The Asthma Center

Which insects cause allergy

An insect bite can result in an allergic reaction, skin irritation or in some cases, an infection. When insects bite human skin (like mosquitoes, fleas, stable flies, black flies and lice but not ordinary house flies) their saliva or body produces severe reactions by contact with the skin.

Stinging insects, on the other hand (like bees, wasps, yellow jackets and hornets), actually inject venom into the skin of their victims. In sensitive individuals (estimated to be about 0.4 - 0.5% of the U.S. population), such insect stings may cause sudden allergic reactions. Although most reactions are of a mild to moderate degree, some reactions are severe and on rare occasions fatalities have been reported. In fact it is estimated that between 40 to 100 people in the United States die each year from insect sting reactions. Therefore knowledge about insect sting reactions, insect avoidance and treatment may help in avoiding and/or managing potentially serious reactions.

The HYMENOPTERA class of insects are the only stinging insects. However only a few of the hymenoptera (honeybees, wasps, hornets, yellow jackets and fire ants) cause serious allergic reactions. Overall, the yellow jacket is the most common offender followed by honey bees, wasp and then hornets. Bumblebees rarely sting humans. The base of the stinger of hymenoptera insects is attached to a small venom filled sac. Most stinging insects except the honeybees can reuse their stingers, inflicting multiple venom injections. In contrast, the honeybee's stinger is barbed so when it tries to remove its stinger from the skin, both the stinger and venom sacs are torn off and left in the victim. Most hymenoptera actually use their stingers in self defense, for defense of the hive or for killing other insects.

Africanized honey bees (known as “Killer Bees”) are a tropical variety of honeybees imported from Africa into Brazil in 1956 to increase honey production. They invaded the southwestern United States (Texas, Arizona, New Mexico and California) in 1990 and have been migrating northward 200 to 300 miles each year. These bees are much more aggressive and may swarm individuals even over long distances inflicting multiple stings (8-10 times more than other honey bees) in defense of their hives. They warrant greater caution if encountered. Their presence in our area is still limited.

The imported fire ant (Solenopsis invieta, black and red) is another venomous insect known to cause severe allergy reactions. It gets its name from the intense burning and itching at the site of the sting. Fire ants were first accidentally introduced to Mobile, Alabama in the 1930s from South America and now are found in over twelve states ranging from the south Atlantic seaboard, southern and southwestern United States (25%). Severe allergy reactions (anaphylaxis) have been reported from 0.6 to 16% of those stung with more than 80 deaths reported. While this insect is presently not found in the northeastern United States, it is spreading northward at about 120 miles per year.