Objective: The primary reason for this review is to discuss the relationshi
p between upper and lower airways at various levels with the emphasis on co
mmon pathophysiologic mechanisms, and how treatment of the upper airways wi
ll benefit the lower airways.
Data Sources: The main source of information is derived from original artic
les and books, with an extensive bibliography included.
Study Selection: Studies were derived almost exclusively from articles and
reviews in peer-reviewed journals.
Results: The prevalence of rhinitis and asthma are both increasing. Common
to both the upper and lower airways are the triggers, many of the inflammat
ory cells and mediators, and the treatment modalities. By contrast, there a
re organ-specific differences in the reaction to various stimuli in the nos
e or lung, with each organ manifesting its own vocabulary of response.
Conclusions: There are meaningful relationships between upper and lower air
ways at various levels of our understanding. Differential responses to medi
cations help us better understand pathogenic mechanisms in rhinitis and ast
hma. Further, treatment of the upper airways provides additional benefit to
the lower airways.