The Centers for Disease Control and Prevention (CDC) US reported the existence of two cases of a “supermycosis”. Tinea is a common and highly contagious superficial infection of the skin, hair, or nails caused by Mushroom dermatophytes.
Over the past decade, South Asia has experienced an epidemic of severe tinea resistant to antifungal drugs, drugs used for this type of treatment, due to the rapid spread of Trichophyton indotineae, a new species of dermatophyte. Infections are characterized by inflamed plaques on the skin and also cause general itching throughout the body.
Experts also warn that Trichophyton indotineae isolates are often resistant terbinafine, one of the cornerstones of tinea treatment. Infections from this new species of fungus have been reported throughout Asia, Europe and Canada, but have not been described in the United States. The first two reported cases are now in patients who were diagnosed between December 2021 and March this year.
Fungal infections are characterized by inflamed plaques on the skin and also cause general itching throughout the body. Photo: Freepik
How the cases were discovered
On February 28, 2023, a dermatologist came out new York informed the health authorities about the two patients, who had no epidemiological link to each other and suffered from severe tinea that did not improve with oral treatment with terbinafineraising concerns about possible infection by Trichophyton indotineae.
Skin culture isolates from each were previously identified as Trichophyton mentagrophytes by a clinical laboratory and then forwarded to the New York City Department of Health’s Wadsworth Center for further review and analysis. In March of this year, they identified the isolates as Trichophyton indotineae, the CDC reported.
The first patient is a 28yearold woman who developed a lesion that caused general itching in the North American summer of 2021. Her first dermatological exam was done the same year when she was in her third trimester pregnancy.
“She had no other medical conditions, no known contact with anyone with a similar rash, and no recent international travel,” the CDC said.
Large, ringshaped, scaly, itchy plaques were observed on the neck, abdomen, pubic area, and buttocks. She was diagnosed with tinea and began oral therapy with terbinafine in January 2022, after the birth of her baby.
“Since her rashes did not improve after two weeks of therapy, terbinafine was discontinued and she started treatment with itraconazole. The rash completely disappeared after four weeks of treatment with the drug. However, with the recent confirmation, she will be monitored for a possible recurrence of the infection and the need to restart treatment.”
The second patient is also female. The 47yearold woman, who had no serious health problems, sustained the same injury while in Bangladesh in the summer of 2022. In the South Asian country, she was treated with topical antifungals and creams combined with steroids. She noticed other family members had similar rashes.
After returning to the United States, she visited an emergency room three times in the fall of 2022.
“A 2.5% hydrocortisone and diphenhydramine ointment was prescribed (Visit 1), clotrimazole cream (Visit 2), and terbinafine cream (Visit 3) with no improvement. In December 2022, it was examined by dermatologists who observed disseminated, discrete, scaly, and itchy ringshaped plaques on the thighs and buttocks,” the CDC said.
She was then recommended four weeks of oral terbinafine, but her symptoms did not improve. She then received a fourweek course of griseofulvin, which resulted in an improvement of about 80%.
“Given the recent confirmation of T. indotineae infection, itraconazole therapy is being considered pending further evaluation,” the agency said. The patient’s son and husband, who have traveled with her and report similar injuries, are being evaluated.
With no experience of international travel, the first case catches the attention of authorities because it suggests “potential local transmission” of the new species of fungus across the United States.
The US authorities are on high alert
Therefore, the CDC further advises that healthcare professionals should consider T. indotineae infection in patients with disseminated tinea, particularly when rashes do not improve with firstline topical antifungal drugs or oral terbinafine.
Because the culturebased identification techniques used by most clinical laboratories often misidentify T. indotineae as other types of skin fungi, correct identification requires genome sequencing, according to health officials.
“Public health surveillance efforts and increased testing can help detect and monitor the spread of T. indotineae,” the CDC believes.