Pain pressure threshold in cluster headache patients.

Pain perception threshold (PPT) in the head was assessed with a pressure algometer in 58 cluster headache (CH) patients (52M, 6F; 41 episodic and 17 chronic). Fourteen patients in cluster period were retested in remission. Thresholds were assessed at 10 symmetrical points on each side of the head and at the deltoid. Compared with controls (n = 50), CH patients had lower PPT in the head and in the deltoid. PPT was lower on the symptomatic side than on the non-symptomatic side in patients with episodic CH during a cluster period (p < 0.001) and in patients with chronic CH (p < 0.05). This pattern was more evident during a cluster period than during remission (p < 0.05). A reduced PPT did not correlate with illness duration and pain side. The lowest PPT mean values were found at the anterior and intermediate levels of the temporal muscle on the symptomatic side. These results imply a central mechanism underlying the pathogenesis of CH.