What Causes a Sinus Infection?
Rhinitis, a medical term used to describe symptoms of nasal irritation and inflammation, can cause a sinus infection. Typically caused by allergies or a cold, the infection only affects your nasal passages. Sinus and nasal passages become inflamed, congested, and swollen as they attempt to purge the nasal passage of inhaled irritants.
Some people can have chronic sinusitis that is not caused by an infection and can develop chronic nasal irritation and inflammation.