Anaerobes are also important in chronic sinusitis because they predominate in brain abscesses associated with sinus infections. Viruses seldom cause clinical sinusitis. In immunocompromised patients, sinusitis may also be caused by Candida, Alternaria, Pseudomonas, Nocardia, Le gionella, atypical mycobacteria, and certain parasites. Finally, noninfectious processes must be considered in the differential diagnosis of sinusitis. Allergic or vasomotor rhinitis is by far the most common noninfectious cause of sinus symptoms.
Acute sinusitis is treated with analgesics and topical heat for patient comfort.
Decongestants are of paramount importance. Pseudoephedrine can be administered orally or by nasal spray. The danger of rebound after short-term use of nasal spray has probably been exaggerated. This procedure can be repeated every 4 hours for several days when needed. Antihistamines may thicken secretions and are therefore less likely to promote drainage.