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.

What Are the Signs & Symptoms of a Spider Bite?

Of a brown recluse spider bite:

• swelling or redness around the bite
• pain around the bite within 2 to 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

Of a black widow spider bite:

• 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

Of an allergic reaction:

• 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, call the National Poison Control Center at 1-800-222-1222. 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.

How Do I Treat a Spider Bite?

If your child has a spider bite:

• Wash the area with soap and water.
• Put an ice pack 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.

Get Medical Care Right Away for a Spider Bite if:

• Your child has any signs of an allergic reaction.
• Your child develops any kind of rash after a bite.
• Your child has severe pain or cramping.
• The area begins to look infected (increasing redness, pain, swelling, warmth, or pus).
• You think your child was bitten by a brown recluse spider or black widow spider. Even without symptoms, have your child seen right away. Early treatment can help ease symptoms.

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.