Is herpes simplex virus (HSV) an etiological factor in Bell palsy (idiopathic facial paralysis) (IFP)?

Updated: Jun 14, 2019
  • Author: Danette C Taylor, DO, MS, FACN; Chief Editor: Selim R Benbadis, MD  more...
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In the past, situations that produced cold exposure (eg, chilly wind, cold air conditioning, or driving with the car window down) were considered to be the only triggers for Bell palsy. Several authors now believe, however, that the herpes simplex virus (HSV) is a common cause of Bell palsy, though a definitive causal relationship of HSV to Bell palsy may be difficult to prove because of the ubiquitous nature of HSV.

The hypothesis that HSV is the etiologic agent in Bell palsy holds that after causing primary infection on the lips (ie, cold sores), the virus travels up the axons of the sensory nerves and resides in the geniculate ganglion. At times of stress, the virus reactivates and causes local damage to the myelin.

This hypothesis was first suggested in 1972 by McCormick. [15] Autopsy studies have since shown HSV in the geniculate ganglion of patients with Bell palsy. Murakami et al performed polymerase chain reaction (PCR) assay testing on the endoneural fluid of the facial nerve in patients who underwent surgery for Bell palsy and found HSV in 11 of 14 cases. [16]

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