The Effect of High-Altitude Therapy on Bronchial Hyperresponsiveness in Atopic Asthmatic Children

Background: Chronic asthma is a common, obstructive lung disease, affecting 300 million people worldwide. In the past 30 years prevalence has increased. Control of asthma is currently achieved with pharmacotherapeutic interventions such as inhaled sympathicomimetics and glucocorticocoids. High altitude climate therapy is an alternative method to pharmacological treatment. In the age before antibiotics, high altitude clinics in Europe were popular treatment destinations for those suffering from a variety of pulmonary disorders. Early 20th century researchers demonstrated appreciable benefits for asthmatics sojourning at high altitude. Despite a storied history, high altitude therapy is not a common therapy for refractory asthma in the modern era. Furthermore, the efficacy and underlying mechanism of high altitude therapy for the treatment of atopic asthma remains equivocal. Method: The focus of this study was to review the contemporary literature (1992-2012) that focused on the efficacy of high altitude therapy for the treatment of bronchial hyperresponsiveness in atopic asthmatic children. An exhaustive search of Medline, CINAHL, and Web Of Knowledge was conducted with keyword “asthma” and “altitude”. Results: In the four studies reviewed, there was a significant decrease in total eosinophil count, no improvement in methacholine provocation challenge, a significant improvement in histamine provocation challenge, a statistically significant decrease in CD4 lymphocyte activation, no change in total serum IgE, and weak evidence for improved lung function (FEV1) in subjects undergoing high altitude therapy. Conclusion: The current literature is thought provoking but lacking in quality, validity, and methodology. Furthermore, small sample sizes yield underpowered outcomes and statistically insignificant results. A large randomized controlled trial, with blinding of group allocation and outcome, is needed to further assess the efficacy of high altitude therapy for the treatment of asthma. Keywords: Asthma, high-altitude, bronchial hyperresponsiveness, bronchial hyperreactivity, airway inflammation