Spider Bite

Main Symptoms

  • Bite from a spider seen on the skin
  • Onset of bite symptoms (redness, pain, swelling) and a spider is seen in close proximity

Types of Spider Bites

  1. Black Widow Spider Bite
    • A shiny, jet-black spider with long legs (total size 1 inch)
    • A red (or orange) hourglass-shaped marking on its under-side
    • Causes immediate local mild pain, swelling and occasionally 2 fang marks
    • Severe muscle cramps are present by 1 to 6 hours, and last 24 to 48 hours.
    • Rarely causes death (exception: bitten by several spiders or small child is bitten)
    • Note: many are dry bites because the fangs are small
  2. Brown Recluse Spider Bite
    • A brown spider with long legs (total size 1/2 inch)
    • A dark violin-shaped marking on top of its head
    • Causes local pain and delayed blister formation in 4 to 8 hours
    • The center becomes bluish and depressed (crater-like) over 2 to 3 days.
    • Skin damage may require skin grafting in 10% of cases
    • Systemic symptoms such as fever, vomiting, myalgias can occur (but no life-threatening symptoms)
  3. Nondangerous Spider Bites
    • More than 50 spiders in the U.S. have venom and can cause local, nonserious reactions.
    • The bites are painful and mildly swollen for 1 or 2 days (much like a bee sting).
    • Most single, unexplained, tender bites that occur during the night are due to spiders.

See More Appropriate Topic

Call 911 Now (your child may need an ambulance) If

  • Difficulty breathing or swallowing

Call Your Doctor Now (night or day) If

    • Your child looks or acts very sick
    • Any black widow spider bite
FIRST AID for Black Widow Spider Bites: Apply an ice cube or ice pack to the bite for 20 minutes to reduce the spread of the venom (no tourniquet)
  • Abdominal pain, chest tightness or other muscle cramps
  • Bite pain is severe
  • Bite looks infected (red streaking from the bite area, yellow drainage) (Note: infection doesn’t start until at least 24-48 hours after the bite. Any redness in the first 24 hours is due to venom)

Call Your Doctor Within 24 Hours (between 9 and 4) If

  • You think your child needs to be seen
  • Bite pain persists > 2 days
  • NOTE: Since brown recluse spiders are hard to identify, bring the spider along in a jar

Call Your Doctor During Weekday Office Hours If

  • You have other questions or concerns

Parent Care at Home

  • Nonserious spider bite and you don’t think your child needs to be seen

Home Care Advice for Nondangerous Spider Bites

  1. Cleansing: Wash the bite thoroughly with soap and water
  2. Meat Tenderizer: Rub the bite area with a cotton ball soaked in a meat tenderizer solution for 20 minutes. (Exception: avoid if near the eye.) If not available, apply an ice cube for 20 minutes
  3. Pain Medicine: Give acetaminophen or ibuprofen as needed for pain
  4. Expected Course: Some swelling and pain for 1 to 2 days. It shouldn’t be any worse than a bee sting
  5. Call Your Doctor If
    • Severe bite pain persists > 2 hours after pain medicine
    • Abdominal pains or muscle spasms occur
    • Local pain lasts > 2 days (48 hours)
    • Bite begins to look infected
    • Your child becomes worse or develops any of the “Call Your Doctor” symptoms