Facial paralysis may be congenital in nature, related to trauma or tumors in the salivary glands or skull base. It can also be caused by conditions such as bell’s palsy or a stroke.
Bell’s Palsy
Bell’s palsy is the most common cause of paralysis in the face. It begins suddenly and can worsen over 48 hours. This condition results from damage or inflammation to the facial nerve which can cause one side of the face to droop.
Bell’s palsy can strike anyone at any age. It occurs most often in pregnant women, and people who have diabetes, influenza, a cold, or another upper respiratory ailments.
Bell's palsy is not considered permanent. But in rare cases, it does not disappear. Currently, there is no known cure for Bell's palsy. Recovery, though, usually begins 2 weeks to 6 months from the onset of the symptoms. Most people with Bell's palsy recover full facial strength and expression.
Stroke
A stroke is a sudden loss of brain function caused by a lack of blood flow and oxygen. A stroke can cause facial drooping when nerves that control the muscles in the face become damaged. Most commonly, the lower part of one side of the face is affected. The corner of the mouth can become weak, resulting in drooling. Difficulty speaking may also occur.