What are the possible causes of bells palsy?

Viral infection: Bell's palsy is one reason people develop facial paralysis. True bell's palsy is felt to be caused by a viral infection of the facial nerve leading to swelling of the nerve and damage to it caused by decreased blood flow. Steroids are very helpful in treating this. Some people incorrectly term facial paralysis "bell's palsy." this is not correct, you must exclude other causes of facial paralysis.

Multiple: Facial nerve pressure, viruses such as herpes simplex, cold sores, herpes zoster, epstein-barr, rubella, (german measles), mumps virus, tumors and strokes, are all thought to be possible causes.