Chronic tension-type headache, which is included in the International Headache Classification, is present in only a minority of patients who present with chronic daily headache. The majority have what is termed transformed migraine, with a history of distinct episodes of migraine in the initial years which progresses into chronic daily headache. These patients with transformed migraine exhibit mixed features of migraine and chronic tension-type headache. Two distinct types of transformed migraine are identifiable, namely those related to excessive intake of medications (drug-induced transformed migraine) and those unrelated to excessive use of medications. The clinical features of transformed migraine and the drug-induced variety are described. The need for revision of the International Classification to include chronic daily headache and the subtypes of transformed migraine is pointed out.
Transformed migraine. Publishing Authors By Initials
