin.

Athlete’s Foot

This fungal infection results in dry, scaly, red skin between the toes that can itch or burn. Because fungus thrives in warm, moist environments, summertime is a ripe time for athlete’s foot. “Running in the heat magnifies the sweat production on the soles,” Dr. Adams says.

Prevent it: Wear light, moisture-wicking, synthetic (not cotton) socks, says Stephen Pribut, D.P.M., a sports podiatrist in Washington, D.C. After you run, change out of your soggy socks and shoes and slip into dry after-sport shoes before you go for coffee or run errands. Don’t stash your sweaty pair inside a dark gym bag or your trunk where they can’t air out. You can also sprinkle antifungal powder on your feet before running.

Treat it: Apply an antifungal cream for at least four weeks, even if symptoms appear to be gone in half that time, to make sure the infection is gone, says Dr. Adams. Soothe the itch by soaking your feet for 10 minutes in equal portions lukewarm water and apple-cider vinegar (which has antifungal properties). If the condition persists, see a dermatologist, who may prescribe an oral antifungal.

Blisters

“This is probably the number-one raceday injury,” says Paul Langer, a Minneapolis podiatrist and 26-time marathoner. These fluid-filled bubbles are caused by friction, excessive moisture (sweaty feet, wet weather), or shoes that are too small, too big, or tied too tight.

Prevent it: Buying properly fitted running shoes may sound like a nobrainer, but consider this: “Studies show that fewer than half of people’s running shoes were fit correctly,” Pribut says. Because your feet can expand a halfsize over a day, shop in the late afternoon or evening. If you’ve been on a running hiatus, don’t assume you can jump into your old pair. As you age, your feet flatten and lengthen, so you may need to go up a size. If you get toe blisters, Bruce Williams, an Indiana-based sports podiatrist, suggests “toe socks,” which fit like a glove (rather than like a mitten). Putting Vaseline, sports lube, and bandages over blister-prone spots may also help.

Treat it: “Ignore blisters smaller than five millimeters (the size of a pencil eraser) since they’re usually not painful,” says Gregory G. Papadeas, D.O., a Denver dermatologist. But go ahead and pop doozies, especially if they hurt. With a sterile needle, prick the side of the blister and drain it. Don’t remove the blister roof—cover it with an antibiotic ointment and moleskin or a bandage. If you feel a hot spot midrun, address possible causes: Are your socks bunching up? Is your heel slipping? Are your laces too tight? “If the blister hurts so badly that you’re forced to change your gait, you’re better off walking versus risking injury,” Pribut says.

Chafing

Skin-to-skin and skin-to-clothing rubbing can cause a red, raw rash that can bleed, sting, and make you yelp during your postrun shower. Moisture and salt on the body make it worse. Underarms, inner thighs, along the bra line (women), and nipples (men) are vulnerable spots.

Prevent it: Wear moisture-wicking, seamless, tagless gear. Fit is important—a baggy shirt has excess material that can cause irritation; a too-snug sports bra can dig into skin. Apply Vaseline, sports lube, Band-Aids, or NipGuards before you run. And moisturize after you shower. “Drier skin tends to chafe more,” Papadeas says.

Treat it: Wash the area with soap and water, apply an antibacterial ointment, and cover with a bandage. If you’re wearing sports lube and quality clothing and are still experiencing redness, visit a dermatologist. Dr. Adams says it’s very common to mistake a fungal infection for chafing.

Runner’s Toes

During flip-flop season, it’s easy to pick out distance runners. Many marathoners and ultrarunners have discolored toenails, since the more miles you log, the more likely you are to bruise your nails. Lots of downhill running and too-small shoes can exacerbate the issue—both cause your toes to slam into the front of your shoe. Biomechanics are a factor, too. “Some runners pull their toes up while running,” Williams says. “If the toes are chronically lifted against the upper toebox of the shoe, it can cause toenail irritation.” Also, Williams says an unstable big-toe joint can make the other four toes grip too hard (and bruise) upon landing.

Prevent it: Wear properly fitted shoes and trim nails regularly. “Long nails get injured more easily,” Williams says.

Treat it: A bruised nail usually heals on its own within six months. If it’s really painful, see a podiatrist who can drain fluid from under the nail. Also, if it’s a chronic problem, a sports podiatrist could help you determine if toe-lifting and toegripping are to blame, in which case an orthotic may be a fix.

Sunburn

Not only can the sun’s rays cause redness, pain, swelling, and lasting damage, studies show that athletes who train outdoors (unsurprisingly) may have a higher risk of developing skin cancer.

Prevent it: Avoid the sun between 10 a.m. and 4 p.m., wear a hat, run in the shade, and wear sunscreen. Because sunscreen can’t withstand prolonged exercise, stash some in your pocket or circle back to your car so you can reapply every hour, Dr. Adams says. You can also wear technical apparel that blocks UV rays. If not, wear darker colors, which block more UV rays than light colors, and wash clothing with detergent (like SunGuard) that protects against damaging rays for up to 20 washings.

Treat it: Taking an anti-inflammatory and applying aloe vera a few times a day will take the edge off the pain.

Feel Better

Opt for thin socks over thick ones in the summer. Socks with extra cushioning are comfy, but they trap moisture, leading to blisters and athlete’s foot.