Objective.–To investigate whether there is clinical or biochemical evidence for a transient systemic inflammation during active periods of cluster headache.
Methods.–Twenty-seven male and female consecutively selected patients with episodic cluster headache filled in questionnaires aiming at detecting any concurrent systemic vasculitic or rheumatoid disease. They were physically examined by both a neurologist and a rheumatologist independent of each other. Blood and urine samples were taken one to three times during an active cluster period and once in remission. The following analyses were performed: hemoglobin, erythrocyte sedimentation rate, C-reactive protein, complete blood counts including differential counts, creatinine, albumin, creatine kinase, electrophoreses of serum (with haptoglobin, orosomucoid, IgG, IgM), von Willebrand's factor, antinuclear antibodies, rheumatoid factor, cytoplasmic antineutrophil cytoplasmic autoantibodies, perinuclear antineutrophil cytoplasmic autoantibodies, and routine urinary tests. An age- and sex-matched control group of 99 consecutive patients attending the Outpatient Department of Neurology for symptoms/diseases other than severe headache completed the same questionnaire as the patient group.
Results.–Only one patient with cluster headache showed clinical signs (livedo reticularis) that could have been due to an ongoing systemic vasculitis. Most symptoms were equally or even more prevalent in the control group than among the patients with cluster headache. However, cold feet were about twice as prevalent among female patients with cluster headache than in the control group. This was considered due to their smoking habits. Laboratory tests showed no statistically significant differences between the active cluster periods and remission. There were some slightly abnormal values in single laboratory tests, some of which were probably due to concurrent upper respiratory infections. The findings of laboratory tests for one patient could have been due to nephritis. All patients were negative for cytoplasmic antineutrophil cytoplasmic autoantibodies and perinuclear antineutrophil cytoplasmic autoantibodies.
Conclusions.–These results were taken as evidence that no systemic inflammation is present during the active cluster headache period. However, whether a local retro-orbital inflammation underlies the pathophysiology of cluster headache remains obscure.