Graf J, Ingwersen J, Lepka K, et al. - In this single-center retrospective chart review study, researchers identified possible risk factors affecting the incidence of intravenous immunoglobulin (IVIg) treatment-related cephalalgia in neurological diseases. This investigation was performed at the Department of Neurology, Heinrich Heine University hospital in Düsseldorf, Germany. The study sample consisted of neurological patients receiving IVIg treatment between July 13, 2017, and August 14, 2017. After IVIg infusion (n = 22 infusions), headache patients showed a decreased heart rate, but no important difference in blood pressure. Compared with patients with headache after IVIg infusion, patients without headache after IVIg infusion (n = 69 infusions) displayed a higher systolic blood pressure increase and a stronger reduction in the heart rate. In patients who developed a headache after IVIg infusion, the infusion rate was significantly slower and age significantly lower. Possible explanations are a reaction to immunoglobulin aggregates, stabilizers, or vasoactive mediators. The lack of a body temperature connection does not suggest a systemic immune response as a cause of headache.