ABSTRACT
A complete understanding of the pathophysiology of rhinosinusitis remains elusive, but several infectious and inflammatory pathways have been identified. Microbial agents, such as viruses, bacteria, and fungus, are wellestablished etiologies of rhinosinusitis, especially in the acute situation, but numerous host and environmental factors have also been implicated, either individually or in combination in the chronic disease state. This chapter will discuss these various factors as well as the individual and symbiotic roles they play in the development of rhinosinusitis. Particular emphasis will be placed on current hypotheses regarding the etiology of chronic rhinosinusitis (CRS) and important new areas of research such as biofilms, superantigens (sags), and osteitis.
