[Frequency of exercise-induced asthma in a group of children and adolescents with mild asthma attending a summer camp].

Background: Exercise-induced asthma is a transitory bronchospasm, which occurs after 6 to 8 minutes of continuous exercise. Diagnosis is done by a suggestive clinical history and by 15 to 20% post-challenge fall in FEV1. It happens in about 6 to 13% of general population, 90% of asthmatic individuals and 40% of individuals with allergic rhinitis.

Objective: To know the frequency of asthma induced by exercise in a group of asthmatic children and teenagers who went to a summer camp.

Material And Methods: A cross-sectional, descriptive and observational study, which included 33 patients suffering from intermittent mild asthma, was based on espirometric measurements made before and after 8 minutes of continuous exercise (running). None of them had previous diagnosis of exercise-induced asthma. FEV1 greater than or equal to 15% was considered exercise-induced asthma. The test was performed at a room temperature of 73F and humidity of 40%. All patients were asymptomatic before the study and were given short-acting inhaled beta2-agonists as rescue medication, which was not administered during the 12 previous hours to the test. Data analysis was made by means of descriptive statistic.

Results: Thirty-three children aged 8-16 years with diagnosis of asthma were studied, with an average age of 12.5 years; 42.4% were female and 57.5% male. Of the 33 patients, 6 had (18.2%) a 15% fall in FEV1 after exercise; 50% of these patients showed exercise-induced mild asthma, 33% moderate and 17% severe. At the end of the test, in six patients (100%) FEV1 increased by 15%, five minutes after the administration of a beta2-agonist.

Conclusions: Exercise-induced asthma is frequent among asthmatic pediatric patients, occurring in 18.8% of this study. Likelihood of having exercise-induced asthma must be deliberately investigated in all asthmatic patients, in order to establish an opportune diagnosis of this condition and provide recommendations of preventing therapy.