Nitric oxide in children with persistent asthma.

OBJECTIVE To assess the difference in exhaled nitric oxide levels in atopic and nonatopic asthmatic patients treated with anti-inflammatory drugs, and to compare exhaled nitric oxide measurement with lung function tests. METHODS Cross-sectional study with 45 consecutively selected patients with moderate and severe persistent asthma, aged between 6 and 17 years, and treated with anti-inflammatory drugs for at least 1 year. The patients were split into two groups: atopic ones (with positive skin tests) and nonatopic ones. The clinical and functional assessments and the measurement of exhaled nitric oxide were carried out concomitantly. RESULTS There was a male predominance (62.5%), with an age range between 6 and 13 years (mean of 10.4 years) in 85% of the patients. Neither the symptoms associated with asthma (p = 0.07), allergic rhinitis (p = 0.17), food allergy (p = 0.09), necessity of systemic corticosteroids (p = 0.10), antileukotrienes (p = 0.20) and antihistamines (p = 0.70), nor the three parameters used to assess lung function (FEV(1), FEV(1)/FVC and FEF(25-75%), p > or = 0.14) were statistically significant. The frequency of eczema (p < 0.005) and exhaled nitric oxide levels (p < 0.001) were higher among atopic patients. CONCLUSION Results suggest that clinical and functional stability of asthma among atopic patients does not necessarily reflect an efficient control over the inflammatory process and a higher probability for recurrence after discontinuation of anti-inflammatory therapy.