Is it safe to use an insect repellent on your kids — or yourself — that contains DEET? And are there any safe and effective alternatives?
I began asking these questions in the early 90s when we had our first child. In those days, we summered on Long Island where Lyme disease was prevalent. Information on bug spray safety was scarce and we were scared to use it on our daughter. But we were also scared of her contracting the disease. So instead of using a bug repellent, we would check her obsessively for ticks after outings, knowing there was a 24-hour grace period before the ticks did their damage.
Today, West Nile virus is a danger as well — both in town and country. And the bug removal trick doesn’t work with virus-carrying mosquitoes. Once you’ve been bitten, there is no recourse.
So I have researched the bug repellent questions again and consulted with Dr. Gina Solomon, a senior scientist at the Natural Resources Defense Council and a public health doctor. The answers are still not definitive, but much clearer now.
There are three bug-repelling ingredients approved by the Environmental Protection Agency and recommended for use by the Centers for Disease Control:
- Oil of lemon eucalyptus or PMD
In tests, all have proven effective and long-lasting against a variety of insects and ticks, including those that carry West Nile virus and Lyme disease. Of the three, DEET appears to be effective against the widest range of bugs — a consideration if you are traveling to tropical regions. If you are planning such a trip, find out what bug-borne diseases you may be exposed to and which repellents work best against them.
Another effective ingredient that is relatively long-lasting is soy oil, but it has not yet made it onto the CDC list.
Most other natural alternatives, such as citronella, are too short-lasting to be practical in most situations.
DEET may have short-term side effects in some people — rashes, other skin reactions and wooziness. If you or your child has any such reactions, stop using DEET. The side effects should go away. Seizures have been reported in a very small number of cases. Dr. Solomon says DEET lowers the seizure threshold. While it is not likely to cause seizures in healthy people, it could trigger a seizure in someone with an underlying propensity, or in a child with a fever. So, if your child has a temperature, play it safe and steer clear of DEET.
Another concern with DEET, which has recently been shown to be a neurotoxin, is that it appears to amplify the toxic effects of other chemicals to which people may be exposed — such as 2,4-D, a toxic weed-killer commonly used on lawns. It may also have long-term effects not yet identified.
Picaridin is much milder on the skin than DEET and is nearly odorless. It has a long history of safe usage in Europe and was recently approved for use in the U.S. Put another way, this ingredient seems like it might be safer than DEET, though it may not protect against as wide a variety of bugs.
Oil of lemon eucalyptus may also be safer than DEET. However, it can irritate the eyes and is not recommended for children under three.
Different products have different concentrations of the active ingredient (DEET, Picaridin or oil of lemon eucalyptus). Higher concentrations are not more effective but do provide longer-lasting protection to a point, after which there is no added benefit but possibly higher risk.
For DEET-based products, choose concentrations of 5-10% for an hour or two outdoors and up to 30% for an all-day outing (~8 hours). Do not exceed 30% with children — the American Academy of Pediatrics warns against it — and avoid DEET altogether on infants under 2 months. Some researchers advise against DEET throughout infancy.
Dr. Solomon recommends that adults, too, use products with no more than 30% DEET, the legal limit in Canada. Research has shown there is no added benefit to DEET concentrations above 50%.
With Picaridin, use a 20% formulation for all-day outings, and a lower concentration for shorter jaunts.
Oil of lemon eucalyptus is shorter-lasting than DEET and Picaridin. A 40% concentration should last around 6 hours.
For more information, see my June 2010 This Green Life column, Bug Spray, Examined. To receive my monthly column by email, subscribe for free. To look up products based on the active ingredient, use this nifty EPA tool (halfway down the page).