Increased plasma histamine levels in migraine patients

Whole blood and plasma histamine levels, peripheral basophil and eosinophil counts and serum immunoglobulins have been measured in a group of eighteen patients with migraine in remission and in twelve of these patients during a headache attack. Plasma histamine levels were significantly elevated (P less than 0.0005) in patients with migraine both during headache attacks and symptom-free periods.