Asymptomatic dermatophyte carriers in the households of children with tinea capitis.

Objectives: To determine the prevalence of the carrier state in household contacts in children with tinea capitis, the duration of the carrier state, factors associated with carriage, and the proportion of carriers who develop clinical disease.
Design: Cross-sectional, cohort, prevalence study.
Setting: General pediatric clinic serving an indigent, inner-city, African American population.
Patients: Household contacts in children with tinea capitis. Index cases and carriers (no clinical evidence of infection) were identified by culture. Carriers were monitored until the results of their culture became negative, they developed clinical disease, or a 6-month period had elapsed.
Results: Fifty-six index cases and 114 contacts (50 adults and 64 children) were evaluated. Ninety-eight percent of the dermatophytes identified in index cases and 100% in carriers were Trichophyton tonsurans. At the initial visit, 18 (16%) of 114 (95% confidence interval [95% CI], 10-24) of contacts were carriers and 14 (32%) of 44 of the families studied had at least 1 carrier. At the 2-, 4-, and 6-month visits, the carrier state persisted in 7 (41%) of 17 (95% CI, 19-67), 3 (20%) of 15 (95% CI, 4-48), and 2 (13%) of 15 (95% CI, 2-40), respectively. Three of the carriers were lost to follow-up. Of the carriers, 1 (7%) of 15 (95% CI, 0.2-32) developed tinea capitis. Univariate and multivariate analysis showed no association of carrier state to age, sex, comb sharing, or cosleeping. However, cosleeping and comb sharing were common among the contacts, occurring 75% and 78% of the time, respectively, making statistical correlation difficult with our sample size.
Conclusions: Initial prevalence of asymptomatic carriage of dermatophytes among household contacts of a child with tinea capitis was 16%, with 41% of carriers persisting up to 2 months. Thirty-two percent of families had at least 1 member who was a carrier. Seven percent of the carriers developed an active infection. Treatment of carriers with sporicidal shampoo should be considered since they may act as a reservoir for infection or develop active disease. The high prevalence of cosleeping and comb sharing may be important factors in the spread of the disease.