Serum beta-endorphin increase after intravenous histamine treatment of chronic daily headache.

Histamine is able to induce spontaneous-like headache attacks in migraine and cluster headache subjects. Therefore, it has been considered as a possible agent in the pathogenesis of headache. Histamine desensitization is used for the treatment of cluster and other chronic headaches like migrains with interparoxysmal headache. However, it is unknown whether desensitization plays a role in headache improvement. Since a disfunction of the opioid system has been considered responsible for idiopathic headache and since low beta-endorphin levels have been demonstrated in some idiopathic headaches, particularly in migraine with interparoxysmal headache, we planned this study to verify if histamine therapy is able to modify serum beta-endorphin concentrations. For this purpose, we studied 24 healthy control subjects and 36 patients suffering from migraine with interparoxysmal headache refractory to conventional therapies. Patients showed baseline serum beta-endorphin levels significantly lower than healthy control subjects and treatment with histamine for 15 days increased their beta-endorphin concentrations. We believe that histamine treatment can activate the opioid endogenous system. However, the therapeutic effect of histamine remains to be verified by evaluating the correlation between beta-endorphin levels and headache improvement.