ABSTRACT
Allergic reactions to insect bites are much less common than reactions to insect stings. Several studies suggest that severe bite reactions occur about 50 times less commonly than severe sting reactions. Many of the clinical aspects of biting insect allergy have been thoroughly discussed in a 2003 review (1). In this chapter, the main focus will be on which insects are important, the known allergens and salivary components, and the appropriate use of immunotherapy. There are more than 14,000 species from 400 genera of blood-feeding arthropods. The most important hematophagous insects belong to the orders Diptera (flies), Hemiptera (bugs), and Siphonaptera (fleas). Ticks of the order Acarina of the class Arachnida will also be considered, although they are not insects. Many other bugs of the order Hemiptera and some beetles, especially aquatic species, of the order Coleoptera occasionally bite humans, but allergic reactions have not been reported. In addition, many larval forms may bite, but again allergic reactions to these bites are extremely rare. Allergic reactions to bites have been ascribed to other arachnids, but definitive evidence is lacking to demonstrate IgE antibodies against centipede and millipede bites. There probably are rare cases of IgE-mediated allergy to spider bites, but there are no published systematic studies.
