Skip to content
My WebMD Sign In, Sign Up

Information and Resources

Font Size
A
A
A

Brown recluse spider bite

What is a brown recluse spider?

Brown recluse, violin, or fiddleback (Loxosceles), spiders are about 0.5in long with a dark violin-shaped mark on the combined head and midsection (cephalothorax). They are found most often in the south-central part of the United States and live in hot, dry, abandoned areas, such as wood or rock piles.

See a picture of a brown recluse spider .

What are the symptoms?

Brown recluse spider bites don't always hurt right away. In fact, you may not know that you have been bitten until other symptoms appear. Symptoms of a brown recluse spider bite include:

  • Reddened skin followed by a blister that forms at the bite site.
  • Mild to intense pain and itching for 2 to 8 hours following the bite.
  • An open sore (ulcers) with a breakdown of tissue (necrosis) that develops a week or more following the bite. This may take months to heal.

Some people have a severe, systemic (whole-body) reaction to brown recluse spider bites, including the rapid destruction of red blood cells and anemia (hemolytic anemia). Symptoms include:

  • Fever and chills.
  • Skin rash all over the body with many tiny, flat purple and red spots.
  • Nausea or vomiting.
  • Joint pain.

What should I do if a brown recluse spider bites me?

If you think you have been bitten by a brown recluse spider:

  • Remain calm. Too much excitement or movement will increase the flow of venom into the blood.
  • Apply a cool, wet cloth to the bite or cover the bite with a cloth and apply an ice bag to the bite.
  • Do not apply a tourniquet. It may cause more harm than benefit.
  • Try to positively identify the spider or catch it to confirm its type.

A brown recluse bite can be serious and may require medical care. Call your doctor immediately if:

  • You have severe symptoms throughout your body.
  • An open sore and black, dead tissue (necrosis) develops.

How is a brown recluse spider bite diagnosed?

A brown recluse spider bite is diagnosed through a physical examination and questions about the bite. You should be prepared to describe the spider, where and when the bite took place, and what you were doing at the time. (If you are able to safely capture and transport the spider, bring it with you to show your doctor.) Your doctor will ask what your main symptoms are, when they began, and how they have developed, progressed, or changed since the bite.

How is it treated?

Medicine to counteract brown recluse spider venom is not available in the United States or Canada. Treatment depends on how severe the bite is.

  • For bites that do not develop open sores, treatment includes applying a cold compress, elevating the bite area, and avoiding moving the bite area.
  • If you develop an open sore (ulcer) and dead skin (necrosis), treatment includes removing the dead skin from the sore. This may involve follow-up and replacing the dead skin with new skin (skin grafts).

Medicine that may be used include:

Author Jan Nissl, RN, BS
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Tracy Landauer
Primary Medical Reviewer William M. Green, MD - Emergency Medicine
Specialist Medical Reviewer Sean P. Bush, MD, FACEP - Emergency Medicine and Envenomation Specialist
Last Updated February 1, 2008

WebMD Medical Reference from Healthwise

Last Updated: February 01, 2008
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Hot Topics

Health Solutions From Our Sponsors

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

tea
What you should eat.
Woman sitting in front of UV lights
Is yours working?
woman using breath spray
What's causing yours?
colon xray
Get the facts.
MS Overview
Recognizing symptoms.
bowl of yogurt with heart shape
Eat for a healthy heart.
woman doing pushups
To help you get fit.
Colored x-ray of tooth decay
Know what to look for.
Woman sitting with child
Do you know the symptoms?
fruit drinks
Foods that can help you focus.
Sad dog and guacamole
Don't feed this to your dog.
Thyroid exam
See how much you know.

Women's Health Newsletter

Find out what women really need.