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Will Nothing Stop That Infernal Itch?

By Jennifer Huget
Special to The Washington Post
Tuesday, July 31, 2007

Some people say banana peels do the trick. Others swear by butter, nail polish or a hair dryer turned on high and aimed at the invasion site. And then there's you, ogling a shelf-full of various drugstore potions and rub-ons, each with a different active ingredient and all claiming to relieve the infernal itching of bug bites.

You can't be blamed for wondering, at the height of mosquito season: Does any of this stuff work?

To a degree -- some of it does. Two dermatologists gave us the buzz on bite remedies. Try not to scratch too much as you read.

Know Thy Enemy Mosquitoes don't just suck your blood (which the females need for reproductive purposes); they also deposit a protein that keeps it from coagulating as they drink. As in many allergic reactions, your body responds by releasing histamines to try to fight off the foreign matter. It's the histamines that make the bite site swell into a hard red bump and itch. (That bump's called a wheal, by the way.) When you scratch, says Nathaniel Beers, medical director of the children's health center at Children's Hospital in the District, you start a vicious cycle: Scratching releases more histamines, which make the itching worse.

So why are you itching while those around you are just fine? It's not that you're such a special taste treat to the little bloodsuckers. Some people's allergic reactions to mosquito saliva are simply stronger than others, says Nanette Silverberg, director of pediatric dermatology at St. Luke's-Roosevelt Hospital Center in New York.

Your companion might get bitten and hardly notice, while you're riddled with red welts and itching like mad. An individual's reaction can change over time and with repeated exposure, Silverberg says. And, she notes, your body might respond differently to the spit of different mosquito species found in various locales.

Option 1: Wait It Out Depending on how strong your allergic response is, you'll generally start feeling a bite's itch within a few minutes or a few hours. Most bites stop itching within 24 to 48 hours, Silverberg says.

Of those hours, the ones that will be most excruciating are those when you're trying to fall asleep.

Why do bug bites itch so much more then?

They don't. Silverberg and Beers agree that the sensation of increased itchiness is merely a function of your being less busy, less distracted as you try to relax into slumber.

"That's the case with all medical conditions that itch," Silverberg explains.

Option 2: Trust to Science Seems like everybody's got a home remedy for treating bug bites. Some of them: Apply ammonia, vinegar or baking soda; rub it with basil or soap or -- even, so it's claimed -- Preparation H. For more, see, for example, http://tipnut.com/over-40-mosquito-bite-itch-relief-tips.

But ask a doctor, and he or she will send you to the store. While some well-known commercial preparations contain ammonia or eucalyptus oil or the plant product cardiospermum, a better bet to block those itch-causing histamines is, well, an antihistamine, Beers suggests.

Benadryl (or a generic version, so long as it contains diphenhydramine) can be taken orally or applied topically (in products such as Caladryl), he says.

But, he advises, to treat a kid's bites, stick with the oral kind so you know exactly how much you're using. Letting kids smear on their own ointment can lead to over-application; there have been occasional reports of overdose, Beers says.

The other top treatment, according to the docs, is hydrocortisone cream, which decreases inflammation and lessens the itch. Available generically or in such brands as Cortizone, this topical treatment should be used only if the skin's not broken, Beers says.

Silverberg says hydrocortisone has a "broader anti-inflammatory effect" than antihistamines. (She thinks antihistamines do more to help you relax and fall asleep than actually to relieve the itch.)

Those with especially robust allergic responses may find over-the-counter hydrocortisone doesn't do the trick and should ask the doctor for a prescription for a higher-concentration cream.

As for that old standby, calamine lotion, Beers says it's a drying agent and thus not really good for anti-itch. Silverberg is a tad more generous. The stuff is somewhat soothing, he says, plus the pink color will psychologically mollify any itch.

Option 3: Dig Deeper Remember that vicious cycle of scratching that Beers described? Don't tell the kids, but that incessant scratching might eventually lead to some relief.

"If you keep going at it until you create an open lesion, [the bite] feels better because you've given the irritant a mode of exit," Beers explains. But, he adds, "I'm not sure I'd recommend that."

(If you do scratch a bite open, make sure to keep your fingernails short and clean and apply an antibiotic cream such as Neosporin to ward off infection, Beers suggests.)

As for most home remedies -- from applying ice to the bite to coating it with a paste of baking soda and water -- there's not much supporting science. Still, Silverberg allows, they might have "some soothing effects on itching and a mild anti-inflammatory effect."

As for ice, Beers says it's "not going to stop the [allergic] reaction completely, but it can temporize it" by restricting blood flow to the site.

Roll-on antiperspirant? Maybe. Silverberg says the aluminum chloride it contains helps "coagulate the cut" and hastens the healing process. As with many home remedies, Beers notes, "most antiperspirants cause some vasoconstriction"; constricting blood vessels could dampen the allergic response.

Garlic? While studies have yet to show that eating it keeps bugs at bay, Silverberg says rubbing a cut clove on an open lesion -- such as an over-scratched mosquito bite -- may confer garlic's "antiviral, antibacterial and anti-inflammatory" benefits.

Rub only once, she cautions: Overuse can cause blistering. ยท

Jennifer Huget is a regular contributor to the Health section. Comments:health@washpost.com.

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