The predictive value of symptoms in diagnosing childhood tinea capitis.

OBJECTIVE To determine which sign, symptom, or combination thereof best predicts cultures positive for fungi in children with possible tinea capitis. DESIGN Convenience survey. SETTING Urban hospital-based general pediatric practice. PATIENTS Results were obtained on 100 consecutive children presenting with at least 1 sign or symptom (scalp pruritus, scaling, diffuse or circumscribed alopecia, or occipital adenopathy). INTERVENTION All enrolled children had samples for scalp cultures taken. Demographic information and clinical findings were verified by the author. MAIN OUTCOME MEASURE Whether detected clinical findings can predict the outcome of fungal cultures. RESULTS Cultures positive for fungi were found in 68 children. There was a significant relationship (Fisher exact test; P<.001) between the number of signs and symptoms and a culture positive for fungi. Positive likelihood ratios were 7.5, 3.3, 1.4, and 1.1 for the presence of adenopathy, alopecia, pruritus, and scaling, respectively, for children with cultures positive for fungi. All children (n = 55) who presented with both adenopathy and alopecia and 60 of 62 children who presented with both adenopathy and scaling had cultures positive for fungi. No cultures positive for fungi were found in children without adenopathy and scaling; only 1 of 68 children without adenopathy and alopecia had a culture positive for fungi. CONCLUSIONS In children who are suspected of having tinea capitis, there is a high likelihood of cultures positive for fungi in those with adenopathy. A fungal infection is rarely the cause when neither adenopathy nor alopecia is present. Attention to signs and symptoms in children with suspected tinea capitis can result in better diagnostic and treatment precision.