Recluse spiders Recluse spiders, also called fiddle-back spiders, brown spiders , and reapers , include the brown recluse ( Loxosceles reclusa ), Big Bend recluse ( L. blanda ), desert recluse ( L. deserta ), Arizona recluse ( L. arizonica ), Texas recluse ( L. devia ), and Apache recluse ( L. apachea ). Figure 13 Brown Recluse Spider (Loxosceles Reclusa)
Figure 14. Recluse Spider Bite at 15 Minutes
Source: Spencer Greene
Figure 15. Recluse Spider Bite at 20 Hours
Source: Lou Coticchio Unlike widow spiders, recluse spiders are not distributed throughout the continental U.S. These spiders are most commonly found in the South and Midwest, particularly in Tennessee, Arkansas, Texas, Oklahoma, Missouri, and Kansas. 70 On extremely rare occasions, a recluse spider can be found outside of its normal habitat after stowing away in cargo or luggage. Similar to widow spiders, they are shy in nature, and bites typically occur when the victim inadvertently brushes against the spider, which causes it to bite in defense. The moniker “fiddle-back spider” comes from the violin-shaped mark on the dorsal cephalothorax. Recluse spiders also have six eyes organized into three dyads in a semicircle. The spider measures up to 20 mm, and the legs are significantly longer than the body itself. U.S. poison centers received an average of 1,080 calls annually regarding recluse spiders between 2015 and 2017. 1-3 The total number of recluse bites is unknown. Many go unreported, and many lesions attributed to recluse bites are unrelated soft tissue infections. Children younger than age six were implicated in 263 (8.1%) cases. Of all exposures, 438 (13.5%) involved victims younger than age 20. There was one fatality and 40 patients with major effects in the three-year period. Recluse spider venom is complex and contains hyaluronidase, collagenase, esterase, and various nucleases and proteases. Sphingomyelinase-D is unique to recluse spiders and can contribute to both the local tissue necrosis and the systemic hemolysis that characterize recluse spider envenomations. 71
Source: Spencer Greene Recluse spider bites often go unnoticed initially. Not uncommonly, bites occur at night while the patient sleeps. Pain is occasionally present, but typically the bite is not particularly uncomfortable. Over several hours and days, two types of clinical findings may appear. Locally, there will be a central area in which an ulcer and possibly an eschar develop. Surrounding this is a white ring of ischemia, which in turn is surrounded by well-delineated erythema. After several days, there may be some elevation along the margins of the bite site, but there is no significant swelling. There is also no fluctuance or purulent drainage. If these are present, it is likely a soft tissue infection, which is often misdiagnosed. 88 In fact, fewer than 1% of wounds that ED patients claim to be spider bites are actually envenomation. It is important to make the correct diagnosis, because the initial treatments for the two entities are different from each other. Figure 16. Recluse Spider Bite at 4 Days
Source: Spencer Greene
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Book Code: RPTTX2024
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