|Classification and external resources|
The trigeminal nerve, shown in yellow, conducts signals from dilating blood vessels in the palate to the brain, which interprets the pain as coming from the forehead.
An ice-cream headache, also known as brain freeze, cold-stimulus headache, or its given scientific name sphenopalatine ganglioneuralgia (meaning "nerve pain of the sphenopalatine ganglion"), is a form of brief cranial pain or headache commonly associated with consumption (particularly quick consumption) of cold beverages or foods such as ice cream and ice pops. It is caused by having something cold touch the roof of the mouth (palate), and is believed to result from a nerve response causing rapid constriction and swelling of blood vessels or a "referring" of pain from the roof of the mouth to the head. The rate of intake for cold foods has been studied as a contributing factor. There are people who cannot experience "brain freeze" or similar symptoms.
The term ice-cream headache has been in use since at least 31 January 1937, contained in a journal entry by Rebecca Timbres published in the 1939 book We didn't ask Utopia: a Quaker family in Soviet Russia. The first published use of the term brain freeze, as it pertains to cold-induced headaches, was on 27 May 1991.
Cause and frequency 
"Ice cream headaches" result from quickly eating or drinking very cold substances. It is commonly experienced when applying ice-cream (or similar) to the roof of the mouth (palate) or when swallowing it. Typically, the headache appears in about 10 seconds and lasts about 20 seconds, though some people experience much longer lapses of pain; the pain seems to relate to the same side of the head, as the cold substance was applied to the palate, or to both sides of the head in the case of swallowing. The most effective way to prevent it is to consume the cold food or liquid at a slower rate. Keeping it in one's mouth long enough for the palate to become used to the temperature is also an effective preventative.
An ice cream headache is the direct result of the rapid cooling and rewarming of the capillaries in the sinuses. A similar but painless blood vessel response causes the face to appear "flushed" after being outside on a cold day. In both instances, the cold temperature causes the capillaries in the sinuses to constrict and then experience extreme rebound dilation as they warm up again.
In the palate, this dilation is sensed by nearby pain receptors, which then send signals back to the brain via the trigeminal nerve, one of the major nerves of the facial area. This nerve also senses facial pain, so as the neural signals are conducted the brain interprets the pain as coming from the forehead—the same "referred pain" phenomenon seen in heart attacks. Brain-freeze pain may last from a few seconds to a few minutes. Research suggests that the same vascular mechanism and nerve implicated in "brain freeze" cause the aura (sensory disturbance) and pulsatile (throbbing pain) phases of migraines.
It is possible to suffer from an ice-cream headache in both hot and cold weather, because the effect relies upon the temperature of the food being consumed rather than that of the environment.
Anterior cerebral artery theory 
Another theory into the cause of ice-cream headaches is explained by increased blood flow to the brain through the anterior cerebral artery, which supplies oxygenated blood to most medial portions of the frontal lobes and superior medial parietal lobes. This increase in blood volume and resulting increase in size in this artery is thought to bring on the pain associated with an ice-cream headache.
When the anterior cerebral artery constricts, reining in the response to this increased blood volume, the pain disappears. The dilation, then quick constriction, of this blood vessel may be a type of self-defense for the brain.
This inflow of blood cannot be cleared as quickly as it is coming in during the ice-cream headache, so the blood flow could raise the pressure inside the skull and induce pain that way. As the intracranial pressure and temperature in the brain rise the blood vessel contracts, and the pressure in the brain is reduced before reaching dangerous levels.
To relieve pain, some doctors suggest pressing the tongue against the roof of the mouth to warm the area or tilting the head back for about 10 seconds. Another method to relieve ice cream headaches is to drink a liquid that has a higher temperature than the substance that caused the ice cream headache. Some people report relief by breathing in through the mouth and out through the nose, thus passing warm air through the nasal passages.
The phenomenon is common enough to have been the subject of research published in the British Medical Journal and Scientific American. What is likely the most comprehensive research on the subject to date, Maya Kaczorowski, 12, of Ontario, conducted human testing from December 2001 to January 2002. Though the results demonstrated a higher incidence of sphenopalatine ganglioneuralgia in subjects consuming the ice cream sample in less than 30 seconds vs. those who consumed slowly, with no time limit (27.3% and 12.5% respectively), Kaczorowski was ultimately not able to draw a clear connection between the speed of consumption and incidence of sphenopalatine ganglioneuralgia.
The International Classification of Headache Disorders (ICHD) code is 13.11.2 and International Statistical Classification of Diseases and Related Health Problems ICD-10NA code is G44.8021, "Headache attributed to ingestion or inhalation of a cold stimulus".
- Jankelowitz, SK.; Zagami, AS. (Dec 2001). "Cold-stimulus headache.". Cephalalgia 21 (10): 1002. doi:10.1046/j.1468-2982.2001.00301.x. PMID 11843876.
- How stuff works
- Mayo clinic (causation)
- Ice cream evoked headaches ICE-H study
- University of Guelph
- Timbres, Harry; Timbres, Rebecca (1939). "We didn't ask Utopia: a Quaker family in Soviet Russia". Prentice Hall. Retrieved 2013-02-19. "But your nose and fingertips get quite numb, though, and if you don't keep rubbing your forehead, you get what we used to call "an ice cream headache.""
- "Confessions of a City Literate". New Hampshire Union Leader. 27 May 1991. Note: the earliest recorded use of the term "brain freeze" (with a different meaning) was in 1968 in a Canadian academic journal.
- Bird, N; MacGregor, EA; Wilkinson, MI (January 1993). "Ice cream headache—site, duration, and relationship to migraine". Headache 32 (1): 35–8. doi:10.1111/j.1526-4610.1992.hed3201035.x. PMID 1555929.
- Scientific American Mind, 1555–2284, 2008, Vol. 19, Issue 1. "Brain Freeze." Andrews, Mark A., Lake Erie College of Osteopathic Medicine.
- http://bmj.bmjjournals.com/cgi/content/full/314/7091/1364 Ice cream headache — Hulihan 314 (7091): 1364 – BMJ
- Welsh, Jennifer (22 April, 2012). "Cause of Brain Freeze Revealed". TechMediaNetwork.com. Retrieved 2012-04-24.
- Salemi, Vicki (June 2009). "Body Oddities Explained". AOL Health. Retrieved June 2009.
- Gordon, Serena (February 2003). "The Scoop on Ice-Cream Headaches". Current Science 88 (13): 12.
- "ICHD-II Abbreviated pocket version" (pdf). International Headache Society. 2004. Retrieved 2009-03-25.
- "Ice cream evoked headaches (ICE-H) study: randomised trial of accelerated versus cautious ice cream eating regimen"