Rhinosinusitis (RS) refers to the presence of inflammation in the paranasal sinuses mucosa (i.e., the lining of the sinuses) and the contiguous mucosa of the nasal passages. When it is present for less than one month, the condition is termed acute rhinosinusitis. If the inflammation is present for more than 12 weeks, then chronic rhinosinusitis is present. If the duration is between four and 12 weeks, the rhinosinusitis should be considered subacute. Recently, chronic rhinosinusitis (CRS) has been further classified as CRS with nasal polyps and CRS without nasal polyps.
The causes of RS are diverse, and often it is not possible to precisely identify a specific cause.
Furthermore, RS may mimic other conditions, including isolated inflammation of the nasal lining (rhinitis). Precise diagnosis includes a detailed history, examination, specific testing and imaging studies, and serves as the foundation for appropriate treatment.