Contributor: Gordon K. Klintworth
Sinusitis may be acute [sinusitis - acute] or chronic [sinusitis - chronic] and it is frequently preceded by a rhinitis. The causes of sinusitis include infections and allergies [sinusitis - allergic]. The allergic reaction may be caused by a fungus [sinusitis - allergic fungal] of which Aspergillus is an important allergen. Rarely sinisitis is a manifestation of Kartagener syndrome. Sinusitis may spread into the orbit and cause an orbital cellulitis [cellulitis - orbit]. Other complications of sinusitis include empyema or a mucocele of the affected paranasal sinus. Surgical procedures on the paranasal sinuses may injury the extraocular muscles, such as the rectus muscle injury may follow sinus surgery.