What are spider bites?
Most spider bites are harmless, cause minor symptoms, and go away on their own. In North America, there are two types of poisonous spiders whose bites may cause more serious symptoms—the brown recluse spider and the black widow spider.
The black widow spider is all black with a red hourglass on its back. It is also shiny.
A bite from either of these types of spiders requires emergency medical treatment.
Signs of a spider bite
Most bites from spiders cause:
However, brown recluse spider bites also cause:
- White and red bullseye around the bite
- A blue or purple center of bite
- Black blister
- Joint pain
- Stiff joints
Black widow spider bites can cause:
- Strong muscle cramps that show up within 8 hours of the bite
- A hard-to-find bite
- Stomach pain
- Stiff belly
- Difficulty breathing
Causes of spider bites
Spider bites are caused by venomous spiders. There are more than 50 spiders in the U.S. that bite but are not harmful.
When to see a doctor for a spider bite
If you suspect the spider that bit you or someone else was a brown recluse or a black widow, seek medical attention right away.
Otherwise, see the doctor for a spider bite if you have:
Diagnosis/tests for spider bites
To diagnose brown recluse and black widow spider bites, it is most helpful if you saw the spider. However, that is not always possible.
Doctors usually diagnose spider bites based on examining the bite and reviewing your symptoms. In some cases, a spider expert may help with the diagnosis.
Treatment for spider bites
Prevention for spider bites includes cleaning cobwebs out of the places spiders enjoy like:
Wear long sleeves and long pants when in these locations to reduce the risk of a spider bite. Keep firewood outside the house to keep spiders out. Shake out items that have been in storage before using them. Make noise before going into places where spiders like to live to scare them away before you get there.
You can treat most spider bites at home. First, wash the bite with soap and water to prevent infection. Use an icepack to help with pain or swelling.
Brown recluse spider bites
Treatment for brown recluse bites includes managing symptoms. Doctors may give antihistamines for extreme swelling. They may also prescribe antibiotics to avoid infection. Some brown recluse bites require surgery if the bite is especially deep. If you get a brown recluse bite, you'll also receive a tetanus booster.
Black widow spider bites
There is an antivenom for serious black widow bites, but doctors only use it if you have trouble breathing. Otherwise, they treat muscle cramps with muscle relaxers and treat the intense pain with prescription pain medication.
Skin Problems and Treatments Resources
Health Solutions From Our Sponsors
Mayo Clinic: "Spider bites."
Medline Plus: "Spider Bites."
Poison Control: "Black Widow Spider Bites Can Be Dangerous."
Poison Control: "Brown Recluse Spider Bites."
Seattle Children's Hospital: "Spider Bite."
Stanford Children's Health: "Spider Bites."