Chronic sinusitis can be divided into infectious and noninfectious forms. Unlike acute sinusitis, viral infections play practically no role in infectious chronic sinusitis.
In chronic infectious sinusitis, the common organisms causing persistent sinus disease are well known.
Bacterial causes of chronic sinusitis
More than one bacterial strains are typically present at the same time in chronic sinusitis. This is quite different from acute sinusitis where only one kind of bacteria usually predominates. Anaerobic organisms are frequently present in chronic sinusitis. Sinus cultures are typically not required. If a culture is needed, it can be taken through a nasopharyngolaryngoscope although contamination from nasal bacteria may occur. Aspiration of the sinus cavities offers the most accurate results but is rarely used because of the discomfort and potential for complications.