Ice cream headache

Ice cream headache
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.
Classification and external resources
Specialty	neurology
ICD-10	G44.8021 (ICD-10NA)

An ice-cream headache, also known as brain freeze, cold-stimulus headache, trigeminal headache^[1][2] or its given scientific name sphenopalatine ganglioneuralgia (meaning "pain of the sphenopalatine ganglion"), is a form of brief 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, and is believed to result from a nerve response causing rapid constriction and swelling of blood vessels^[3] or a "referring" of pain from the roof of the mouth to the head.^[4][5] The rate of intake for cold foods has been studied as a contributing factor.^[6][7] Ice-cream headache is distinct from dentin hypersensitivity, a type of pain that can occur under similar circumstances.

Cats and other animals^[8] have been observed experiencing a similar reaction when presented with a similar stimulus.

The term ice-cream headache has been in use since at least January 31, 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.^[9]

Cause and frequency

An ice cream headache is the direct result of the rapid cooling and rewarming of the capillaries in the sinuses leading to periods of vasoconstriction and vasodilation. 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.^[10]

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.^[11]

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. Other causes that may mimic the sensation of ice-cream headache include that produced when high speed drilling is performed through the inner table of the skull in people undergoing such a procedure in an awake or sedated state.

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.^[12]

Relief

To relieve pain, some doctors suggest pressing the tongue against the roof of the mouth to warm the area,^[13] tilting the head back for 20 seconds, or drinking something warmer than whatever caused the headache. Some people report relief from breathing in through the mouth and out through the nose, thus passing warm air through the nasal passages.

Research

The phenomenon is common enough to have been the subject of research published in the British Medical Journal and Scientific American.^[10][11] A study conducted by Maya Kaczorowski 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). However, Kaczorowski was ultimately not able to draw a clear connection between the speed of consumption and incidence of sphenopalatine ganglioneuralgia.^[14]

References

External links

• "Ice cream evoked headaches (ICE-H) study: randomised trial of accelerated versus cautious ice cream eating regimen" BMJ 2002; 325 doi: http://dx.doi.org/10.1136/bmj.325.7378.1445 (Published 21 December 2002)