Zoster paresis of the shoulder. Case report and review of the literature.

More than 95% of people in the United States are infected with the varicella zoster virus at some time in life, and this infection usually is manifested as chicken pox during childhood. The virus then establishes a latent infection of sensory ganglia, from which it may reactivate many years later to cause herpes zoster (shingles), a cutaneous painful rash along a dermatomal distribution. Less commonly, the varicella zoster virus may result in myotomal motor weakness or paralysis in addition to a painful dermatomal rash. A case of unilateral left C5-C6 segmental paresis attributable to herpes zoster in an otherwise healthy individual and a current review of the literature are presented. A case of zoster paresis of the shoulder muscles is presented to remind the orthopaedic community that this diagnosis may be confused with other diagnoses, including rotator cuff tear, and should be considered in the differential diagnosis of shoulder pain and shoulder girdle muscle weakness.