New York City’s clinic has confirmed two severe cases of ringworm that have shown resistance to antifungal treatment. The Centers for Disease Control and Prevention published a case study regarding the two cases, which were reported in different years and different countries. The cases raise concerns about a possible hidden outbreak of drug-resistant dermatitis.
Ringworm is a fungal infection that appears as red, itchy rashes on the skin or under the nails. The two New York cases were initially mistaken for a common type called Trichophyton mentagrophytes, which is often contracted from pets such as cats, dogs, and rabbits. However, genetic analysis revealed that the culprit was a recently discovered species called Trichophyton indotineae.
T. indotineae is a closely related fungus to T. mentagrophytes, but it carries protective mutations in the enzyme targeted by terbinafine, a first-line antifungal medication. The first case was reported in December 2021, where a 28-year-old pregnant woman had a persistent, itchy rash that covered her neck, abdomen, pubic region, and buttocks. After two weeks of oral terbinafine, the medication was discontinued due to being ineffective. The rash eventually cleared after four weeks of treatment with a different antifungal medication. The second case was reported in 2022, where a 47-year-old woman developed a similar rash while visiting family in Bangladesh. She also underwent a four-week course of terbinafine but showed no improvement until she was provided with an alternative treatment that eased her symptoms.
The CDC advises healthcare providers to consider T. indotineae infection in patients with widespread tinea, particularly when eruptions do not improve with first-line topical antifungal agents or oral terbinafine. Health authorities are concerned about the possibility of fungi sharing resistance factors that can be passed on to other species, which could reduce the effectiveness of antifungal medication. While T. indotineae seems to be an inconvenience rather than a catastrophe, authorities must not take the issue lightly. The rise of resistance in fungi could lead to difficulties in finding novel antifungals, which is a significant concern in the medical industry.