背景：ChiariI畸形（ChiariI）定义为一个或两个小脑扁桃体在颅骨大孔下方向下移位，并拥挤改变脑脊液流量。它可能与脊髓内充满液体的空腔的发展有关，脊髓空洞症.神经系统缺陷或症状可发生在脊髓空洞症的解剖学受累水平。
方法：一个年轻人到皮肤科诊所评估瘙痒性皮疹。认识到神经性瘙痒的独特左“斗状”分布导致结节性痒疹，他被当地急诊科的神经科转介接受进一步评估。经过额外的病史和神经系统检查，磁共振成像证实ChiariI伴有相关的syrogbulbia和延伸至脊髓T10/11的syrinx。syrinx向前延伸到脊髓的左实质，涉及背角，解释他神经性瘙痒的病变。后颅窝开颅术和C1椎板切除术后，瘙痒和皮疹的感觉得以缓解。
结论：神经性瘙痒，除了疼痛,可能是ChiariI伴有脊髓空洞症的症状.没有明显皮肤触发的局灶性瘙痒应提示提供者考虑中枢神经病理学。虽然许多ChiariI患者无症状，神经功能缺损和脊髓空洞症的存在，是神经外科评估的适应症。
BACKGROUND: Chiari I malformation (Chiari I) is defined by the downward displacement of one or both cerebellar tonsils below the foramen magnum of the skull with crowding altering cerebrospinal fluid flow. It can be associated with the development of a fluid-filled cavity within the spinal cord, syringomyelia. Neurological deficits or symptoms can occur at the level of anatomic involvement of syringomyelia.
METHODS: A young man presented to dermatology clinic for evaluation of a pruritic rash. Recognizing a unique left \"cape-like\" distribution of neuropathic itch leading to prurigo nodularis, he was referred for further evaluation by neurology in the local emergency department. After additional history and neurological exam, a magnetic resonance imaging confirmed Chiari I with an associated syringobulbia and a syrinx extending to T10/11 of the spinal cord. Anteriorly the syrinx extended into the left parenchyma of his spinal cord involving the dorsal horn, a lesion explaining his neuropathic itch. The sensation of itch and rash resolved after posterior fossa craniectomy and C1 laminectomy with duraplasty.
CONCLUSIONS: Neuropathic itch, in addition to pain, can be a symptom of Chiari I with syringomyelia. Focal pruritus without an obvious cutaneous trigger should prompt providers to consider a central neurological pathology. While many patients with Chiari I are asymptomatic, the presence of neurological deficits and syringomyelia, are indications for neurosurgical evaluation.
