FRIDAY, July 2, 2004 (HealthDayNews) -- Mosquito repellents with DEET may cause short- and long-term health effects, says a Duke University Medical Center researcher.
Pharmacologist Mohamed B. Abou-Donia found frequent and prolonged use of DEET, the most often recommended, most effective and most common mosquito repellent ingredient, caused brain cell death and behavioral changes in rats.
The health threat posed by DEET (N,N-diethyl-3-methylbenzamide) to humans is still being studied, but Abou-Donia said his 30 years of research on pesticides' effects on the brain clearly indicate that people need to be cautious about their use of DEET.
He added that children are especially vulnerable to subtle brain changes caused by chemicals in the environment. That's because their skin more readily absorbs such chemicals, which have more of an impact on a child's developing nervous system.
Parents should not use mosquito repellents that contain more than 10 percent DEET on children under age 6, the American Academy of Pediatrics advises. Many heavy-duty repellents have much higher concentrations.
In another study, University of Manitoba scientists found that the rate of DEET absorption into the skin skyrockets when DEET-based repellents are mixed with oxybenzone, a common ingredient in sunscreens. When DEET and oxybenzone are mixed, DEET absorption into the skin increases to 30.2 percent from the normal 9.6 percent. Moreover, people tend to re-apply sunscreen because it washes off, while DEET doesn't; it wears off.
Evidence suggests that when DEET and oxybenzone are used together, there may be an increased risk for stroke, headache and high blood pressure, according to the study, released last summer.
More information
The American Academy of Pediatrics outlines safety precautions you need to take when using DEET on children.
