Headaches in children are very common and are a source of significant distress for the patient and their family. Migraines are the most common headache disorder in children and are associated with episodic pain and other symptoms such as nausea and sensitivity to light and sound that can impair a child's ability to participate in daily activities and lead to missed school or parental missed work. When home treatment fails to relieve symptoms, children often seek care in the emergency department (ED) where a limited number of treatment options exist; while largely effective, these rescue treatments currently all require needle insertion of an intravenous line, take time to administer, result in prolonged ED stays, and have potential unpleasant side effects. In adult patients, a number of studies suggest that lidocaine, a local anesthetic administered intranasally, may provide relief of migraine and migraine-like headache pain in minutes. This approach has the benefit of working quickly, not requiring a needle, and having fewer side effects as the medication acts locally on nerves in the nose. Intranasal lidocaine has not yet been studied in children for this purpose. This study will compare the use of intranasal lidocaine to placebo. The goal of this pilot study is to provide information to inform the sample size calculation for the definitive randomized controlled trial that will aim to measure the efficacy of intranasal lidocaine as an analgesic option for children age 7 years and older who present to the Pediatric ED with a chief complaint of migraine or post traumatic headache with migraine-like features. Secondary objectives will be to report on the frequency and severity of rebound headache between the two treatment groups, adverse events of the study drug, as well as the impact on healthcare utilization measures.The investigators hypothesize that children receiving intranasal lidocaine will have faster and more effective pain recovery compared to children receiving placebo and will be less likely to require the standard therapy for migraine headache. Given very few side effects reported in adult studies and the relatively benign nature of those reported, the investigators do not expect any major safety concerns in the study. It is also hypothesized that intranasal lidocaine will lead to shorter ED visits, thus reducing use of staff and hospital resources and saving money for the healthcare system as a whole.

Inclusion Criteria:

1. Children aged 7-16 years

2. Migraine headache fulfilling Irma's criteria:

   • Headache lasting 1-72 hours with at least 4 out of 6 of the following features:

     • Moderate to severe episode of impaired daily activities
     • Focal localization of headache
     • Pulsatile description
     • Nausea or vomiting or abdominal pain
     • Photophobia, phonophobia, or avoidance of light and noise, or
     • Symptoms increasing with activity or resolving by rest.

   OR:

3. Post-traumatic headache as per ICHD-3 (beta edition) definition with migraine-like features (see above):

   A) Any headache fulfilling criteria C and D

   B) Traumatic injury to the head has occurred

   C) Headache is reported to have developed within 7 days after one of the following:

   i. The injury to the head, ii. Regaining of consciousness following the injury to the head, iii. Discontinuation of medication(s) that impair ability to sense or report headache following the injury to the head

   D) Headache persists for > 3 months after the injury to the head

   E) Not better accounted for by another ICHD-3 diagnosis

4. Verbal report of a pain score of 4 or greater on a 10 point numeric pain score (range 0-10 with increasing severity, i.e. 0 = no pain and 10 = most severe pain) after receiving first line therapy (non-narcotic analgesia) in either the out-patient or PED setting

5. Normal vital signs for age

6. Normal neurological exam (no focal deficits or abnormalities)

Exclusion Criteria:

1. Families not providing informed consent or assent, where appropriate
2. History of acute trauma or seizure in the preceding 24 hours
3. Clinical suspicion of or known intracranial pathology or underlying central nervous system disease
4. Headache associated with fever or meningismus
5. Known allergy/sensitivity to lidocaine