A Rare Complication of Herpes Zoster: Segmental Zoster Paresis

Segmental zoster paresis (SZP) is a rare complication of herpes zoster (HZ) that results in focal weakness of the extremity in the myotome that corresponds to dermatomal involvement.We present a case of an 80-year-old female with a resolving HZ rash on her left leg and buttocks that presented with left leg weakness for two weeks. The patient's rash preceded the left leg weakness by two weeks. The exam revealed erythematous macular and crusting lesions in the left L3/L4 distribution. The left thigh was flaccid with 1/5 knee extension strength with an absent patellar reflex. Lumbar spine magnetic resonance imaging (MRI) revealed enhancement of the left L4 roots, suggestive of inflammation or neuropathy. The patient was discharged on gabapentin, amitriptyline, and a two-week prednisone taper. In this case study, we present SZP, a rare complication that occurs in approximately 3% of HZ patients. The majority of SZP cases occur on the face or upper extremity, whereas our patient had SZP of the lower extremity. This case emphasizes the importance of maintaining a comprehensive differential diagnosis and highlights that SZP should be considered in patients who present with acute weakness in an extremity.