High-altitude treatment: a therapeutic option for patients with severe, refractory asthma?

High-altitude treatment has been applied for more than a century in the treatment of pulmonary diseases including asthma. Many uncontrolled and controlled studies have shown its beneficial effects in children and adolescents with house dust mite allergic asthma. A recent study also showed an improvement in markers of airway inflammation in adult patients with severe intrinsic asthma, suggesting that factors other than HDM avoidance may contribute to the beneficial influence of the high-altitude climate therapy on asthma. The dry mountain climate not only has decreased levels of mite allergens but also decreased levels of pollens, fungal spores and air pollution, as well as high exposure to UV light with immunomodulatory and anti-inflammatory effects. Treatments targeting environmental control have never been investigated systematically in severe asthma, which is surprising, as environmental factors have been recognized as important contributors to asthma severity for many years and more evidence has been accumulating ever since. Preliminary evidence shows the beneficial effects of high-altitude treatment in patients with severe refractory asthma on symptoms, lung function and oral corticosteroid requirement, irrespective of atopic status. In this narrative review, we will discuss why high-altitude treatment might be a promising therapeutic option for patients who suffer from this disabling disease.