Diagnostic distribution of 100 unilateral, side-locked headaches consulting a specialized clinic.

Objectives: We analyzed the diagnoses of patients consulting due to strictly unilateral headaches. Methods: We prospectively collected data from 100 consecutive patients. Diagnosis followed the ICHD-II criteria. Results: They accounted for 18.9% of the 528 patients seen in the study period. They were more frequent in males (58%). Age ranged from 19 to 81 years. Diagnostic distribution was: cluster headache (38 cases), a variety of secondary headaches (14 cases), migraine (11 cases), cervicogenic headaches (9 cases), hemicrania continua (8 cases), nummular headache (6 cases), psychiatric headache (5 cases), paroxysmal hemicranias (4 cases), short-lasting unilateral neuralgiform headache attacks syndrome (3 cases), stabbing headache (1 case), and hypnic headache (1 case). Mean ages at onset fell between 47 and 58 years for several diagnoses (cervicogenic, nummular, psychiatric, hemicrania continua and paroxysmal hemicrania headaches), and were 22 years for migraine, 32 for cluster and in general older than 55 years for secondary headaches. Conclusions: Strictly unilateral headaches account for almost 20% of headaches in subjects attending a headache clinic. Trigeminal-autonomic cephalgias in general (52%) and cluster headache in particular (38%) are the most frequent diagnoses, but secondary headaches account for 1 of 5 cases. Age at onset can be of help in their presumptive diagnosis.