April 19, 2010 -- Many children attending elementary schools are infected with a fungus that is the leading cause of ringworm in the U.S., a new study shows.
The finding comes from a study of 10,514 children in kindergarten through fifth grade in 44 schools in the Kansas City metropolitan area.
Researchers found that almost 7% of children were infected on their scalps with Trichophyton tonsurans, a fungus that is the leading cause of ringworm in the U.S.
Researchers say the study, the largest of its kind aimed at defining infection prevalence of kids in metro areas, has implications for children across the country.
"The organism T. tonsurans has become the leading cause of scalp infection in the U.S., and we believe it is on the rise in inner city areas," Susan Abdel-Rahman, PharmD, of Children's Mercy Hospitals and Clinics in Kansas City, says in a news release. "This study supports what I and many of my peers are seeing -- children with scaly, itchy scalps and hair loss are prevalent in metropolitan areas."
When not treated, ringworm can lead to permanent hair loss, which can damage a child's self-image, she says. "There is also some evidence that it may worsen seemingly unrelated problems, such as asthma and allergic rhinitis."
Ringworm is caused by a fungus, not by a worm. In the past, the main cause of ringworm was caused by a species of fungus called microsporum that often passed to humans from cats and dogs, Abdel-Rahman says. But Trichophyton tonsurans has emerged in recent years, and it spreads directly between humans. It also is more difficult to find and treat.
Infection rates in this study varied considerably based on race and age. African-American children were found to be at greatest risk.
The study found that:
Infection rates at participating schools ranged from 0% to 19.4%.
Infection rates were greater than 30% in some grade levels in some schools.
More than 18% of the youngest African-American kids evaluated, in first grade or kindergarten, were infected.
By fifth grade, the African-American infection rate had dropped to 7%.
Overall, infection prevalence rates for African-American kids were 12.9%, compared to 1.6% in Hispanic kids and 1.1% in white children