The most common form of cranial mononeuropathy VII, Bell's palsy causes patients to have temporary facial paralysis. Patients with Bell's palsy have damage to the seventh cranial nerve, called the facial nerve. Symptoms of Bell's palsy include weakness and tingling in the face, difficulty eating and drinking, headache, and dry mouth. MedlinePlus points out that while the cause of Bell's palsy is not always clear, certain infections may cause the nerve damage.
Herpes Simplex
MayoClinic.com notes that the herpes simplex virus may be the most common cause of Bell's palsy. Two types of herpes simplex viruses exist that can cause Bell's palsy: herpes simplex virus type 1 and herpes simplex virus type 2. Herpes simplex virus type 1 causes oral herpes, or cold sores, and spreads through contaminated saliva. Herpes simplex virus type 2 causes genital herpes and spreads through sexual contact. Both herpes simplex viruses cause Bell's palsy when the facial nerve swells in response to the infection.
Diabetes
MedlinePlus points out that diabetes may contribute to the onset of Bell's palsy. With diabetes, patients can have a resistance to insulin, too little insulin or both problems. These insulin problems cause blood sugar regulation issues for diabetes patients. As a result, patients can have high blood sugar. A complication of diabetes is diabetic neuropathy, in which nerve injuries result from a decreased blood flow and high blood sugar.
Herpes Zoster
Herpes zoster, which causes shingles and chickenpox, may cause Bell's palsy, according to MayoClinic.com. After chickenpox, the herpes zoster virus stays inactive in patients' nerve cells. The American Academy of Dermatology explains that a weakened immune system may trigger the reactivation of the herpes zoster virus.
Sarcoidosis
MedlinePlus notes that sarcoidosis, which causes inflammation of certain body parts, may cause Bell's palsy. The areas of inflammation include the lymph nodes, skin, lungs, eyes and liver. Sarcoidosis may cause inflammation of the seventh cranial nerve while it travels through the skull, resulting in Bell's palsy.
Epstein-Barr
MayoClinic.com explains that the virus that causes mononucleosis, Epstein-Barr, is linked to Bell's palsy. The Epstein-Barr virus is part of the herpesvirus family, which also contains the herpes simplex viruses and herpes zoster virus. The Centers for Disease Control and Prevention notes that up to 95 percent of American adults between ages 35 and 40 have been infected with the Epstein-Barr virus. When the infection occurs during adolescence to young adulthood, the CDC adds that 35 to 50 percent of infections result in mononucleosis.
Lyme Disease
Another inflammatory condition, Lyme disease, may cause Bell's palsy in some patients. Caused by the bacterium Borrelia burgdorferi, Lyme disease spreads through tic bites. MedlinePlus points out that in the advanced stages of Lyme disease, patients can have facial paralysis, or Bell's palsy, as well as nerve damage.
Cytomegalovirus
Also a member of the herpesvirus family, cytomegalovirus may cause Bell's palsy. MedlinePlus notes that 50 to 80 percent of American adults have become infected with the cytomegalovirus by age 40. Cytomegalovirus remains in the patient's body but is only a problem among people with weakened immune systems.
