Semiquantitative study of tinea capitis and the asymptomatic carrier state in inner-city school children.
OBJECTIVE
To quantify and characterize the asymptomatic carrier state of tinea capitis in school children from the inner city.


METHODS
All students attending a parochial school (kindergarten through seventh grade) in the city of Philadelphia were cultured for tinea capitis periodically over 16 months (1404 hemi-scalp cultures from 224 children).


RESULTS
Our initial prevalence study of this all-black population (ages 5 to 13 years) found a 3% rate of index cases (symptomatic) and a 14% rate of asymptomatic carriers (without black-dot lesions, obvious hair loss, scaling, crusts, pustules, or erythema). Trichophyton tonsurans was the predominant dermatophyte (96% of 125 positive cultures; Microsporum canis was the only other isolate). Fifty percent of all positive cultures came from children in kindergarten and first grade; first grade had the highest rate of index cases. The overall prevalence of asymptomatic carriers was not higher in the classes containing index cases. Fifty-nine percent of asymptomatic carriers had a 1+ spore load (1 to 10 colonies isolated per scalp), while 74% of index cases had a 4+ spore load (> 150 total colonies). Forty-five untreated asymptomatic carriers were followed for 2 to 5 months: 19 (42%) became culture-negative; of these, 17 (90%) had a 1+ spore load.


CONCLUSIONS
We found that inner-city black school children who are asymptomatic carriers of T tonsurans had lower spore loads than index cases. Index cases did not appear to be the primary mode of transmission within a classroom. More than half of untreated asymptomatic carriers remained culture-positive after 2 months and probably play a role in the transmission of tinea capitis within this population.
Williams
J V
JV
Department of Pediatrics, Children's Hospital of Philadelphia, USA.
Honig
P J
PJ
McGinley
K J
KJ
Leyden
J J
JJ
D000293:Adolescent; D044383:Black People; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D002648:Child; D002675:Child, Preschool; D015169:Colony Count, Microbial; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008864:Microsporum / Q000302:isolation & purification; D015143:Philadelphia / Q000453:epidemiology; D015995:Prevalence; D012535:Scalp / Q000382:microbiology; D014006:Tinea Capitis / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D014249:Trichophyton / Q000302:isolation & purification; D014504:Urban Health / Q000706:statistics & numerical data*; D001741:Black or African American