What is a brown recluse spider?
Brown recluse, violin, or fiddleback (Loxosceles), spiders are about
0.5 in. (1.3 cm) 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 that may be 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 (ulcer) 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). Signs and symptoms include:
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
- Do not apply a tourniquet. It may cause more harm than
- Try to positively identify the spider or catch it to
confirm its type.
A brown recluse bite can be serious and may require immediate
medical care. Call a doctor if:
- You have severe symptoms throughout your
- An open sore and necrosis develop. Necrosis is black, dead
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
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
- Cause 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).
Hyperbaric oxygen therapy may also be used for tissue damage from a spider bite.
Medicines that may be used include: