Hot Water Just Gets Dry Skin in Hot Water

I don’t mind proclaiming to the world that I have been itching like crazy lately, since it appears that dry weather, and not parasites, have been to blame.

Dr. Kathleen Behr, a UCLA dermatologist, explains that in dry weather, or in overheated houses, the skin dries out. And that puts our itch receptors on red alert, telling us, perhaps, that all’s not right with our skin.

Behr’s advice: Refrain from taking hot baths and showers, and if you bathe, don’t bask for hours, because it strips water-trapping oils from your skin. Heat relieves the itch--ooh! aah! yes!--but only makes it worse in the long run by further drying the skin. Instead, within five minutes of taking a cooler shower, towel-dry lightly, then douse your still-damp body in dry-skin ointment to trap that water. Use a heavier cream if your skin is particularly dry.

I also learned that scientists have been scratching their heads for years over just what an itch really is. Yes folks, it’s been a bonafide scientific mystery, and more than just an academic one.

Some people suffer from something nasty called “therapy-resistant itch” which--as its name implies--is a mysterious itch that doesn’t respond to normal anti-itch medications. (It can develop in people who have kidney or liver disease or who are HIV-infected, among others.) Understanding itching better might bring relief to these folks.

“An itch was for a long time thought to be something quite close to, but not quite, pain,” says David Andrew, a scientist working at the Barrow Neurological Institute in Phoenix. The same nerve cells in the skin were deemed responsible for both sensations. But not so!

One tip-off that itch and pain have different nerves came from the fact that people taking morphine for pain relief often develop nasty itches. (Why would that happen if itching were just a mild form of pain?) And, after a year and half of hard slog, Andrew and colleagues have recently reported (in the journal Nature Neuroscience) that itching is sensed using a totally different set of nerve cells. You can pinch the skin, heat it or cool it--and those nerves do nothing. Induce an itch, however, and zap! They fire.

We also asked Andrew why on earth we were built to itch. What’s the evolutionary advantage of feeling like little creatures are walking all over your skin (which in my case, I reiterate, they were not)?

“We think it developed over the years to cope with fleas and parasites that attack the skin,” Andrew says. “The irritation, the itch, says, ‘Scratch this area; get rid of this thing that’s biting you.’ That could also be why we’re programmed to feel better once we’ve scratched. It feels so much better, doesn’t it?”

Oh yes.

Sleep May Seal In the Day’s Learning

As well as taking too-hot baths, another mistake I make is skimping on sleep. There are columns to be written! Health and medical news to catch up on! (Frivolous TV shows to watch!) Turns out my all-nighters may be counterproductive.

OK, so my mom could have told me that. But now Harvard scientists have shown it, too.

In another report from Nature Neuroscience, researchers had 24 people learn a simple mental task. Some were allowed to sleep the next night; others were made to stay up all night.

A few days later--after everyone was well-rested--all 24 were tested on the task they’d learned. Those who’d slept that first night performed better--as if they’d learned something from the drill. But the night revelers showed no improvement at all.

Maybe, say the scientists, this points a finger at why sleep is important. We need it to sear all we’ve learned during the day into our brain circuits.

So kids: Listen to Mom. She is always right.

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If you have an idea for a topic, write or e-mail Rosie Mestel at Los Angeles Times, 202 W. 1st. St., Los Angeles, CA 90012, rosie.mestel@latimes.com.