CDC Discovers First Drug-Resistant Ringworm Infections in the US

In a Morbidity and Mortality Weekly Report (MMWR) published by the CDC on May 12, 2023, public health officials identified the first cases of drug-resistant ringworm in the United States. According to the report, these infections were discovered in New York City between December 2021 and March 2023, causing significant public health concerns.

Ringworm, called tinea or dermatophytosis, is a fungal infection caused by dermatophyte molds. According to the CDC, roughly 10 years ago, an antifungal-resistant version of Trichophyton indotineae emerged in South Asia, likely linked to antifungal overuse.

A February 2023 report to public health officials from an NYC dermatologist identified two cases of tinea that did not respond to the standard treatment of oral terbinafine for ringworm. Despite no epidemiological connection, officials are concerned about the potential spread of ringworm in the US.

One of the patients did not report any international travel, implying that drug-resistant versions of ringworm have already been transmitted domestically. Additionally, it indicates to providers that ringworms that do not respond to initial treatments may require closer attention.

According to the CDC, symptoms of ringworm typically appear within two weeks of exposure, including itchy skin, a ring-shaped rash, red or scaly skin, and hair loss. The fungus can be contracted from individual, animal, or environmental exposures.

Standard treatments for ringworm include the following antifungals: clotrimazole, miconazole, terbinafine, and ketoconazole.

Beyond understanding the current state of drug-resistant fungi, the public should consider the following prevention strategies:

• Keeping the skin dry and clean
• Wearing breathable shoes
• Wearing shoes in locker rooms and public showers
• Keeping nails short and clean
• Practicing good hygiene
• Washing hands regularly

Additionally, individuals with pets should monitor their pets for tinea and take them to seek care if they suspect it. If an individual has a pet with tinea, they should wear gloves and long sleeves when handling animals and disinfect spaces the pet frequents.

The CDC is working to monitor, track, and minimize the spread of antifungal-resistant ringworm. Additionally, the organization supports discovering new solutions to address antimicrobial resistance.