The insects that most plague us are the mosquito and black fly, very common and annoying. The first exposure triggers no reaction, but after repeated bites and injection of bug saliva, an immediate hypersensitivity develops and a wheal appears within minutes, soon followed by a pruritic papule. Children may experience fairly extensive swelling, especially those under age 3, because of the greater water content of the dermis. This is particularly evident if a bite has occurred around the eye or at the wrist or ankle, or if the child has been the target of several bites concurrently.
Orbital swelling is often confused with periorbital cellulitis, a serious infection, but a cold compress and an oral antihistamine such as diphenhydramine will provide relief and help distinguish between the two. Watch for secondary infection caused by scratching — spreading erythema, purulent discharge or crusting. Infected insect bites may need systemic antibiotic treatment, and in my experience, black flies are the culprit more often than not. Of the stinging insects, we find Hymenoptera apidae (honeybees, bumblebees) and vespidae (yellow jackets, hornets and wasps). Yellow jackets are more aggressive and attracted by human food, so they’re most frequently to blame.
Immediate treatment consists of cold compress and analgesia. In the case of a honeybee, remove the stinger and venom sac left in the skin by scraping with the blade of a knife. Bumblebees rarely bother people, and the stinger stays with the insect. Local reaction to Hymenoptera bites may extend to a diameter of ≥ 10 cm and last for several days. Urticaria and angioedema can develop, and most seriously, anaphylaxis. For the latter two, it’s necessary to immediately administer epinephrine, systemic steroids and antihistamines, and later refer to an allergist for further assessment. If found to be truly allergic, the child will require an automatic adrenaline dispenser, such as an EpiPen or Twinjet.