Ringworm spreads through direct contact with an infected person, animal, object, or surface. Despite the name, it’s not a worm at all. It’s a fungal infection of the skin caused by organisms called dermatophytes, which feed on keratin, the protein that makes up your outer layer of skin, hair, and nails. Understanding the specific ways it travels from one host to another can help you avoid it.
Direct Skin Contact With an Infected Person
The most straightforward way to pick up ringworm is by touching someone who has it. The fungus transfers from their infected skin to yours, where it can take hold if conditions are right. This includes casual contact like brushing against an active rash, as well as prolonged contact during activities like wrestling or sexual contact. You don’t need a visible wound or broken skin for the fungus to establish itself. It only needs to reach your outer skin layer, where keratin provides its food source.
Symptoms typically appear between 4 and 14 days after your skin contacts the fungus, so you may not connect the rash to the moment of exposure. An infected person remains contagious as long as they have untreated lesions, and stays contagious until about 48 hours after starting antifungal treatment.
Touching an Infected Animal
Animals are one of the most common sources of ringworm, especially for children. Dogs, cats, and rodents frequently carry the fungus, and you can catch it by petting, grooming, or handling an infected animal. The most common species involved in pet transmission is Microsporum canis, which thrives on cats and dogs.
What makes animal transmission tricky is that some cats and dogs carry the fungus without showing any symptoms. They look perfectly healthy but shed fungal spores onto their fur, bedding, and surroundings. If ringworm keeps recurring in your household despite treatment, an asymptomatic pet could be the hidden source.
Livestock like cattle and horses also carry ringworm. Horses tend to develop infections in areas where equipment rubs against their skin, such as under a saddle or bridle. Adults are more likely than children to catch ringworm from horses, simply because they’re the ones handling and riding them. Cattle kept in stalls during winter are particularly prone to infection because they rub against wood and other stall materials that harbor spores.
Contaminated Objects and Surfaces
You don’t have to touch an infected person or animal directly. Ringworm spores survive on objects and surfaces, waiting for the next host. Common culprits include shared towels, bedsheets, clothing, hairbrushes, and sports equipment. The fungus deposits spores on these items, and when you use them, the spores transfer to your skin.
Porous items like fabric, carpet, and scratching posts are especially difficult to decontaminate. Bedding or soft toys that can’t be thoroughly washed should be thrown away if they’ve been heavily exposed. Hard surfaces like floors and countertops can be cleaned with detergent, but they need thorough scrubbing rather than a quick wipe-down. Locker room floors, gym mats, and shared showers are classic transmission surfaces because they’re warm, damp, and contacted by many people with bare skin.
Soil Contact
Certain species of dermatophytes live naturally in soil. These “geophilic” fungi can infect you if contaminated soil contacts your skin, particularly through bare hands or feet during gardening or outdoor activities. Soil-acquired infections tend to trigger a stronger inflammatory reaction than those caught from other people, meaning the rash may be more red, swollen, and uncomfortable. This route of transmission is less common than catching it from a person or animal, but it does happen.
Why Athletes Face Higher Risk
Athletic environments create near-perfect conditions for ringworm to spread. A large study of U.S. high school sports found that 73.6% of all skin infections occurred during wrestling, with football a distant second at 17.9%. The rate of skin infections in wrestling was 28.56 per 100,000 athlete exposures, compared to just 2.32 per 100,000 in football. Ringworm specifically accounted for 28.4% of all skin infections across the sports studied.
Several factors stack the odds against athletes. Heavy sweating creates a moist environment where fungi thrive. Skin-to-skin contact during grappling sports gives the fungus a direct route of transmission. Shared equipment like headgear, which often isn’t cleaned between uses, acts as a shuttle for spores. And walking barefoot in locker rooms exposes feet to contaminated floors. The CDC recommends that athletes shower immediately after every competition and practice. When that’s not possible, using soap-and-water skin wipes has been shown to dramatically reduce infection rates. Many schools now wipe down wrestling mats before and after competitions, and referees perform pre-match skin checks to catch active infections before they spread.
Conditions That Help the Fungus Take Hold
Exposure to the fungus doesn’t guarantee infection. Whether ringworm actually develops depends partly on environmental conditions and your skin’s state at the time. Warm, humid environments favor fungal growth. Hot, sweaty skin that stays damp for extended periods is more vulnerable than cool, dry skin. This is why ringworm is more common in tropical climates and during summer months, and why athletes who sweat heavily in close quarters are prime targets.
Overcrowded living conditions also raise your risk, particularly in hot and humid settings where people share sleeping areas, towels, or clothing. Skin that’s already irritated, scraped, or softened from prolonged moisture gives the fungus an easier foothold. Keeping your skin clean and dry after sweating, changing out of damp clothes promptly, and avoiding shared personal items are the most practical ways to lower your chances of infection after potential exposure.