‘Chronic migraine’ is a misnomer

Dear Editor:

Chronic migraine has been addressed from many different perspectives given its high frequency and substantial degree of associated disability. Its diagnostic criteria have been revised according to the successive updates of the International Classification of Headache Disorders; the most recent version is the ICHD-3 beta.¹ These criteria enable accurate selection of patients for epidemiology studies, clinical trials, and for appropriate prescription of recently approved treatments, such as botulinum toxin type A.

Although there is consensus on the definition of chronic migraine (headache occurring on 15 or more days per month for more than 3 months, with features of migraine on at least 8 days per month), we feel that the Spanish term (migraña crónica) is misleading. The dictionary of the Royal Spanish Academy² defines crónico (‘chronic’) as an adjective describing a disease that is long-standing or habitual. We are positive that the term migraña crónica is a literal translation of the English ‘chronic migraine’. In English-language dictionaries, ‘chronic’ is defined as lasting for a long period of time or marked by frequent recurrences.³ This concept of recurrence is lacking in the Spanish term.³ The original adjective ‘chronic’ thus refers to diseases that recur and last for long periods, and these features define migraine accurately.⁴ Seen in this light, the adjective in Spanish does not specify a type of migraine but rather simply emphasises an intrinsic feature of migraine.

In fact, osteoarthritis, diabetes mellitus, and hypertension, to name a few, are also long-lasting disorders. However, to the best of our knowledge, these disorders are not referred to as chronic. Migraña crónica is a pleonasm, a figure of speech in which the adjective emphasises the features inherent to the noun, such as ‘white snow’ or ‘black coal’.

This term has taken the place of other inappropriate and imprecise terms, such as transformed migraine, that were commonly used before the ICHD-3 was published. We understand that the term migraña crónica does not seek to be linguistically attractive but rather to emphasize the duration, recurrence, and severity of this disorder. However, these features are defined and quantified in the diagnostic criteria. According to logic, the name should convey the idea of exacerbation of the symptoms of an already chronic disorder.

In our view, ‘exacerbation’ or ‘worsening of migraine’ would be more appropriate terms. From a nosological viewpoint, chronic migraine is not that different from a hypertensive crisis, an acute episode of decompensated diabetes, or a bout of arthritic pain, although these episodes may last less time. There must be many other terms for this type of migraine which would more accurately reflect its nature, that is, symptom exacerbation in addition to chronicity.

However, this term is already well established and will therefore be very difficult to change. Unfortunately, migraña crónica is not a neologism; neologisms usually become accepted with time, especially in scientific settings. Rather, we find ourselves reinforcing a sort of false friend that should, at the very least, be unmasked.