A case of relapsing-remitting facial palsy and ipsilateral brachial plexopathy caused by HSV-1.

The etiologies of Bell's palsy and brachial neuritis remain uncertain, and the conditions rarely co-occur or reoccur. Here we present a woman in her twenties who had several relapsing-remitting episodes with left-sided facial palsy and brachial neuropathy. The episodes always started with painful left-sided oral blisters. Repeat PCRs HSV-1 DNA from oral vesicular lesions were positive. Extensive screening did not reveal any other underlying cause. Findings on MRI T2-weighted brachial plexus STIR images, using a 3.0-Tesla scanner during an episode, were compatible with brachial plexus neuritis. Except a mannose-binding lectin deficiency, a congenital complement deficiency that is frequently found in the general Caucasian population, no other immunodeficiency was demonstrated in our patient. In vitro resistance to acyclovir was tested negative, but despite prophylactic treatment with the drug in high doses, relapses recurred. To our knowledge, this is the first ever reported documentation of relapsing-remitting facial and brachial plexus neuritis caused by HSV-1.