Pterygoid sinusitis is mostly caused by the blockage of the pterygoid sinus orifice which causes secretions in the pterygoid sinus not to be easily discharged, bacterial invasion and infection, and decreased immunity. 1. If the patient has inflammation of the nasal cavity, sinus, obstructive diseases or incomplete development of the pterygoid sinus, it will cause the blockage of the pterygoid sinus opening, so that the secretions in the pterygoid sinus can not be discharged, which can easily lead to mucous pus accumulation in the pterygoid sinus cavity to form pterygoid sinusitis. 2. Patients suffering from upper respiratory tract infections, viruses and bacteria from the upper respiratory tract invade the mucous membrane of the pterygoid sinus, which can also cause pterygoid sinusitis. 3. Trauma to the pterygoid sinus can induce a large number of blood clots in the pterygoid sinus, and the blood clots can cause inflammation in the pterygoid sinus. 4. If the patient’s physical condition is relatively weak, the body resistance and immunity is relatively poor, it may induce the patient to appear pterygosinusitis. If you are not feeling well, it is recommended that you go to the hospital for treatment in time to avoid delaying your condition.