Chronic Primary Headaches ( headaches without known disease processes ) are defined to be headaches occuring > 15 days a month, lasting > 30 minutes, for > 3 to 6 months. 90 % are Tension type headache, and most of the other 10 % are Migraine. Migraine is supposed to be unilateral, pulsating in quality, moderate to severe in pain intensity, aggrevated by physical activity, and accompanied by nausea/ vomitting, or photophobia or phonophobia. Aura happens 20 % of migraines. Tension Type Headache, which in the past had been thought to originate from muscle contractions of pain sensitive parts around cranium, are now hypothesized to be mainly due to hyperexcitable central nociceptive neurons in trigeminal nucleus, thalamus, and cortex as well as increased muscle and skin pain sensitivity. The diagnostic criteria for Tension type headache is tight, nonpulsatile quality of pain, mild to moderate in intensity, and bilateral in location, and not aggrevated by activities. However, in reality, many tension headaches have Throbbing, Pulsatile quality ( one can feel the increased pulsations of temporal arteries in front of the anterior ear lobes with throbbing pain), sometimes superimposed on the dull achy character. Neurologist termed this hybrid headache " Tension-Migraine ", which is common if one inquires the symptom characters carefully. Also, tension headache is a misnomer, because it implies that the headache is related to mainly emotional stress or depression, when in fact in most instances, the aggregating factors are simple overwork or unknown. Ironically Medicare classifies tension type headache under a disease category of mental disorder.
Whether the headache is Migraine or Tension type or a Hybrid, eastern herbal medicine does not distinguish them, but has classified more than 10 major syndromes causing chronic headache, based on the differentiation of symptoms and observation of physical signs.