A rare type of headache affecting people over 50
What is hypnic headache?
Hypnic headache syndrome is a rare primary headache disorder which usually affects people over 50, although it can start from the age of 40 onwards. There has been little research into the condition compared to some other headache and migraine disorders.
What are the symptoms?
Hypnic headaches occur exclusively at night, waking you from your sleep at the same time, usually between 1 and 3 am. Indeed this condition has the nick name “alarm clock headache”.
The pain can be unilateral (on one side of the head) or bilateral (on both sides of the head). Some people describe the pain as throbbing although not everyone experiences this. The pain begins abruptly and can last from 15 minutes to 6 hours, although typically it is about 30-60 minutes. It is more common amongst women than men. The pain in rare instances is associated with autonomic features (such as a blocked nose or watering eyes), photophobia (light sensitivity) and phonophobia (sound sensitivity).
If you have hypnic headache you should be able to go back to sleep when the pain subsides, although you may experience more than one attack per night. You may experience 15 or more attacks per month. In a study by DW Dodick, four patients were found to have experienced this condition when falling asleep during the day.
Study of hypnic headache
Hypnic headache was first described in 1988 in a journal article by N H Raskin who looked at patients aged between 67 and 84 years old. Some research has now been completed on the links between hypnic headache and REM sleep.
Most of the patients described in the research literature are reported to have had other types of headaches before their diagnosis of hypnic headache was established.
To establish if you have hypnic headache, you will need to see your doctor who will need to take a full history of your sleep patterns and night time habits (including snoring and restlessness). This helps to exclude secondary causes of headaches which start at night. These causes include drug withdrawal, sleep apnoea, brain tumours and temporal arteritis (inflammation of the temporal artery). Other primary headaches (such as migraine, cluster headaches and chronic paroxysmal hemicrania) can also wake you at night so these need to be excluded before you can be sure that you have hypnic headache.
For patients with hypnic headache, recommended initial treatment is caffeine (in the form of cups of coffee at bedtime) or indomethacin. Indomethacin would not be safe for patients with history of stomach ulcers. Lithium carbonate is an alternative, but may be poorly tolerated or contraindicated for older adult patients. Also, patients on lithium would need regular blood tests to check if the blood levels of lithium are within safe limits. If you cannot tolerate lithium, your doctor may suggest alternative treatments including flunarizine. These are taken prophylactically at bedtime.