5. An antivenin is available for Cenfruroides sculpturatus.
6. Keep the victim under observation and be prepared to give symptomatic supportive care.
Figure 4-66.Black widow and brown recluse spiders and scorpion.
Spiders in the United States are generally harmless, with several exceptions. The most notable are the black widow and brown recluse spiders. Their bites are serious but rarely fatal.
The female black widow spider is usually identified by the hourglass-shaped red spot on its belly (fig. 4-66). Its bite causes a dull, numbing pain, which gradually spreads from the region of the bite to the muscles of the entire torso. The pain becomes severe, and a board-like rigidity of the abdominal muscles is common. Nausea, vomiting, headache, dizziness, difficulty in breathing, edema, rash, hypertension, and anxiety are frequently present. The bite site can be very hard to locate, since there is little or no swelling at the site, and the victim may not be immediately aware of having been bitten. The buttocks and genitalia should be carefully examined for a bite site if the suspected victim has recently used an outside latrine. The following first aid treatment steps are suggested:
1. Place ice over the bite to reduce pain.
2. Hospitalize victims who are under 16 or over 65 for observation.
3. Be prepared to give antivenin in severe cases.
The brown recluse spider (fig. 4-66) is identified by its violin-shaped marking. Its bite may initially go unnoticed, but after several hours a bleb develops over the site, and rings of erythema begin to surround the bleb. Other symptoms include skin rash, fever and chills, nausea and vomiting, and pain. A progressively enlarging necrotic ulcerating lesion eventually develops. Treatment for brown recluse spider bites includes the following:
1. Early diagnosis is important since, within the first 8 hours, a medical officer has the option of excising the lesion and starting corticosteroid therapy.
2. The lesion should be debrided, cleansed with peroxide, and soaked with Burows solution three times daily.
3. Apply polymyxin-bacitracin-neomycin ointment, and cover the lesion with a sterile dressing.
Poisonous snakes are found throughout the world, primarily in the tropical and temperate regions. Within the United States, there are 20 species of poisonous snakes. They can be grouped into two families, the Crotalidae (rattlesnakes, copperheads, and moccasins) and the Elapidae (coral snakes).
The Crotalidae are called pit vipers because of the small, deep pits between the nostrils and the eyes (fig. 4-67). They have two long hollow fangs, which normally are folded against the roof of the mouth, but which can be extended by a swivel mechanism when they strike. Other identifying features include thick bodies, slitlike pupils of the eyes, and flat triangular heads. Further identification is provided by examining the wound for signs of fang entry in the bite pattern shown in figure 4-67. Individual identifying characteristics include audible rattles on the tails of most rattlesnakes, and the cotton white interior of the mouths of moccasins. These snakes are found in every state except Maine, Alaska, and Hawaii.
Coral snakes are related to the cobra, kraits, and mamba snakes in other areas of the world (fig. 4-68). Corals, which are found in the