Red, White and Blue? – Think Recluse Spider Bite

The brown recluse spider bite, initially a small, red lesion, is often not noticed at first or recalled as a mild sting or burning sensation. While most heal without treatment, in some cases necrotic tissue damage occurs and in a few, serious systemic illness (fever, hemolysis, and thromobocytopenia) ensues.

Typically, the bite site is itchy, painful and red within 6 to 12 hours. The onset of tissue necrosis appears as a mottled, blue-purple center at the site. Red blisters appear, followed by an ischemic (white) ring (due to vasoconstriction) surrounded by redness. Necrosis usually appears within two days. Younger children are more likely than adults to have a systemic reaction.

The reaction is due to enzymes and proteins in the spider venom. One enzyme destroys red blood cells and is thought to damage myelin nerve sheaths, causing a more intense pain sensation as necrosis progresses. Another enzyme (hyaluronidase) increases subcutaneous tissue permeability, allowing the venom to spread around the site. Lipase in the venom creates scarring over areas of fatty tissue.

Treatment for minor, nonprogressive lesions consists of standard cleansing, ice, oral antiinflammatory and antihistamine medications, and may include an updated tetanus vaccine. Preventive antibiotics are indicated at the early signs of necrosis. Treatment for severe lesions is controversial and there is little evidence supporting the use of oral Dapsone (which has significant adverse effects), hyperbaric oxygen, or surgical debridement.

(Zeglin D. Am J Nurs 2005;105(2):64-68)

Comment: With spring approaching in endemic areas, think about the risk for youth working in unoccupied basements or moving boxes in the attic and youngsters playing hide-and-seek around wood piles and rocks where brown recluse spiders sought shelter.  Your students can make spider recognition poster for the health office – these have six eyes set in a distinctive pattern. —J.O.