Your risk of sinusitis increases if you have recently had a cold, another viral or bacterial infection, or an upper respiratory tract infection. Also, chronic nasal allergies (allergic rhinitis) can lead to sinusitis.
Sometimes a deviated septum, broken nose, or growths such as nasal polypscan make you more susceptible to sinus infections. Problems with nasal structure can prevent the proper flow of mucus from the sinuses into the nose.
Other factors that increase your risk for getting sinus infections include having asthma, smoking, air pollution, overuse of decongestant sprays, cold weather, rapid air pressure changes (such as from flying or scuba diving), and swimming in contaminated water. Also, using continuous positive airway pressure (CPAP) to treat sleep apnea may increase the risk of sinusitis.