Headache classification: criticism and suggestions

The International Classification of Headache Disorders 2nd Edition (ICHD-II), published in 2004, marks an unquestionable progress from the preceding 1988 edition, but the in-depth analysis it offers is not immune from drawbacks and shortcomings. First of all, it is still basically a classification of attacks and not of syndromes. For the migraine group, while the revised classification more accurately characterises migraine with aura, it fails to provide a sufficiently structured description of those forms of migraine without aura that over the years evolve to so-called daily chronic forms. These forms are not adequately recognised as chronic migraine, which ICHD-II includes among the complications of migraine. The inclusion of short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) in the cluster headache group is bound to generate some perplexity, while the recognition of new daily persistent headache (NDPH) included in the group of other primary headaches as a separate clinical entity appears somewhat premature. Doubts are also raised by the actual existence of triptan-overuse headache, which ICHD-II includes in Group 8 among medication-overuse headaches. Finally, the addition of headache attributed to psychiatric disorder, which is certainly a good option in perspective, is not yet supported by an adequate systematisation.