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

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