The most effective insect repellent contain Deet (diethyltoluamide). Repellents do not actually repel flies and mosquitoes. They simply fog their radar. Mosquitoes are guided to their victims by the sensations of moisture, warmth and carbon dioxide – exactly the qualities people exude while exercising or working outdoors on a hot, humid day.

Repellent sprays or lotions give off fumes which block the bugs’ sensory pores on their antennae. So as bugs approach you, they get confused and hover out of striking range. Sounds great. Except for two problems. While repellents turn off biting insects, they attract some bees and stinging insects.

And more people may be more sensitive to the chemicals in repellents than they are to mosquito bites themselves. To get around those problems, some doctors recommend taking tablets of thiamine (a B vitamin) as an internal insect repellent.

It seems that when we consume large quantities of thiamine, some is excreted in our perspiration, creating an odor that repulses bugs (human can’t smell it). In addition, you can wear light colored clothing (such as khaki or tennis whites), with long pants and sleeves to expose as little skin as possible. Put up good screens.

Discourage mosquitoes from breeding by eliminating, filling or draining watery areas around your house: rain barrels, old cans and tires, stagnant puddles, ditches, hollow trees and stumps, and marshy ground. Install an electronic bug zapper near you porch or outdoor activity area. Or buy nontoxic insect traps.

Will You React?

The question most people ask about insect allergy are: how do I know if I’m allergic to insect sting? How can I tell if my child is allergic to them? No one experiences a life threatening reaction the first time they're stung. A severe local reaction, however – exaggerated swelling, nausea, weakness and so forth – is almost a certain harbinger of potential and more severe systemic reactions.

And as is the case with other types of allergy, whether or not you ever experience that ominous first reaction depends on a number of factors:

What bit you. Anyone who is allergic to bees is apt to be allergic to wasps, yellow jackets, hornets and ants. However, the potency of insect venom varies from species to species, so some can cause more of a problem for you than others.

The amount of venom. Naturally, the more venom injected, the more chance for a reaction. And more stings mean more venom. But venom levels can also vary for other reason. In the early spring and late fall, for instance, honeybees carry around far less venom than they do at the peak of summer.

Other allergy. Nearly one third of people who are allergic to insects are allergic to drugs, especially drugs that are injected, like penicillin. Other than that, coexisting allergy doesn’t seem to have much bearing on susceptibility to insect stings.

Your general state of health. Although it has no bearing on whether or not you’re allergic to insects in the first place, your general state of health may influence how well you tolerate a sting or bite. If you’re ever had a run in with any insect that resulted in anything more than a slight swelling, you should be on your guard against future encounters. And you should tell your doctor all the details.

Don't be macho – mild reactions are the best clues for predicting life threatening reactions and shouldn’t be played down. The information can save your life. Your doctor will also need to know what bit you.

The problem is, most of us don't know one insect from another and assume anything that stings is simply a bee. So if you possibly can, take the insect’s body to the doctor with you, even if it's squashed. Lacking a body as evidence, some doctors stock photos of common stinging and biting insects – sort of like mug shots to help identify criminals.