To propose long term prospective studies on the effectiveness of calcitonin gene-related peptide [CGRP]monoclonal antibodies in SUNA.

SUNA is a rare disabling Trigeminal autonomic cephalalgia [TAC] without optimal response to guideline based therapeutic options. We report a case of chronic refractory SUNA with excellent response to Erenumab, a CGRP antagonist.

A 51-year-old female presented to our University Headache Clinic with nine-month history of strictly right sided periorbital /temporal daily attacks of severe, sharp stabs of pain lasting two to ten seconds, recurring up to hundred/day. Associated symptoms were ipsilateral rhinorrhea, tearing and fullness in the ear. Repeated neurological evaluations and comprehensive diagnostic studies were normal. There was no response to extensive trials of acute and preventive medications including indomethacin, lamotrigine, and gabapentin or to scalp nerve/SPG blocks and Botox. Erenumab 70 mg q 30 days was started with dose increase to 140 mg after 3 months.

There was no response for the first 3 months, but notable improvement was reported with the higher dose after the third month. By the seventh month, the patient achieved total relief of head pains until 25 days after the injection with recurrence of milder attacks closer to the next dose suggesting wearing off effect. This response has been maintained without any adverse effects up to 31 months to the date of this report. 

This patient met the ICHD-3 diagnostic criteria for chronic SUNA, refractory to standard treatment. Excellent response to Erenumab was gained only by the 7^th month of therapy. Evidently, CGRP plays a significant role in the pathogenesis of TAC.We propose that CGRP antagonists could be used as an effective and safe treatment option for SUNA. To our knowledge, this is the first case report of the efficacy of Erenumab in the treatment of SUNA.