For some patients who come to the emergency department for treatment of a migraine headache, peripheral headache nerve blocks (PHNB) have proven to be an efficient and effective treatment for headache relief. Previous studies have demonstrated that adding steroids as an adjunct treatment to standard migraine treatment can reduce recurrence of headaches in the subsequent few days.

Previous studies have provided evidence that administering steroids in addition to standard migraine headache treatment in the emergency department may reduce the recurrence of the headache within 24-72 hours. The standard migraine treatments in previous studies have been varied and include 5-HT receptor agonists, dopamine antagonists, dihydroergotamine, NSAIDS, and opioid analgesics. The steroids added to the standard treatment have been prednisone and dexamethasone (both IV and oral).

This is the first study to examine the combination of peripheral nerve block as the primary treatment of migraine followed by oral dexamethasone to prevent recurrence.

Inclusion Criteria:

• Meet ICHD-3 Migraine Headache Criteria
• Had a minimum 5-point reduction in headache intensity after nerve block(s) or post- block pain score of 0 to 2
• Nerve block performed with bupivacaine 0.5%

Exclusion Criteria:

• Head trauma
• Suspicion of secondary headache (i.e. stroke, known tumor, glaucoma)
• Headache in the setting of viral syndrome
• Chronically on steroids
• Known allergy to dexamethasone
• Unable to reach the patient by phone or text for follow-up
• Gestational diabetes or other uncontrolled diabetes
• Known to be immunocompromised

study drug pills (dexamethasone or placebo) will be placed in identical colored capsules and then into numbered packets. Only pharmacist will be unblinded.