Our Guide to Poisonous Spiders in the U.S.

Author: Mosquito Squad

Most spiders within America are harmless, but there are two renowned spiders whose bites are dangerous. These two spiders are the brown recluse and the black widow. Although it’s common to have a healthy fear of spiders, spiders only bite if they feel threatened. Wouldn’t you protect yourself if someone came towards you that look larger than life? 

When to Worry About a Spider Bite 

Spider bites are known to become swollen in the area of the bite. However, there are other, less well-known signs of when a spider bite has an effect on the body that is cause for concern. 

Brown Recluse 

This all-brown spider is found in closets, barns attics, and other shaded areas waiting for prey to come near. Brown recluse spider bites feel mild, but the sting leaves behind a severe pain and local redness that usually develops within eight hours or more after the bite. Some brown recluse spider bites may include a purple or blue area around the bite, which is surrounded by a whitish ring and a large outer ring in a bull’s eye pattern.  

A fluid blister then forms at the spider bite site, and then sloughs off, revealing a deep ulcer that may turn black. In the worst-case scenarios, a brown recluse ulcer could forced victims to amputate a limb. Other signs and symptoms of a black widow or brown recluse spider bite may include abdominal or joint pain, fever, nausea, and headache. 

Locations where you can find the brown recluse: 

  • Missouri 
  • Tennessee 
  • Kansas 
  • Arkansas 
  • Louisiana 
  • Oklahoma 
  • Eastern Texas 

Black Widow 

The black widow is an insect known by its black body and red hourglass shape found on its back. Bite symptoms are immediate pain, burning, redness, and swelling. Other signs and symptoms of a black widow spider bite are a feeling of a pinprick, and sometimes double fang marks where the spider bit.  

Locations where you can find the Black Widow: 

  • Western Canada 
  • The Pacific Northwest of the United States 
  • Mexico  
  • Southeast Canada 
  • North Florida 

Things to Look for After a Spider Bite 

An allergic reaction to a spider bite will happen almost immediately after the venom has gotten into the bloodstream.

Toxic reaction to a spider bite can reveal itself in various ways: 

  • Nausea, vomiting 
  • Diarrhea 
  • Fever 
  • Weakness 
  • Lightheadedness 
  • Rapid swelling at the site of the bite 
  • Muscle spasms 
  • Headache 
  • Drowsiness 
  • Fainting  
  • Red streaks leading from the bite 
  • Pus draining from the bite or sting 
  • A fever 
  • Increased pain 

If you experience any of these symptoms, immediately consult a doctor. In the meantime, contact your local Mosquito Squad and ask about their add-on services for spider control. 

For more information, check out our previous blog on knowing the difference between a mosquito bite and a spider bite