Spider bites: First aid

Most spider bites cause only minor injury. A few spiders can be dangerous. In the United States, these include the black widow spider and the brown recluse spider.

Seek emergency care immediately if:

  • You were bitten by a black widow or brown recluse spider
  • You are unsure whether the bite was from a poisonous spider
  • You have severe pain, abdominal cramping or a growing ulcer at the bite site
  • The person who was bitten isn't breathing

To take care of a spider bite:

  • Clean the wound. Use mild soap and water and apply an antibiotic ointment.
  • Apply a cool compress. Use a cloth dampened with cold water or filled with ice. This helps reduce pain and swelling. If the bite is on an arm or leg, elevate it.
  • Take an over-the-counter pain medication if needed. If the wound is itchy, an antihistamine (Benadryl, Chlor-Trimeton, others) may help.

Your doctor may recommend a tetanus booster shot if you haven't had one in the last five years.

Black widow spider

You can usually identify a black widow spider by the hourglass marking on its belly. In the United States, this spider is more common in the South.

Signs and symptoms of a black widow spider bite may include:

  • At first, slight swelling and faint red marks
  • Intense pain and stiffness
  • Severe abdominal pain or cramping
  • Chills, fever and nausea
Black widow spider

The black widow spider is known for the red hourglass marking on its belly.

Brown recluse spider

The brown recluse spider has a violin-shaped marking on its back, but this mark can be hard to see. In the United States, its range is central and southern states.

Signs and symptoms of a brown recluse spider bite vary but may include:

  • At first, a mild pain
  • Redness and intense pain
  • A deep blue or purple area around the bite, which may develop a red ring around it
Brown recluse spider

The brown recluse spider is known for the violin-shaped marking on its top.

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