MAUI, HAWAII — The largest known U.S. outbreak of tinea capitis due to Trichophyton soudanense and T. violaceum in several decades raises the possibility that the epidemiology of this common fungal disease may once again be on the move.
The cluster of cases is occurring in Baltimore, largely in zip codes that have seen an influx of immigrants from African countries where T. violaceum and T. soudanense are common causes of tinea capitis, Dr. Bernard A. Cohen said at the annual Hawaii dermatology seminar sponsored by Skin Disease Education Foundation.
During 2000–2002, these two organisms accounted for just 0.13% of all dermatophytes isolated by the Johns Hopkins Hospital mycology laboratory. However, the case count rose such that T. soudanense and T. violaceum accounted for nearly 4% of dermatophytes isolated by the lab during the first half of 2006. T. soudanense was second, albeit a distant second, only to T. tonsurans among dermatophytes isolated from the hair and scalp, according to Dr. Cohen, director of pediatric dermatology at the Johns Hopkins Children's Center, Baltimore.
“This persists in our community today. It just shows that these organisms can travel anywhere around the world. This may be a public health issue, not just in our community but in your community as well,” he said.
In contrast to the treatment failure rate reported in U.S. patients with tinea capitis caused by T. tonsurans, all of the Baltimore children with tinea capitis due to T. soudanense or T. violaceum for whom follow-up information was available were cured with 6–8 weeks of griseofulvin treatment at doses of 10–20 mg/kg per day.
Fourteen patients were from East or West Africa. Eleven had been in the United States for 2 years or less.
Dr. Cohen noted that the epidemiology of tinea capitis in the United States has undergone major shifts in the last century. In the late 1800s, and first half of the 20th century, the predominant species causing the infection was Microsporum audouinii. Today in Baltimore, T. tonsurans is the cause of roughly 98% of cases of tinea capitis in African American school-age children.
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These organisms can travel anywhere around the world and can create a public health issue in any community. DR. COHEN