Allodynia as a complication of migraine: background and management.

Allodynia is a normal part of the untreated migraine attack in most people with episodic migraine and is prevalent in chronic migraine. The extent to which allo-dynia contributes to the pain and disability of migraine attacks is unclear, as is its clinical importance. The presence of allodynia correlates with the severity and other features of migraine, including aura, migraine-associated symptoms, and motor symptoms. The development of allodynia is associated with resistance to triptan treatment. It is uncertain whether this treatment resistance is due to the accompanying increase in headache severity or whether the development of allo-dynia is the fundamental biologic event causing the new treatment-refractory state. Animal models support the relationship to allodynia. Intravenous ketorolac may be effective at treating migraine with allodynia several hours after the development of the throbbing pain, but prior treatment with opioid analgesics may confer treatment resistance. Occipital nerve blocks rapidly treat migraine pain and allodynia. Uncontrolled studies have successfully used dihydroergotamine to treat episodic and chronic migraine with allodynia.