Hymenoptera:
These are the main insects implicated in allergy to insect stings.
In their natural environment, bees are calm and only sting when they feel they are threatened or when their net is disturbed. When a bee stings, it dies because part of its digestive tract is expelled with its stinger. In their natural habitat, wasps are aggressive, especially in the fall when food is rare. In wasps, the stinger is not systematically lost and a wasp can thus sting several times.
The reaction caused may be local and of a non-allergic nature: symptoms observed consist of swelling and pruritus; they regress rapidly and are caused by venom. A reaction may be local and of an allergic nature: a painful red swelling appears more or less extended which disappears after a day or two. Lastly, a reaction may be systemic with various symptoms: urticaria, edema, acute episode of asthma, anaphylactic shock, vomiting, diarrhea or rhinitis.
Horseflies and Mosquitoes:
Allergic reactions caused by the sting of horseflies or mosquitoes are local reactions. Such reaction may be treated with low-strength topical steroids as well as H1 antihistamines which have a protective effect against these reactions.
If you want to learn more about Insect venom hypersensitivity, read the brochure Insect venom hypersensitivity.