Papular urticaria and things that bite in the night.

Whether we are hiking in the back country or playing in our backyard, we run the risk of exposure to offending arthropods. Papular urticaria is a very common hypersensitivity reaction to the bites, stings, and contact with critters such as mites, ticks, spiders, fleas, mosquitoes, midges, flies, and even caterpillars. Children seem to be at greatest risk, although adults are also vulnerable. The classic presentation of papular urticaria includes recurrent pruritic papules or vesicles and varying degrees of local edema. Severity is often related to the host response to the salivary or contactant proteins. Our understanding of the immune mechanism continues to improve; however, our approach to therapy has remained essentially unchanged. Although this review admittedly reaches beyond papular urticaria, it is with the intention of improving the reader's recognition of the offending arthropods, the characteristics of reactions, and the current therapeutic approaches.