African-American children are at increased risk of a relatively new form of ringworm of the scalp, which is more difficult to treat than a previous type that caused epidemics among white children in the 1940s and 1950s, a Washington expert warns.
Currently about 90 percent of those infected with this form of ringworm -- called Trichophyton tonsurans (T. tonsurans) -- are African-American, according to Dr. Rebat M. Halder, chairman of the department of dermatology at Howard University College of Medicine.
Doctors speculate that the resurgence of ringworm may be more widespread than once realized, because of the difficulty in diagnosing and treating the fungus. The diagnosis may be missed in 20 percent of black children, Dr. Halder said.
"The ringworm we saw many years ago which primarily affected Caucasian children could be diagnosed very easily in the doctor's office with a fluorescent light shone on the scalp," he explained. "With this new type, you can't use this light to diagnose it."
It is not known why this type of ringworm primarily affects African-Americans, but doctors suspect genetic factors and/or certain hair-care practices may play a role, Dr. Halder said. Tight braiding may expose the scalp to the fungus, and hair greases can act like a glue that sticks the fungus to the scalp, he said. "That, in addition to the tight braiding, leaves the scalp exposed and unprotected."
While the infection is most common in African-Americans, it is not exclusive to this population, according to a New York pediatric dermatologist.
"It still predominantly affects African-American children, but I'm seeing more Caucasians and Asians with it," said Dr. Seth Orlow, director of pediatric dermatology at New York University Medical Center.
Dr. Halder said the increase in this ringworm type has been noticed over the past two to three years at his clinic, adding that other doctors in urban centers across the country have found the same thing.
Symptoms of T. tonsurans can be subtle, and can persist for months to years without being diagnosed, Dr. Halder said. Some symptoms that may indicate an infection are itching of the scalp, slight scaling and a mild degree of hair loss, he said.
One hallmark characteristic of T. tonsurans is the presence of black dots on the scalp, which are caused by broken-off hairs. "That's because the fungus affects the hair inside the shaft," causing it to break off, Dr. Halder explained.
In the most advanced cases, pus-filled blisters form on the head that can lead to permanent hair loss and severe scarring.
T. tonsurans cannot be treated with skin creams, because the organism grows inside the hair shaft, said Dr. Halder, adding that the treatment of choice is an oral antifungal drug called griseofulvin.
Dr. Orlow said treatment must last six to eight weeks to eradicate the infection.
This type of ringworm is highly contagious, Dr. Halder warned. While children ages 3 to 9 are most susceptible, it also can be spread to adult family members.
To prevent its spread, Dr. Halder recommends that family members not share various hair-care items such as combs, brushes, towels or barrettes.