The cause of the sudden appearance of headache in patients is considered to be the following: 1. If the patient has hypertensive disease, the headache may be caused by a sudden rise in blood pressure, and the type of headache is mainly manifested as head swelling and pain, which can be clarified by the examination of blood pressure measurement. 2. If the patient has a previous history of migraine, neuropathic headache, cluster headache, and the headache suddenly occurs, it is considered to be caused by these headaches. If the headache is severe, with severe pain, accompanied by nausea, vomiting or inflexible limb movement, the patient should seek medical advice. 4.Patients with sudden onset of headache may also be caused by cold or fever, so pay attention to whether the patient is accompanied by muscle aches and pains or elevated body temperature.