<s>[INST] Hello doctor, I require some information about sinus infection. 1. What are sinus infections, and what causes it? 2. Suggest some reasons why we are getting frequent sinus infections, and what should done? [/INST] Hello. 1. Sinus infections (sinusitis) are swelling or inflammation of the tissue lining the sinuses. 2. Causes include a virus, bacteria, fungus, allergies, polyps, tooth infections. 3. Blockage of the nose, especially if you are allergic or having nasal polyps makes you prone to have frequent sinusitis. Plus, congenital illness or weak immunity also puts at risk for sinus infections more often than healthy patients. Prevention consists of keeping nasal pathways clean, stay well hydrated, avoid dry air places. You can use air humidifiers to moisten the air. Eat healthily, get enough sleep, and exercise more. </s>