Unilateral headaches and their relationship with cervicogenic headache.

The concept of headache originating/starting in the neck is revised and considered in the light of previous descriptions of syndromes and entities and with reference to the current diagnostic systems for the classification of headache and other head pain. Cervicogenic headache (CEH), a clinical picture recently described by Sjaastad and coworkers and listed in the International Association for the Study of Pain (IASP) Classification, is analyzed, also taking into consideration its diagnostic criteria in terms of sensitivity and specificity. The problem of a differential diagnosis with migraine, tension headache and other well defined forms of unilateral headaches is discussed with reference to a case series of 114 patients who were selected based on their adherence to two fundamental criteria: (i) side-locked unilaterality of pain; and (ii) pain starting in the neck and spreading to the fronto-orbital area. Based on the results, these simple criteria can contribute to a preliminary identification of possible CEH cases that may then undergo a sequence of clinical and instrumental procedures in order to confirm the diagnosis and, possibly, to localize the level(s) of dysfunction in the cervical spine which may be the target for therapeutic investigations, whether invasive or non-invasive.