Why does one of my ears suddenly turn red for no reason?

Who's asking: James Lamb, Virginia Beach, VA

This is actually pretty common among fair-skinned people, and in most cases, it's not a symptom of anything at all. It's the same mechanism as blushing -- involuntary dilation of the blood vessels -- and it happens for much the same reasons: embarrassment, sudden changes in temperature, mild allergic reactions to food or medication, responses to alcohol or caffeine.

No one knows why some people blush more than others, or why some people's ears flush more than others. One theory suggests that it has to do with levels of serotonin in the blood stream, which would explain why facial and ear flushing can be a side effect of some anti-depressant medications. If it gets to the point of being painful, doctors can treat it with Botox, the same way they treat excessive sweating.

Ear flushing can also be a symptom of high blood pressure or acne rosacea, so it's something to mention to your doctor during a routine physical. Anna and I once had a boss whose ears would flush so badly when he was angry that they turned purple; he had learned to control his temper but couldn't control his ears, so they served as a barometer of the emotional weather in the corner office.

This morning I am scrambling to figure out what's wrong with my car. On the way to Newburyport last night, the thermostat indicator light started flashing bright red. The Volkswagen has a closed cooling system, so the fact that the coolant reservoir was low means there's a leak somewhere. I refilled the reservoir and headed for home, to my profound disappointment -- Chuck Hogan was signing The Killing Moon at Jabberwocky Books, and I missed it -- but by the time I got home, the thermostat light was flashing again, and the Check Engine light was on. I'm afraid this is going to be expensive.