Paroxysmal Neuropathic Pruritus in Patients With Chiari Malformation Type I: A Rare Phenotype.

Chiari malformation type I (CM-I) is a group of deformities in the posterior fossa and hindbrain, including the pons, cerebellum, and medulla oblongata. Paroxysmal pruritus in CM-I has been reported only once before in the literature. This study was a cross-sectional study over 12 months at a tertiary care pediatric hospital involving children aged one to 18 years with CM-I presenting with paroxysmal itching. Three patients with CM-I presented with severe episodes of paroxysmal itching. Patient 3 was started on carbamazepine therapy for seizures, and incidentally, his itching subsided. The pruritus of neuropathic etiology has been reported to be associated with syringomyelia, spongiform encephalopathies, autoimmune disorders like multiple sclerosis, patients with end-stage renal failure on dialysis, and neoplasms. Antihistamines and antiallergics are ineffective in treating these patients, reiterating a central mechanism for pruritus. At present, no drugs have been approved for the treatment of neuropathic pruritus specifically. The commonly used treatments for neuropathic itch are antiseizure medications, tricyclic antidepressants, gabapentinoids, ketamine, and oral kappa opioids, including butorphanol and difelikefalin. Better structured prospective studies are needed to analyze the prevalence and scales to assess disability caused due to neuropathic itch in CM and may enhance understanding in this area.