Erenumab for Idiosyncratic Facial Pain

Inclusion Criteria: 1. Adults 18 years of age and older presenting to Duke Head \& Neck Surgery and Communications Sciences clinic for evaluation of rhinosinusitis and/or facial pain or pressure. 2. Symptoms are present at least 10 days a month for the last 3 months as reported by subject. 3. Symptoms must include midfacial pain or uncomfortable pressure (may be unilateral or bilateral), which is defined as pain in the regions overlying the maxillary, ethmoid, frontal sinuses either together or individually. 4. Nasal endoscopy in the last three months shows no signs of inflammation (i.e. thick drainage, polyps, watery edema in the middle meatus or spheno-ethmoid recess (mild edema permitted). 5. Sinus CT scan or MRI within 12 months of enrollment during a symptomatic period shows no more than scattered minimal mucosal edema or mucous retention cyst with patent infundibula bilaterally. For subjects with a CT scan more than 12 months old or just an MRI, a CT will be repeated for study purposes. For patients with CT scans less than 12 months old, a CT will be repeated for study purposes if the subject has changes in symptoms suggestive of sinusitis. 6. Ability to read/write English. 7. Has a smart phone, ipod or iPad touch for completion of the EMA on a daily basis. Exclusion Criteria: 1. Hypersensitivity to erenumab or to any of the drug components (acetate, polysorbate, and sucrose). 2. Previous exposure to erenumab or any other CGRP inhibitor in the six months prior to treatment. 3. Allergy to latex. 4. Inability to differentiate facial pain from other headaches. 5. Non-English speaking or unable to provide written informed consent. 6. On a preventative migraine medication (see below) during the 30 day lead-in period: * Category 1: Divalproex sodium, sodium valproate * Category 2: Topiramate * Category 3: Beta blockers (for example: atenolol, bisoprolol, metoprolol, nadolol, ebivolol, pindolol, propranolol, timolol) * Category 4: Tricyclic antidepressants (for example: amitriptyline, nortriptyline, protriptyline) * Category 5: Serotonin-norepinephrine reuptake inhibitors (for example: venlafaxine, desvenlafaxine, duloxetine, milnacipran) * Category 6: Flunarizine, verapamil * Category 7: Lisinopril, candesartan 7. Received botulinum toxin (Botox) to the head and neck for migraines in the last four months. 8. More than one major open surgery of the nose or sinuses for sinonasal cancer. 9. History of uncontrolled or unstable blood pressure. 10. History of liver failure. 11. History of metastatic malignancy in the last five years or actively undergoing treatment for cancer. 12. Active seizure disorder or other significant neurological conditions other than migraine. 13. Myocardial infarction (MI), stroke, transient ischemic attack (TIA), unstable angina, or coronary artery bypass surgery or other revascularization procedure within 12 months prior to screening. 14. History or evidence of any other unstable or clinically significant medical condition that in the opinion of the sponsor-investigator/ Principal Investigator, would pose a risk to subject safety or interfere with the study evaluation, procedures or completion. 15. Evidence of drug or alcohol abuse or dependence within 12 months prior to screening, based on medical records or patient self-report. 16. Pregnant or breastfeeding, or expecting to conceive during the study, including through 16 weeks after the last dose of investigational product or placebo 17. Female subject of childbearing potential who is unwilling to use an acceptable method of effective contraception during treatment with investigational product or placebo through 16 weeks after the last dose of investigational product. Female subjects not of childbearing potential are defined as any female who is post-menopausal by history, defined as: * Age ≥ 55 years with cessation of menses for 12 or more months, OR * Age \< 55 years but no spontaneous menses for at least 2 years, OR * Underwent bilateral oophorectomy, bilateral salpingectomy, or hysterectomy 18. Unlikely to be able to complete all protocol required study visits or procedures. 19. Currently receiving treatment in another investigational device or drug study.