Table 2 Diagnostic criteria for transformed migraine by Silberstein et al. [13]

A. Daily or almost daily (>15 days/month) head pain for >1 month

B. Average headache duration of >4 h day (if untreated)

C. At least 1 of the following:

 1. History of episodic migraine meeting any HIS criteria 1.1–1.6

 2. History of increasing headache frequency with decreasing severity of migrainous features over at least 3 months

 3. Headache at some time meets HIS migraine criteria 1.1–1.6 other than duration

D. Does not meet criteria for new daily persistent headache or hemicrania continua

E. At least 1 of the following:

 1. There is no suggestion of one of the disorders listed in groups 5–11

 2. Such a disorder is suggested, but it is ruled out by appropriate investigations

 3. Such a disorder is present, but first migraine attacks do not occur in close temporal relation to the disorder