Causes and Risk Factors of Ringworm

Ringworm has nothing to do with actual worms. Rather, the red, ring-shaped rash, clinically known as tinea, is a fungal infection. It's highly contagious and spreads easily. Often, all you have to do to catch ringworm is to touch someone or something that may have been infected. Sometimes you can even get a fungal infection by touching the soil.

ringworm causes and risk factors
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Common Causes

There are more than 40 species of fungi that can cause ringworm, according to the Centers for Disease Control and Prevention (CDC). These fungi are known as dermatophytes. Specific dermatophytes associated with the various types of ringworm, including athlete's foot, jock itch, tinea capitis (a fungal infection of the scalp), and others include Trichophyton, Microsporum, and Epidermophyton.

Dermatophytes thrive in warm, moist areas of the body where they feed on dead keratin, skin cells on the epidermis and in nails and hair.

The infections they cause are highly contagious and can easily be transmitted by skin-to-skin contact—that is, by touching someone who has a fungal infection.

Ringworm can infect animals as well, and so when an infected pet—especially a new puppy or kitten—joins a household the human family members are at risk. If you adopt a pet, it's vital to have it thoroughly examined by a veterinarian, but do look for signs of ringworm yourself: circular areas where there's no fur or where the coat is brittle or has broken hairs and the skin is scaly, red, or crusty.

Dermatophyte fungi can thrive on inanimate surfaces as well. They produce spores that are shed into the infected child's clothing, brushes or combs, and even into the air around the child. These spores can survive for months on objects. 

This means, for example, that it's possible to become infected by borrowing a hairbrush or a cap from someone with tinea capitis (ringworm of the scalp) or by going barefoot in an areas where someone with athlete's foot has been walking or standing, such as in a shower stall or gym locker room.

Children are especially susceptible to ringworm and other skin rashes. People born with weak immune systems or who have compromised immune systems due to illness such as HIV/AIDs or certain medications, including corticosteroids or chemotherapy drugs, also have an increased risk of fungal infections.

Lifestyle Risk Factors

Health habits and other behaviors can put you at an increased risk of developing ringworm and other fungal infections. These include:

  • Not washing your hands frequently when around someone or something that might have been exposed to a fungus
  • Having damp skin for extended periods of time—for instance, not showering and drying off completely after sweating a lot
  • Minor skin and nail injuries
  • Close contact with others who have ringworm, such as sharing a room or spending time in a classroom with someone who's infected.

Frequently Asked Questions

  • Does poor hygiene increase the risk of ringworm?

    It can. The Centers for Disease Control and Prevention recommends certain personal self-care measures to avoid getting ringworm:

    • After sweating a lot, shower or bathe and dry off thoroughly.
    • When practical, wear shoes that expose your feet to fresh air.
    • Keep your nails clean and trimmed.
    • Put on fresh socks and underwear every day.
  • What does ringworm look like when it first shows up?

    This depends on where on the body the fungus takes hold, but typically the earliest symptoms of ringworm are itching, a rash that can be red and scaly or form a ring shape, and, if the infection is on the head or beard, hair loss. It can take as long as a couple of weeks for symptoms to appear after exposure.

  • What's the fastest way to get rid of ringworm?

    Using an anti-fungal medication is the quickest way to clear up a ringworm infection. You can make your treatment most effective by:

    • Continuing to use the medication for as long as your doctor advises, even if the rash clears up quickly
    • Washing your hands thoroughly after applying medication—before you touch any other part of your body
    • Keeping the affected area clean and dry
    • If you have multiple areas of infection, treating all of them at the same time
    • Washing towels, bedding, and clothing that may have been exposed to ringworm in hot, soapy water
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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. People at Risk for Ringworm | Ringworm | Types of Diseases | Fungal Diseases | CDC. Aug 6, 2018.

  2. Nenoff P, Handrick W, Krüger C, et al. [Dermatomycoses due to pets and farm animals : neglected infections?]. Hautarzt. 2012;63(11):848-58. doi:10.1007/s00105-012-2379-y

  3. J. Dvořák, Z. Hubálek, M. Otčenášek. Survival of Dermatophytes in Human Skin Scales. JAMA Otolaryngol Head Neck Surg. 2015;141(5):428. doi:10.1001/archderm.1968.01610170100021

  4. Toukabri N, Dhieb C, El euch D, Rouissi M, Mokni M, Sadfi-zouaoui N. Prevalence, Etiology, and Risk Factors of Tinea Pedis and Tinea Unguium in Tunisia. Can J Infect Dis Med Microbiol. 2017;2017:6835725. doi:10.1155/2017/6835725

  5. Centers for Disease Control and Prevention. Ringworm risk & prevention. Updated Jan 14, 2021.

  6. Centers for Disease Control and Prevention. Symptoms of ringworm infections. Updated Jan 14, 2021.

  7. American Academy of Dermatology. Ringworm: 12 tips for getting the best results from treatment.

Additional Reading