What mainstream medicine says about DEET

[Guest guest]

AUGUST 6, 2001 VOL. 158 NO. 5

PERSONAL TIME/YOUR HEALTH

To Deet or Not to Deet?

It's summertime, and the mosquitoes are hungry. How to keep the most

effective sprays from making you sick

BY IAN K. SMITH, M.D.

If April showers bring May flowers, what pops up when it rains through most

of May and June as well? A bumper crop of mosquitoes, as communities from

Texas to New Jersey have learned only too well this summer. The best reason

to avoid being skeeter bait is, as always, the sheer human misery of dealing

with all those itchy red welts. But this summer there's also the chance,

admittedly small, of more serious consequences, especially now that the West

Nile virus is spreading up and down the Eastern seaboard.

Last week the U.S. Centers for Disease Control and Prevention urged

Americans to help reduce the risk even further by taking a few simple

precautions, such as wearing insect repellent and eliminating sources of

standing water where mosquitoes breed. But before you throw your favorite

bug spray into a backpack and head out the door, it's important to keep a

few safety tips in mind.

The most effective insect repellents contain a powerful chemical called DEET

(or N, N-diethyl-meta-toluamide), developed for the U.S. military in the

1940s. DEET-based repellents last longer against mosquitoes and other biting

bugs, including those that transmit Lyme disease, than the so-called natural

bug sprays, which usually contain various plant oils. Since the chemical is

absorbed readily into the skin, it's always best to apply any DEET products

sparingly. Common side effects include rash, swelling, itching and eye

irritation--usually a result of rubbing the eyes with hands that have been

sprayed.

In rare cases, DEET has been linked to more serious complications like

slurred speech, confusion and seizures. In most of those instances, the

amount of repellent used was unusual. (In one case, a 3 1/2 year-old girl's

body, bedding and pajamas were sprayed each night for two weeks.) And that

brings up an important point: children are perhaps most vulnerable to the

accidental misapplication of bug spray.

As a precaution, the American Academy of Pediatrics recommends that

repellents used on youngsters contain no more than 10% DEET. Keep the

chemical out of young mouths and eyes by applying it yourself. Lotions often

work best in this respect. Remember that like perfume or cologne, a thin

layer will do the trick.

Also consider wearing pants and long-sleeve shirts to minimize the amount of

exposed skin, especially in dark, damp areas that are particularly thick

with mosquitoes. For those worried about damaging their clothes, it's a good

idea to spray a small area of material first to make sure it's DEET-proof

before applying repellent to sleeves or cuffs.

Finally, when you or your children come back inside from the great outdoors,

make sure all of you wash your hands and any areas that came in contact with

the repellent. DEET products can be safe and effective as long as you follow

instructions and don't overuse them.

Dr. Ian appears on NBC's Today show. ianmedical@...