Extent of Pain Distribution in Entrapment of the Greater Occipital Nerve Identified Through Skin Lesions of Herpes Zoster Involving the Greater Occipital Nerve

Herpes zoster (HZ) involving the upper cervical nerves (C2-C4), which innervate the posterior head, is rare. There have also been few reports of HZ lesions involving the greater occipital nerve (GON), which refers to the medial branch of the dorsal ramus of the second cervical nerve. Pain due to GON entrapment radiates not only to the temporo-occipital region, but also to the ear, retro-auricular and sub-auricular areas of the neck, the angle of the jaw, and the posterolateral neck. Herein, we present the case of a patient who underwent decompression surgery for referred trigeminal pain due to GON entrapment and who developed HZ one week later. Skin lesions of HZ involving the GON occurred not only in the occipital area but also in the ipsilateral ear, auricle, posterior and anterolateral neck. This case of HZ involved all cutaneous areas innervated by the C2, C3, and C4 spinal nerves. The extent of the skin lesions indicated where the pain from the GON radiated.