Nasobronchial interaction mechanisms in allergic airways disease

During the past few decades, the incidence of sensitization to inhaled allergens as well as allergic airways disease has grown steadily. Genetic and environmental factors are recognized as etiologic factors in the development of allergic airway disease, with allergic rhinitis often preceding the development of asthma. Allergic rhinitis is considered a risk factor for the development of asthma, and almost all allergic asthmatic patients have rhinitis. Insight into the risk factors responsible for allergic airways disease and the interaction between the involved organs results in a better diagnostic and therapeutic approach in global airway allergy syndrome.

Recent studies have shown that local tissue factors, such as microbial stimuli and systemic inflammatory mechanisms, play a role in the clinical expression of the allergic airway syndrome. In addition, impaired nasal function affects the lower airways of asthmatic patients via different pathways. To date, most human and animal data point towards a systemic pathway linking the upper and lower airways, involving both bloodstream and bone marrow. Recent clinical trials and current guidelines underline the importance of an integrated treatment strategy involving both ends of the respiratory tract.

This review provides an overview of recent epidemiological and immunopathologic evidence concerning the link between upper and lower airways in allergic disease and its therapeutic implications.