I don’t talk about Slurpees enough in this space, and that’s a crying shame. But this week I am grateful to get an opportunity to write about frozen drinks and their discontents, including the sudden, stabbing headache known as “brain freeze.”
Very cold things cause us pain; this much is painfully self-apparent. The ice cube test remains one of the hallmarks of pain tolerance testing for precisely this reason.
But frozen drinks can confer a different kind of pain – intense and fleeting, gone as quickly as it occurs. Despite what you may have grown up believing, your brain isn’t actually freezing in any literal sense. The culprit is your trigeminal nerve, which relays a number of sinus and facial pain symptoms:
Thus, when you drink a Slurpee, the blood vessels near the back of your throat first rapidly constrict from the coldness and then dilate when the blood vessels become warmer again. The dilating blood vessels then pull the tissues around the vessels and the brain such as the meninges, triggering the trigeminal nerve (otherwise known as the fifth nerve), which innervates much of your face, including your forehead.
It’s a painful condition, of course, but generally not a dangerous one unless you plan on downing a bathtub of electric blue slush on a regular basis.
But if you experience pain related to the fifth nerve in your daily life, or in a chronic way that outlasts any specific beverage or experience, that’s an indication that it’s time to visit your expert ENTs right away.