Ringworm spreads through direct contact with an infected person, animal, object, or (less commonly) contaminated soil. Despite its name, no worm is involved. The rash is caused by fungi that feed on keratin, the protein in your skin, hair, and nails. Once the fungi land on your skin, symptoms typically appear within 4 to 14 days.
Skin-to-Skin Contact With People
The most straightforward way to pick up ringworm is by touching someone who has it. The fungi transfer during any prolonged skin-to-skin contact, including sexual contact. This is why ringworm spreads quickly in settings where people are physically close: wrestling mats, daycare centers, and crowded households. Children are especially prone because they tend to have more skin-to-skin contact during play and sports.
A person with ringworm stays contagious as long as they have untreated patches on their skin. Once they start antifungal treatment, they’re generally no longer contagious after about 48 hours.
Catching It From Pets and Other Animals
Animals are a major source of ringworm, particularly cats and dogs. You can pick up the fungus simply by petting or grooming an infected animal. Cows also carry it and are a common source for farmers and veterinary workers.
Cats deserve special attention here. The fungal species most commonly passed from cats to humans is called Microsporum canis. Infected cats sometimes show obvious signs like patchy fur loss or scaly skin, but not always. Some cats act as “dust mops,” meaning they carry fungal spores on their fur picked up from the environment without being truly infected themselves. These cats look perfectly healthy but can still deposit spores on your skin or furniture. If you’ve developed ringworm and can’t figure out where it came from, a recently adopted cat or a neighborhood stray you’ve been petting is worth considering.
Contaminated Objects and Surfaces
Ringworm fungi don’t need a living host to survive. Spores shed onto towels, bedsheets, clothing, combs, brushes, and sports equipment can remain infectious for weeks or even months. In lab studies, one common ringworm species survived on a towel for about 12 weeks, while another lasted more than 25 weeks. That’s half a year of potential exposure from a single contaminated item sitting in a gym bag or laundry pile.
Shared surfaces are another common route. Locker room floors, shower stalls, gym mats, and pool decks stay warm and damp, which is exactly what these fungi need to thrive. Walking barefoot through a contaminated locker room or sitting on a shared bench is enough to pick up the infection.
Soil Exposure
Certain ringworm fungi live naturally in soil. Picking up an infection this way is uncommon and would require prolonged contact with heavily contaminated dirt, not a brief brush with garden soil. Gardeners who work without gloves for long stretches are the most likely group to be affected through this route.
What Raises Your Risk
Some people are more vulnerable to ringworm than others. Warm, humid climates create ideal conditions for the fungi to grow, so infections are more common in tropical and subtropical regions, and spike during summer months in temperate areas. Moisture on your skin plays a big role too. Sweating heavily during exercise, wearing tight or non-breathable clothing, and staying in damp clothes after a workout all give the fungi a better chance of establishing an infection.
Contact sports like wrestling, judo, and football carry particularly high risk because of the combination of skin-to-skin contact, shared equipment, and sweaty environments. Athletes who don’t shower immediately after practice or who share helmets, knee pads, or uniforms are especially vulnerable. A weakened immune system also makes it easier for the fungi to take hold, whether from illness, medication, or chronic stress.
What the Rash Looks Like
Ringworm on the body produces a distinctive ring-shaped rash. The edges are usually raised, red, and scaly, while the center tends to clear as the patch expands outward. It can be itchy, sometimes intensely so. The rash may appear as a single ring or multiple overlapping rings, and it grows gradually over days to weeks if left untreated. On darker skin tones, the redness may appear more brown or gray, making it harder to spot early.
The appearance varies depending on where it shows up. On the scalp, it often causes patchy hair loss with flaky, scaly skin. Between the toes (athlete’s foot) or in the groin (jock itch), the rash tends to look more like a raw, peeling patch than a clean ring. All of these are caused by the same group of fungi.
How to Reduce Your Exposure
Preventing ringworm comes down to keeping your skin clean and dry, and being careful about what touches it. Wear sandals or flip-flops in locker rooms, public showers, and pool areas. Change your socks and underwear daily, and opt for breathable shoes and fabrics when possible. Don’t share towels, clothing, bedsheets, combs, or brushes with others.
If you play sports, shower immediately after practice or games and keep your gear clean. Don’t share helmets, pads, or uniforms with teammates. If someone on your team has ringworm, avoid direct contact with the affected area until they’ve been on treatment for at least 48 hours.
At home, if a family member or pet is infected, wash contaminated fabrics and surfaces with diluted bleach (a quarter cup per gallon of water) or a strong detergent. Keep your fingernails and toenails trimmed short, since fungi can lodge underneath them. And if you’ve recently brought home a new cat or dog, watch for any skin changes on the animal and on yourself in the weeks that follow.