A condition caused by the inflammation and swelling of the facial nerve that paralyses the facial muscles. It usually only affects one side of the face and it is very noticeable if the patient tries to smile or blink their eyelids. The onset of the paralysis is frequently associated with the patient having been exposed to a cold draught on the side of the face (for example driving with the car window open). Treatment is sometimes assisted with the use of anti-inflammatory agents such as cortisones. Many cases will return to normal after 4 to 6 weeks but it is important to seek medical advice in the beginning.