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Overview

What Are Spider Bites?

Spider bites happen when a spider bites someone’s skin. Most spider bites don't go all the way through skin, so they usually cause only mild reactions. But a bite from a black widow spider or brown recluse spider can cause serious reactions and needs medical care right away. Allergic reactions to spider bites can happen but are rare.

Signs & Symptoms

What Are the Signs & Symptoms of a Spider Bite?

The signs and symptoms of a spider bite depend on the type of spider and whether the person has a spider bite allergy.

Brown Recluse Spider Bites

  • swelling or redness around the bite
  • pain around the bite within 2–8 hours
  • blisters around the bite
  • rarely, chills, fever, nausea, rash, body aches, and dark urine (pee)
  • some bites can become dark in the center

Black Widow Spider Bites

  • either no visible bite or very mild pain at the bite
  • painful muscle cramps starting a few hours after the bite
  • a firm and painful belly
  • nausea and vomiting
  • shakiness and weakness
  • sweating
  • headache
  • rarely, trouble breathing

Allergic Reactions to Spider Bites 

  • swelling of the face or mouth
  • trouble swallowing or speaking
  • chest tightness, wheezing, or trouble breathing

If someone in your family might have a bite from a brown recluse spider or black widow spider, visit the National Poison Control Center online or call 800-222-1222. Because spider bites contain venom, which is a type of poison, poison control is an expert resource. It's available for free, 24 hours a day.

Prevention

What Can Help Prevent Spider Bites?

  • Be careful in garages and attics and around woodpiles. Make sure they are free of spider webs.
  • Wear gloves when gardening, cleaning out the garage, or working in outdoor spaces such as woodpiles.
  • Dress kids in long sleeves and pants when they're active around garages, attics, woodpiles, etc.
  • Keep firewood outside the house to avoid bringing spiders inside.
  • Shake out shoes and gardening gloves stored in a garage, shed, basement, attic, or mudroom before putting them on.

Treatment & Care

How is a Spider Bite Treated?

If your child has been bitten by a spider:

  • Wash the area with soap and water.
  • Put an ice pack wrapped in a thin towel or a cool wet cloth on the bite area to relieve pain and swelling.
  • Watch for redness, swelling, or other signs of the bite getting worse or infected.
  • Call the doctor to make sure your child is up to date on their tetanus vaccine.

When Should I Get Medical Care Right Away?

If you think your child was bitten by a brown recluse spider or black widow spider, see a doctor right away even if there are no symptoms. Early treatment can help ease symptoms.

Also call the doctor if your child:

  • has any signs of an allergic reaction
  • develops any kind of rash after a bite
  • has severe pain or cramping
  • develops signs of an infection (increasing redness, pain, swelling, warmth, or pus)
Date reviewed: June 2023