Histamine inhalation is a specific but insensitive laboratory test for migraine

Migraine is a subjective complaint and no laboratory test has until now been of value. The aim of the present study is to evaluate whether histamine inhalation may be used as a diagnostic test for migraine. In a double-blind study design, 15 migraineurs and 15 control subjects scored headache intensity and characteristics before, during, and in the subsequent 12 h after inhalation of increasing doses of histamine (0, 2, 4, 8, 16, 32 and 64 mg/ml). During the histamine inhalations, headaches increased dose-dependently in both groups. Eleven of the migraineurs and eight of the healthy controls experienced headaches after the inhalations. These headaches fulfilled the IHS criteria for migraine without aura in six of the migraineurs, but in none of the control subjects. Using this as a test parameter, the specificity of the test was 1, but the sensitivity was only 0.4. Our results indicate that histamine inhalation is a specific but insensitive laboratory test for migraine. Migraineurs should be informed about the risk of a migraine attack being provoked before histamine inhalation in pulmonary laboratories.