What causes chronic sinusitis?

The sinuses are air-filled spaces around the nose. Their lining makes mucus, which normally drains through small openings into the nose. Swelling can narrow those openings, leaving mucus trapped and making the nose feel blocked. Poor drainage can maintain inflammation and create pressure, facial discomfort, reduced smell or thick nasal discharge.

Allergic rhinitis can repeatedly inflame the nasal lining and make sinus drainage more difficult. Other contributors include nasal polyps or other tissue growths, a narrow or altered nasal passage, exposure to smoke and strong airborne irritants, and infections that do not fully settle. Several factors may act together, so finding one cause does not exclude another.

Arrange a medical assessment if symptoms continue or keep returning. A clinician may ask about allergy symptoms, previous infections, smell changes, medicines and irritant exposure, then examine the nose. Treatment is guided by the cause and may focus on reducing inflammation, improving drainage or treating an underlying allergy or infection.

Avoid cigarette smoke and other known nasal irritants where possible. Do not start antibiotics or use decongestant sprays for longer than advised; these do not address every cause and prolonged spray use can worsen congestion.

Seek prompt medical care for swelling or redness around an eye, changes in vision, severe headache, confusion, a stiff neck, or rapidly worsening facial swelling. These symptoms can signal a complication that needs urgent assessment.

For less urgent symptoms, book an appointment when blocked breathing, facial pressure, discharge or reduced smell persists, interferes with sleep, or returns frequently. A clinician can check whether allergies, polyps or another nasal problem is sustaining the inflammation.

Ask: Could allergies be contributing to my sinus symptoms? Is there a polyp or drainage problem? Which symptoms would suggest an infection? What treatment should I use, and how long should I try it before follow-up?