Sinusitis, also known as sinus infection, is a symptom caused by inflammation of the sinus mucosa. Common symptoms include snot, stuffy nose, and facial pain. Other signs and symptoms may include fever, headache, poor sense of smell, sore throat and cough. Sinusitis can be caused by infections, allergies, air pollution or structural problems in the nose. Most cases are caused by viral infections. However, its specific molecular mechanism is not known to us.