You go to the gym to keep yourself healthy, not to get skin infections. 

But researchers are finding that the places where people congregate to get fit can also be breeding grounds for a wide variety of germs.

For example, 25 different categories of bacteria were found on exercise equipment, handrails, and toilet handles at four fitness centers in Memphis, in a December 2014 study published in the International Journal of Environmental Research and Public Health.

The most prevalent species were forms of Staphylococcus bacteria, also known as staph—a common source of skin infections.

Why Skin Infections Crop Up at the Gym

It’s easy to see how coughs, sneezes, and unwashed hands might quickly spread the viruses that cause colds from one treadmill to the next. But, it turns out, the majority of infections people pick up at the gym are actually those that affect the skin.

That’s because the bacteria, fungi, and viruses that cause skin infections thrive in the sweat that gets left on exercise equipment and towels, as well as in warm, moist areas such as saunas, showers, and swimming pool decks.

For example, research shows that methicillin-resistant Staphyloccocus aureus (MRSA)—which causes staph infections difficult to treat because they are resistant to multiple antibiotics—can live for days on exercise machines, mats, and locker-room benches.

“Skin infections, including MRSA, are most commonly reported in athletes engaged in sports that involve skin-to-skin contact, such as football or wrestling, but transmission can also occur not just during sports but also before and after participation—in locker rooms, for example,” says Amber Marie Vasquez, M.D., an Epidemic Intelligence Service Officer in the Prevention and Response Branch at the Centers for Disease Control and Prevention (CDC). “Open wounds, poor hygiene, and the sharing of towels and equipment all increase your risk.”

Types of Infections

The five infections below are among the most common skin problems you can acquire at the gym. Here’s how to spot and treat them.

Athlete's Foot and Jock Itch
These two infections are caused by a group of fungi that grow in warm, moist areas, including damp towels, sweaty workout clothes, and wet floors. The fungi cause a red rash that often itches like crazy. The affected skin may also peel or appear scaly and blister. Men are more prone to jock itch than women. However, women may develop fungal infections under their breasts, and both sexes can get them in their armpits.

Treat it: Wash the affected area with soap and water daily and dry well. An over-the-counter antifungal product containing clotrimazole (Lotrimin AF and generic), miconazole (Micatin and generic), or terbinafine (Lamisil AT) will clear up most infections in a couple of weeks. If symptoms last longer than that, see your doctor; you may need a prescription medication. 

Hot-Tub Rash
The culprit here is the bacterium Psuedomonas aeruginosa, which can be found in swimming pools and hot tubs when levels of disinfectants such as chlorine are too low. (The same bug causes swimmer’s ear, a common infection of the outer ear canal.) Hot tub rash typically starts as itchy spots in the swimsuit area that evolve into a bumpy red rash. You might also develop pus-filled blisters around hair follicles.

Treat it: It typically clears up in a few days without treatment. See your doctor if the rash lingers longer; you may need a prescription antibiotic ointment or pills. 

Impetigo
This highly contagious infection is typically caused by staph or strep bacteria that get into your body through a break in the skin, such as a cut or an insect bite. In some cases, impetigo can also invade healthy skin. The bacteria grow in warm, humid environments and are easily transmitted through skin-to-skin contact with someone who’s infected or through contaminated towels and sports equipment. The infection typically starts out as red, pimplelike sores that fill with pus. After a few days, the sores will break open and form a thick yellow-brown crust. 

Treat it: See your doctor. If you have only a few spots and they’re confined to a small area, five days of treatment with a prescription antibiotic cream will typically clear up the infection. (OTC antibiotic ointments don’t work as well against impetigo.) If the infection is severe or widespread, your doctor is likely to prescribe an oral antibiotic. 

Plantar Warts
These are caused by the human papillomavirus, or HPV, which can infect the skin on the bottom of your foot if you go barefoot in the gym locker room or showers. (The strain of HPV that causes plantar warts is different from the one that causes genital warts.) A tough, calluslike spot may form, and it may be painful to walk on. Tiny black dots may appear on the surface of the wart, a result of dried spots of blood in the blood vessels feeding it.

Treat it: First, try applying an OTC topical product that contains salicylic acid (Compound W, DuoFilm, and generics), keeping in mind that it may take several weeks to see results. If the wart persists, hurts a lot, or bleeds, or if you have many warts, see your doctor; he or she can freeze it off with liquid nitrogen, cut it out, or zap it with a laser. People with diabetes should consult their doctor before treating plantar warts or any other foot problem, because that condition increases the risk of serious foot infections.

Staph Infections and MRSA
The staph bacteria behind these infections are commonly found on the skin or in the nose of healthy people, Vasquez says. Research shows that about one-third of people carry garden-variety staph bacteria and about 2 percent harbor the antibiotic-resistant form, MRSA. These bacteria can infect the skin through cuts or abrasions—even a shaving nick or pimple can provide a place for the germs to take hold. In early stages, a staph or MRSA skin infection looks like a spider or insect bite. The bump may become red, swollen, warm to the touch, painful, and full of pus or other fluid. In some cases, people with one of these infections run a fever.

Treat it: See your doctor. It’s especially important to seek prompt medical attention if you have what looks like a nasty bite and are running a fever. Left untreated, MRSA can develop into sepsis, a life-threatening reaction to severe infection in the body. Some antibiotics will work against MRSA.

Protecting Yourself

Of course, the best form of treatment is prevention. Follow these six strategies to help minimize the risk of picking up a skin infection at your health club:

  • Check the gym’s cleanliness. Ask the management about the facility’s cleaning routine. “Gyms and locker rooms should be cleaned at least daily with detergents or disinfectants registered by the Environmental Protection Agency (EPA),” Vasquez says. When checking out a gym, see whether disinfectant wipes or sprays are readily available so that exercisers can clean shared equipment before and after use. Equipment should also be well-maintained; there should be no damaged surfaces—such as a ripped seat on a workout machine—that make the equipment hard to clean, Vasquez notes. “Also, bathrooms and locker rooms should be stocked with liquid soap or alcohol-based hand sanitizer.”
  • Safeguard your skin. Keep cuts and scraps clean and covered with a bandage until healed. Keep a barrier such as an item of clothing or a towel between your skin and equipment that others use, such as weight-training machines and sauna benches. Always wear flip-flops or shower shoes in wet areas.
  • Bring your own exercise mat. Gym mats, like those used for practicing yoga, may not get cleaned between classes, so it’s safest to tote one with you.
  • Practice good hygiene. Wash your hands before and after playing sports or using shared equipment. If soap and water are not available, the CDC advises using a hand sanitizer that’s at least 60 percent alcohol. Use sprays or wipes to disinfect gym equipment both before and after you use it. Shower after exercising or using a hot tub or swimming pool
  • Do your laundry. Stash sweaty clothes, swimsuits, and used towels in a plastic bag separate from the rest of your gear and wash them after every use. “Evidence shows that the numbers of skin bacteria build up each time we wear a piece of clothing without washing it,” Vasquez says. Heat kills bacteria, so she advises washing and drying items at the warmest temperature level listed on the clothing tag.
  • Be stingy with your stuff. Avoid sharing personal items that touch bare skin, such as razors and towels.

Editor’s Note: Funding for the preparation of this article was provided in part by the Atlantic Philanthropies and by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multistate settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).