Among asthmatic children who are in clinical remission, measuring the amount of nitric oxide in their breath could help predict how likely they are to relapse, Dutch researchers report.

Exhaled nitric oxide is thought to reflect the degree of inflammation in the airways.

The study is the first to show nitric oxide concentration as a relapse marker in children who are no longer taking inhaled corticosteroids, Dr. J. C. De Jongste of Erasmus Medical Center in Rotterdam and colleagues report in the medical journal Thorax.

Current practice is to stop inhaled steroids after children have been symptom-free for longer than 6 months while on low-dose steroids, the researchers note, but there is currently no way to predict which children will relapse.

To investigate the potential role of exhaled nitric oxide in predicting asthma relapse in children, the researchers studied 40 children with asthma in remission. The researchers measured nitric oxide in the kids’ breath before they stopped taking steroids and 2, 4, 12 and 24 weeks after stopping.

Among the nine patients who eventually experienced a relapse, exhaled nitric oxide levels were higher at 2 and 4 weeks after stopping steroids compared with those who did not relapse, the researchers found.

“Our findings in this relatively small group of asthmatic children strongly suggest that forced exhaled nitric oxide measurements at 2 and 4 weeks after cessation of steroids are helpful for identifying children in whom relapse of asthma is more likely to occur and who might benefit from a close follow-up,” De Jongste and colleagues conclude.

SOURCE: Thorax, March 2005.