Chronic sinusitis is defined as sinus inflammation of at least 3 months. It is often a sequel to an acute sinus infection with an end result of chronic impairment of sinus drainage function. Persistent inflammation prevents proper mucociliary clearance leading to chronic mucous retention. Patients may have sinonasal polyps. The prolonged pressure from inspissated mucous secretions and polyps can result in complications with erosion of the common walls between the sinuses and the orbit or skull base. Risk factors include environmental allergies, cystic fibrosis, and other mucociliary clearance disorders, congenital or acquired immunodeficiency, anatomic variation of the sinonasal airway, and exposure to secondhand smoke. Children's paranasal sinuses are not fully formed at birth, reaching adult configuration by adolescence. Patients often have longstanding symptoms that include nasal congestion, hyposmia, postnasal drip, facial pressure and headache, and presentations to the ED often reflect a complication, including mucocele, orbital infection, meningitis, extradural abscess, and intracranial abscess. Signs and symptoms may include fever, proptosis, periorbital swelling, vision loss, severe headache, mental status changes, and meningeal signs.