Risks for infection in patients with asthma (or other atopic conditions): is asthma more than a chronic airway disease?

Most of the research effort regarding asthma has been devoted to its causes, therapy, and prognosis. There is also evidence that the presence of asthma can influence patients' susceptibility to infections, yet research in this aspect of asthma has been limited. There is additional debate in this field, with current literature tending to view the increased risk of infection among atopic patients as caused by opportunistic infections secondary to airway inflammation, especially in patients with severe atopic diseases. However, other evidence suggests that such risk and its underlying immune dysfunction might be a phenotypic or clinical feature of atopic conditions. This review argues (1) that improved understanding of the effects of asthma or other atopic conditions on the risk of microbial infections will bring important and new perspectives to clinical practice, research, and public health concerning atopic conditions and (2) that research efforts into the causes and effects of asthma must be juxtaposed because they are likely to guide each other.