The purpose of this study is to determine whether parameters of the pulmonary function tests and the bronchial hyperresponsiveness to methacholine are predictors of asthma exacerbations.

Preliminary investigations from our own research group showed that lung function parameters (FEV1, the FEV1/FVC ratio and a moderate to severe hyperresponsiveness to methacholine challenge were risk factors of asthma exacerbations (OR 11.3). In the present study, these parameters will be evaluated in prospective design.

One hundred children will be included in the study. Baseline parameters will be collected in a healthy interval (visit 1), then the children will be followed up for 1 year. If the patients fulfill the criteria for an exacerbation the children will present in our department. We expect that 44% of the children have an exacerbation. All children will present at a second visit after one year (visit 2).

Inclusion Criteria:

• Informed consent
• Age >3 and <7 years
• Diagnosis of intermittent asthma
• In the last 24 months, at least 6 weeks of treatment with a controller medication (inhaled steroid and / or leukotriene receptor antagonist Singulair ®), or in the last 12 months, at least three episodes with an use of controller medications (inhaled steroid and / or the leukotriene receptor antagonist Singulair ®)
• The ability to perform three reproducible spirometries
• Examination in infection-free interval (> 4 weeks infection-free)
• Minimum distance to the following asthma medications:
• Short-acting beta 2-agonists: 8 hours
• Ipratropium bromide: 24 hours
• Long-acting beta 2-agonists: 24 hours
• steroids: 4 weeks
• leukotriene antagonist: 4 weeks

Exclusion Criteria:

• Age older than 6 years or younger than 4
• The inability to perform spirometry
• Other chronic diseases or infections (eg. HIV, tuberculosis, malignancy)
• Participation in another study

Outpatients of departement of Pediatric Pulmonology and Allergology.