Widow Spider Bite (Latrodectism)


General Comments

  • There are approximately 30 different widow spider species found worldwide

Latrodectus Mactans (Black Widow Spider, Show-Button Spider)

  • Seasonal Prevalence: most black widow bites occur between April-October in the United States
  • Geography
    • Found in USA and Canada (Black Widow is Most Abundant in Southeastern United States)
    • Spider Resides in Dark Spaces, Such as Wood Piles, Rock Piles, Sheds, Garages, and Basements
  • Female Spider (Which are Responsible for Most Significant Human Bites)
    • In Contrast, Male Widow spiders Have Smaller Fangs, Less Venom, and Weaker Biting Muscles
    • Black with 1 cm Body, 5 cm Legspan, and Red Hourglass Mark on Ventral Abdomen
    • Spider is Aggressive and Bites on Slight Provocation: typically when trapped or web is disturbed

Latrodectus Bishopi (Red-Legged Widow Spider)

  • Geography
    • Found in Florida

Other Latrodectus Species

  • Geography
    • Found in Other Temperate and Subtropical Parts of the World

False Black Widow Spiders

  • Steatoda Species (see False Black Widow Spider Bite)
    • May Produce a Similar (But Milder) Presentation (Called “Steatodism”) to that of Widow Spider Bite


Alpha Latrotoxin (Neurotoxin) in Venom<



Clinical Manifestations (Latrodectism)

Widow Spider Bite Site

Cardiovascular Manifestations

Gastrointestinal Manifestations

Hematologic Manifestations

Neurologic Manifestations

Otolaryngologic Manifestations

Pulmonary Manifestations

Renal Manifestations

Other Manifestations


Treatment of Pain at Bite Site

Treatment of Muscle Spasms

Widow Spider Antivenom

Tetanus Prophylaxis