We examined the prevalence of chronic sinusitis among children who presented to allergy clinics with chronic (> or = 3 months) respiratory symptoms. Ninety-one patients, ranging from 2 to 17 years of age with 62% male and 72% white, completed the study. Fifty-nine percent of patients had positive skin test results, and 25.3% had chronic asthma. Paranasal sinuses were examined by coronal sinus computed tomographic scan. Sixty-three percent (58 to 91) had chronic sinusitis, 5.5% (5 of 91) had concha bullosa, 1% (1 of 91) had foreign body, and 19% (19 of 91) had deviated nasal septums. Among symptoms of sneezing, nasal congestion, postnasal drip, coughing, wheezing, rhinorrhea, and headache, no single symptom was an acceptable predictor of abnormality on computed tomographic scan examinations. Combining the symptoms of moderate to severe rhinorrhea and cough with minimum sneezing had a specificity of 95% and a sensitivity of 38% in predicting the presence of chronic sinusitis. Allergic rhinitis (p = 0.27), mild deviated nasal septum (p = 0.11), unobstructive concha bullosa (p = 0.13), and passive exposure to cigarette smoke (p = 0.53) were not risk factors associated with sinus abnormalities. Age (r = 0.30, p = 0.004) in pediatric patients with chronic respiratory symptoms was the single risk factor significantly associated with abnormalities on sinus computed tomographic scan. Seventy-three percent of children 2 to 6 years of age, 74% of children 6 to 10 years of age, and 38% of children older than 10 had chronic sinusitis.(ABSTRACT TRUNCATED AT 250 WORDS)