Does rhinitis lead to asthma?

Rhinitis and asthma are commonly linked even if the precise pathological mechanisms explaining the relationship are not fully understood. Although there is increasing evidence that rhinitis may influence the development of asthma, there remain many gaps in our understanding of the processes involved. The complexity of this relationship is mainly due to the multiple interactions between genetic background, environmental factors and the specific host reaction. Epidemiological surveys have highlighted significant clinical associations and identified some factors that favour the progression from rhinitis to asthma. Basic research has demonstrated numerous similarities in inflammatory and immunological mechanisms.