Background <p>Reactivation of the varicella zoster virus can result in a neurological complication, including segmental zoster paresis. Outpatient management of upper limb paresis due to herpes zoster is rarely reported, making this case clinically relevant.</p> Case presentation <p>We describe a 70-year-old Japanese woman initially diagnosed with cervical spondylosis who later developed a vesicular rash and progressive left arm weakness. Neurological examination and nerve conduction studies revealed motor involvement consistent with segmental zoster paresis. She was treated with antiviral therapy, physical rehabilitation, analgesics, and adjunctive vitamin supplementation, leading to full recovery.</p> Conclusion <p>This case shows the feasibility of outpatient management in select cases of segmental zoster paresis and the importance of timely intervention. Herpes zoster should be considered in the differential diagnosis of acute unilateral arm paresis, especially in cases involving radicular pain.</p>