Ringworm is highly contagious. It spreads easily through direct skin contact, shared objects, contaminated surfaces, and even pets. A person with an active infection remains contagious until about 48 hours after starting antifungal treatment. Without treatment, they can spread it for as long as the rash is present.
How Ringworm Spreads
Despite the name, ringworm has nothing to do with worms. It’s a fungal infection of the skin, and the fungi that cause it thrive in warm, moist environments. There are four main ways it spreads:
- Skin-to-skin contact with an infected person, including sexual contact
- Contact with an infected pet, particularly cats and dogs
- Sharing contaminated objects like towels, bedsheets, combs, and clothing
- Touching contaminated surfaces like locker room floors, gym mats, and shower stalls
You don’t need prolonged contact to pick it up. Walking barefoot in a gym shower or borrowing someone’s towel after a workout is enough. Symptoms typically appear 4 to 14 days after your skin comes in contact with the fungus, so you may not connect the rash to the exposure that caused it.
How Long Spores Survive on Surfaces
One reason ringworm spreads so effectively is that the fungal spores are remarkably durable outside the body. Research on common ringworm species found that spores survived about 12 weeks on a towel. A related species lasted more than 25 weeks. Inside shoes, fungal elements can persist for six months or longer.
This means a contaminated hairbrush sitting in a drawer, a pair of shared wrestling shoes, or bedsheets that haven’t been properly washed can remain a source of infection for months. The fungus doesn’t need a living host to stay viable.
Ringworm From Pets
Cats and dogs are common sources of ringworm in households. In pets, the infection may show up as patchy hair loss, scaly skin, or a crusty rash, but not always. Cats in particular can carry fungal spores on their fur without showing obvious signs of illness. Veterinary experts describe these cats as “dust mops,” meaning they’ve picked up spores from their environment and can transfer them to you even though they aren’t visibly infected themselves.
If your pet develops a rash or unexplained bald patches, avoid direct contact with the affected area and bring them to a vet. Treating the animal is essential to stopping the cycle of reinfection in your home.
When You Stop Being Contagious
An untreated ringworm infection is contagious for as long as the rash is present, which can be weeks. Once you start antifungal treatment (either a topical cream for body ringworm or oral medication for scalp ringworm), you’re generally considered no longer contagious after about 48 hours.
That 48-hour window matters for school, sports, and work. Children with ringworm on the body can typically return to school once they’ve started treatment, as long as the affected area can be covered by clothing. Scalp ringworm is handled more strictly: most schools require children to begin prescription oral antifungal medication and bring a medical note before returning. Close-contact sports and PE activities should be avoided until the infection is under control.
Cleaning Your Home to Stop the Spread
Because spores survive so long on surfaces, cleaning is just as important as treating the infection itself. A few key strategies make a real difference.
For laundry, wash contaminated towels, sheets, and clothing twice through the longest wash cycle with detergent, then dry them completely in a dryer. Don’t overload the machine. The mechanical agitation of the wash cycle is actually the most important factor in removing spores, more so than water temperature alone.
For hard surfaces, most household cleaners labeled as effective against fungi will work, including common products like Clorox, 409, Fantastik, and Simple Green. The key is thorough scrubbing to physically remove debris, followed by at least 10 minutes of contact time with the cleaner. Accelerated hydrogen peroxide products are particularly effective. One important note: chlorhexidine, a common antiseptic, does not kill ringworm and should not be relied on.
Focus your cleaning on high-touch areas: bathroom floors, shower surfaces, doorknobs, and any surfaces the infected person or pet regularly contacts.
Who Is Most at Risk
Anyone can get ringworm, but certain situations increase your odds significantly. Athletes in close-contact sports like wrestling, jiu-jitsu, and football face higher exposure because of skin-to-skin contact and shared equipment. People who use communal showers, pools, or locker rooms are also more vulnerable, especially when walking barefoot.
Warm, humid environments encourage fungal growth, so people who sweat heavily or wear tight, non-breathable clothing are more prone to infection. Having a pet with ringworm in the household is another major risk factor, particularly in homes with multiple cats. Children tend to get ringworm more often than adults, partly because of close play with other children and animals.
Keeping skin clean and dry, avoiding shared personal items like towels and razors, wearing sandals in communal showers, and treating infected pets promptly all reduce your risk substantially.