Migraine recurrence is common amongst pediatric patients being discharged from the emergency department after treatment for migraine. Despite the commonality of migraine recurrence within the week following discharge, no known effective therapies are available in the pediatric population, though dexamethasone has been established as efficacious in the adult migraine population. The proposed study will randomly assign children and adolescents visiting the emergency department (ED) for migraine to receive either one dose of oral dexamethasone or oral placebo. Twenty patients will be recruited to this randomized, double-blind, pilot trial over a 6 month period, and the aim of the study will be to determine the feasibility and acceptability of the protocol.

Migraine is common in the pediatric emergency department. Unfortunately, somewhere between one third and two thirds of children and adolescents will have recurrence of their migraine within a week of discharge from the emergency department. Although there is strong evidence from adult studies that dexamethasone can prevent migraine recurrence, there is no evidence on how to prevent recurrence in children and adolescents. The proposed study will randomly assign children and adolescents visiting the Children's Hospital of Eastern Ontario (CHEO) emergency department (ED) for migraine to receive either one dose of oral dexamethasone or oral placebo. Twenty patients will be recruited to this randomized, double-blind, pilot trial over a 6 month period, and the aim of the study will be to determine the feasibility and acceptability of the protocol.

Patients will be recruited from the CHEO ED. Research volunteers will screen patients with a triage diagnosis of 'headache', 'migraine' or a related triage diagnosis for eligibility. Patients who meet eligibility criteria will be approached by a research assistant who will initiate the consent process. Informed consent will be sought through both verbal explanation and in written form, from participants 14 years and over and from the parent(s) or guardian(s). For participants under the age of 14 years, verbal and written assent will be sought.

Consenting participants will be randomized to receive one dose of oral dexamethasone 0.6mg/kg to a maximum of 15mg or one dose of oral matched placebo. Randomization will be stratified by baseline migraine duration: 1) less than 2 hours, 2) 2 hours to less than 24 hours and 3) 24 hours and greater. A list of randomization codes will be generated over the computer by a biostatistician and randomization will occur in blocks of four. Research personnel will not have access to the randomization code list with group assignments. Only the research pharmacists will have access to the list.

The research assistants will collect outcome data from the participants and store it into Research Electronic Data Capture (REDCaP), a secure, encrypted web-based platform. Participants will have the option of completing follow-up via email questionnaires or over the telephone. Follow-up will take place 48 hours and 7 days after discharge. The purpose of follow-up will be to assess whether or not participants had recurrence of their migraine, and to collect other follow-up outcome data and safety data. The research assistants, participants, research personnel and clinical personnel will all be blinded to group assignment. Only the research pharmacists, who will not interact with anyone in the study directly, will have access to group assignment information.

Data analyses will be carried out for exploratory purposes, and the groups (dexamethasone vs. placebo) will be compared with regards to: baseline data, 48 hour migraine recurrence rates, 7 day migraine recurrence rates, the proportion of participants achieving pain freedom at 2 hours and maintaining it at 48 hours, patient satisfaction data and adverse events.

Inclusion Criteria:

1. Between the ages of 8 and 18 years (ie. > 8.0 years and < 18.0 years)
2. Diagnosed with migraine according to a modified version of International Classification of Headache Disorders 3rd edition (ICHD-3, beta version) where criterion A (ie. minimum of 5 prior episodes meeting criteria B-D) has been removed to increase sensitivity of diagnosis in the emergency department setting

Exclusion Criteria:

1. Received a dose of a steroid medication in the past 7 days
2. Known allergy to dexamethasone
3. Immunosuppressed
4. Cushing's syndrome
5. Known diabetes mellitus
6. Known peptic or duodenal ulcer or other major gastrointestinal illness (ex. ulcerative colitis)
7. Known myasthenia gravis
8. Glaucoma
9. Febrile at triage
10. History of head trauma in the past 7 days
11. Presence of any known active infection (eg. on antibiotics or antivirals, diagnosed with active infection in the ED, etc)
12. Current secondary headache (as per the treating physician's clinical impression)

One participant in the dexamethasone group withdrew from the study prior to receiving the study intervention and is not included in the analyses.

Adverse event data were collected at discharge and for the first 7 days after discharge

The medication (dexamethasone) has potential to cause immunosuppression.

This study was designed as a pilot trial to assess trial protocol feasibility. Statistical hypothesis testing was not conducted on any of the outcome variables because of the small sample size and the inability to draw inferences from this data.