Children and older people are especially vulnerable to the adverse effects of sunscreen and insect repellent when used together.
Sunscreen is vital in protecting from the harmful UV rays of the sun. Insect repellent is also important in avoiding exposure to mosquitoes, which can carry West Nile virus. But try to avoid using them both together.

Researchers at the University of Manitoba, Canada, have found that oxobenzone, a sunscreen agent, and DEET, the main ingredient of insect repellent, increase one another's absorption through skin if used together. They are meant to stay on the skin's surface. We know that DEET can cause skin allergy, low blood pressure, headaches and even swelling of the brain if absorbed.

The team say the older people, with their thinner skin, and children, who tend to have a larger body surface area relative to adults, are more vulnerable to these effects. They are working on modifying the non-active ingredients in sunscreen and insect repellent to make them absorbed less easily through the skin.