Hypnic Headache
Hypnic headache is a rare primary headache disorder. Its most unique feature is that it ONLY develops during sleep and awakens the patient, which is why it is also called an “alarm clock” headache.
People with new or never evaluated hypnic headache should be carefully evaluated by their physician for the following:
Make sure there is no underlying secondary cause of the headache. Some examples include intracranial disorder causing high intracranial pressure, sleep apnea, nocturnal high blood pressure, nocturnal low blood sugar, and medication withdrawal (i.e. a headache comes when pain medication wears off overnight); or To make sure that there is no other primary headache disorder that could mimic hypnic headache. Examples of primary headache disorders that can be caused by sleep include cluster headache and migraine headache.
Hypnic headaches are frequent (occurring more than 10 days per month) headaches that occur only during sleep. The headache lasts between 15 minutes and 4 hours after waking up. Usually hypnic headaches start in people after the age of 50, but they can also occur in younger people. The pain can range from mild to severe and is usually bilateral (on both sides of the head). Sometimes people can describe migraine-like symptoms, including nausea, with hypnic headaches.