How to identify and treat common bites and stings

In contrast, the body of a black widow spider is black; females exhibit a distinctive red or yellow hourglass marking on their ventral aspect.^28,31 The pinprick sensation of a bite leads to symptoms that can include erythema, swelling, pain, stiffness, chills, fever, nausea, and stomach pain.^30,32

A bee sting is more likely to lead to a severe allergic reaction than a wasp sting.

Management. Again, see “Providing relief and advanced care” on page E6. Consider providing antivenin treatment for moderate or severe bites of brown recluse and black widow spiders.

Fleas

Fleas are members of the order Siphonaptera. They are small (1.5-3.2 mm long), reddish brown, wingless, blood-sucking insects with long legs that allow them to jump far (12 or 13 inches) and high (6 or 7 inches).³³ Domesticated cats and dogs are the source of most flea infestations, resulting in an increased risk of exposure for humans.^34,35 Flea bites, which generally occur on lower extremities, develop into a small, erythematous papule with a halo (FIGURE 4) and associated mild edema, and cause intense pruritus 30 minutes after the bite.^35-37

Fleas are a vector for severe microbial infections, including bartonellosis, bubonic plague, cat-flea typhus, murine typhus, cat-scratch disease, rickettsial disease, and tularemia. Tungiasis is an inflammatory burrowing flea infestation—not a secondary infection for which the flea is a vector.^34,35

Preventive management. Repellents, including products that contain DEET (N,N-diethyl-meta-toluamide), picaridin (2-[2-hydroxyethyl]-1-piperidinecarboxylic acid 1-methylpropyl ester), and PMD (p-menthane-3,8-diol, a chemical constituent of Eucalyptus citriodora oil) can be used to prevent flea bites in humans.^33,38 Studies show that the scent of other botanic oils, including lavender, cedarwood, and peppermint, can also help prevent infestation by fleas; however, these compounds are not as effective as traditional insect repellents.^33,38

Flea control is difficult, requiring a multimodal approach to treating the infested animal and its environment.³⁹ Treatment of the infested domestic animal is the primary method of preventing human bites. Nonpesticidal control involves frequent cleaning of carpeting, furniture, animal bedding, and kennels. Insecticides can be applied throughout the house to combat severe infestation.^33,38

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