The sweating anomaly in cluster headache. Further observations on the underlying mechanism.

We describe a patient with a typical history of cluster headache for more than 18 years. During the first approximately 10 years of his disease, the pain was right-sided, and pupillometric and evaporimetric measurements indicated a sympathetic deficiency on this same side. However, for the next greater than 6 years, his pain was consistently left-sided, although the signs of sympathetic dysfunction still were more marked on the right side. This was also true for the findings obtained during the interictal period and for the heating test performed within an attack. The implications of this interesting case are discussed. The view that two separate lines of symptom production lead to the pain and the autonomic phenomena seems to be supported by this case history. The cluster headache syndrome may also be a bilateral disorder, with only the weight of balance pointing one way or the other. Finally, the autonomic test results of this patient could reflect an autonomic "scar" in the previous headache side.