Segmental Zoster Paresis Accompanied by Horner's Syndrome.

We herein report a 90-year-old immunocompromised woman who developed right upper limb weakness and right ptosis with a miotic pupil 1 week after oral therapy for zoster on the right T2 dermatome. The right pupil was dilated with instillation of 1% apraclonidine, indicating Horner's syndrome. The patient was treated with intravenous acyclovir and methylprednisolone. Focal weakness related to zoster, generally known as segmental zoster paresis, improved over five months, but Horner's syndrome remained. We suggest that aggressive intravenous treatment should be considered for rare cases of zoster that occur with a combination of these two neurological conditions.