Herpes zoster is a common nervous disease known since ancient times. Denny-Brown, Adams, and Fitzgerald, in an article based upon contributions of von Bärensprung, Head and Campbell, Lhermitte and Nicolas, and three cases of their own, sketched the broad outlines of this condition as follows:
"The disease is probably due to a filtrable virus, similar to, if not identical with, that of varicella, which provokes an acute inflammatory reaction in isolated spinal or cranial sensory ganglia, the posterior gray matter of the spinal cord and the adjacent leptomeninges. The clinical manifestations are a vesicular cutaneous eruption, radicular neuralgia and, less often segmental palsies and sensory loss....
"In view of the large number of sensory ganglia which may be involved, the clinical possibilities are manifold. In the region of the cranial nerves two special syndromes are frequent, namely, "opthalmic herpes" and "geniculate herpes." The pathologic changes in the Gasserian ganglion in
GULDBERG-MÖLLER J, OLSEN S, KETTEL K. Histopathology of the Facial Nerve in Herpes Zoster Oticus. AMA Arch Otolaryngol. 1959;69(3):266–275. doi:10.1001/archotol.1959.00730030274003