Thermographic Studies in Vascular Headache

“AGA Thermovision” has been used to record the temperature of the face and scalp in normal subjects and patients susceptible to vascular headache. Even when free of headache, the latter group showed asymmetry of heat loss from the forehead more often than normal controls. During migraine headache, the skin temperature was lower on the affected side by about 1°C in 8 out of 12 of the patients with hemicrania. The reduction of skin temperature on the side of migraine headache, in spite of dilatation of the extracranial arteries, Indicates that blood Is shunted away from the skin during the attack. Asymmetry of heat loss persisted for some time after the relief of migraine headache by intravenous serotonin or oral ergotamine tartrate therapy, suggesting that these agents achieve their effect through constriction of the extracranial arteries rather than dilatation of skin capillaries. In contrast to migrainous patients, three out of five patients with cluster headache showed an Increase in skin temperature on the painful side in the later part of the attack. In two of these patients, a “cold spot” could be seen over one eye in the early phase of the attack, suggesting that blood flow in the internal carotid artery is diminished at this time. Skin temperature was increased bilaterally by the intramuscular Injection of reserpine and decreased by the intravenous Injection of serotonin. The intracarotld injection of serotonin caused ipsilateral flushing of the face, while constriction of the external carotid artery and its branches, and of the Internal carotid artery, was demonstrated angiographically. No change in skin temperature was registered thermographically.