Swedish Kids Symptom Checker

Swedish Kids Symptom Checker

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Spider Bite

1. Does this describe your child's symptoms?

This is a photo of the Black Widow spider (Lactrodectus)

  • The black widow is shiny and black, with long legs (total width 1 inch).
  • A red (or orange) hourglass-shaped marking may be on its underside. However, this marking is not present in all Lactrodectus species.

From the CDC's Public Health Image Library (http://phil.cdc.gov), ID#5449, in the public domain.

This is a photo of the Brown Recluse Spider (Loxosceles reclusa).

  • It is a brown spider with long legs (total width 1/2 inch).
  • There is a characteristic violin-shaped marking is visible on back.

From the CDC's Public Health Image Library (http://phil.cdc.gov), ID#1125, in the public domain.


  • Bite from a spider


  • Bite symptoms include redness, pain, swelling
  • Helpful if spider seen on the skin or in close proximity to the child

Types of Spider Bites

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 (especially abdominal wall 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.
  • The brown widow spider is related to the black widow and is found in southern US.
  • Brown widow spider bites are treated the same as a black widow bite.

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, muscle pain can occur (but no life-threatening symptoms).
  • Since brown recluse spiders are hard to identify, bring the spider along in a jar.

Non-dangerous 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).
  • Many single, unexplained, tender bites that occur during the night are due to spiders.

2. When to Call Your Doctor

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

  • Difficulty breathing or wheezing
  • Passed out or too weak to stand

Call Your Doctor Now (night or day) If

  • Your child looks or acts very sick
  • Widow spider (black, brown, red, etc) bite suspected (see FIRST AID)
  • Abdominal pain, chest tightness or other muscle cramps
  • Bite pain is severe
  • Fever and bite looks infected (spreading redness)
  • You think your child needs to be seen urgently

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

  • You think your child needs to be seen, but not urgently
  • New redness starts more than 24 hours after the bite (Note: infection doesn't start until at least 24 hours after the bite. Any redness in the first 24 hours is due to venom)
  • Over 48 hours since the bite and redness now becoming larger
  • Bite starts to look bad (e.g., skin damage, blister or purplish - not just swelling)
  • Bite pain persists over 2 days

Call Your Doctor During Weekday Office Hours If

  • You have other questions or concerns

Parent Care at Home If

  • Non-serious spider bite and you don't think your child needs to be seen


  • Cleansing: Wash the bite thoroughly with soap and water.
  • 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). Do this once. If not available, apply an ice cube in a wet washcloth for 20 minutes.
  • Pain Medicine: Give acetaminophen (e.g., Tylenol) or ibuprofen as needed for pain.
  • Expected Course: Some swelling and pain for 1 to 2 days. It shouldn't be any worse than a bee sting.
  • Call Your Doctor If:
    • Severe bite pain persists over 2 hours after pain medicine
    • Abdominal pains or muscle spasms occur
    • Local pain lasts over 2 days (48 hours)
    • Bite begins to look infected
    • Your child becomes worse
  • And remember, contact your doctor if your child develops any of the 'Call Your Doctor' symptoms.


  • This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.
  • Author and Senior Reviewer: Barton D. Schmitt, M.D.
  • Last Reviewed: 9/15/2011 12:00:00 AM
  • Last Revised: 8/12/2011 6:01:57 PM
  • Content Set: Pediatric HouseCalls Symptom Checker
  • Copyright 1994-2012 Barton D. Schmitt, M.D.
If this is an emergency call 911 immediately.

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Swedish Kids Symptom Checker is designed especially for these times. The interactive iPhone application can help you make appropriate decisions on what level of care, if any, is needed and how to provide symptom relief for minor illnesses and injuries you can manage on your own.

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