We all scream after ice cream (or at least one third of us do)

What's the most common cause of head pain (as in headache)? A recent Editorial in the British Medical Journal (an Open Access journal, which means anyone can read it for free and without a registration!) notes that lots of things can cause headache, including sex (what do you say, "not tonight, dear, it will give me a headache"?). But the most frequent cause (one third of a random sample) was ice cream ("brain freeze").

The pain begins a few seconds after the rapid ingestion of cold foods or beverages and peaks in 30-60 seconds. The pain is usually located in the midfrontal area, but can be unilateral in the temporal, frontal, or retro-orbital region. It is a stabbing or aching type of pain that recedes 10-20 seconds after its onset. Rarely, it persists for two to five minutes.

RO Smith, writing in the Handbook of Clinical Neurology (Vol. 5) in 1968, reported some courageous self-experimentation on the matter. When he applied crushed ice to one side of his palate he got head pain on that side, and if in the midline he got pain on both sides. But it only occurred in hot weather, never in the winter. Effects on blood vessels (first contracting and then widening) have been invoked to explain this. Migraines are also thought related to blood vessel effects in the head, although there is conflicting evidence whether people who get ice cream headaches are more or less likely to have migraines.

Ice cream headache is almost always transient and self-limiting. While sufferers rarely seek medical attention for the condition, there is a flourishing industry of folk remedies, at least judging from the Letters section of the BMJ.

This information is to show that we at Effect Measure understand there are other problems in the world besides bird flu. And because it's Saturday.