Spider Bite, Brown Recluse

Description

Local or systemic illness caused by brown recluse spider bite envenomation

Etiology

• Brown recluse spider (also known as the fiddleback spider) features:
  • Appearance:
    • Delicate body and legs spanning 10–25 mm
    • Tan- to dark-brown with darker violin-shaped marking visible on the upper aspect of the head
    • 3 pairs of eyes
  • Found widely throughout the south-central part of the U.S.
  • Habitat: Typically warm and dry locations, indoors or outdoors such as wood piles, bundles of rags, cellars, under rocks, or in attics
  • Bites are typically defensive
• Mechanism of toxicity:
  • Venom is a complex cocktail of enzymes and peptides that:
    • Binds to RBC and causes hemolysis
    • Causes prostaglandin release and activates complement cascade
    • Causes lipolysis and tissue necrosis
    • Triggers platelet aggregation and thrombosis
    • Triggers allergic response to venom antigenic properties
    • May lead to shock and DIC in rare cases
  • Toxicity proportional to:
    • The amount of venom relative to the size of patient
    • Location of envenomation on the body

• Children are more vulnerable to a given amount of venom than healthy adults
• Fatality more common in children due to severe intravascular hemolysis