What are episodic intermittent and chronic migraine?
Episodic migraine is 14 or fewer headache days per month, while chronic migraine is defined as 15 or more headache days (tension type-like and/or migraine-like) per month for 3 months or more having the features of migraine headache on at least 8 days per month.
Chronic migraine, or transformed migraine, is a complication of intermittent migraine, with 2.5% progressing yearly from episodic to chronic migraine. In the United States, 3.2 million people have chronic migraine and 80% are women.
It may occur with or without medication overuse.
The pain is often mild to moderate and not always associated with photophobia, phonophobia, nausea, or vomiting and may resemble a mixture of migraine and tension-type headaches with intermittent severe migraine-type headaches.
Depression is present in 40% and anxiety in 30%.
