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Spider Bites

Which spider bites are dangerous?

Most spiders found in the United States are harmless, with the exception of the black widow and the brown recluse spiders. Both of these spiders are found in warm climates.

What is a brown recluse spider?

Brown Recluse spider and bite

The brown recluse spider, or violin spider, is about 1 inch long and has a violin-shaped mark on its upper back. It is often found in warm, dry climates and prefers to stay in undisturbed areas such as basements, closets, and attics. It is not an aggressive spider, but will attack if trapped or held against the skin. No deaths have been reported in the U.S. from a brown recluse bite.

What are the symptoms of a brown recluse spider bite?

Venom from the brown recluse spider usually causes local tissue damage. The following are the most common symptoms of a bite from a brown recluse spider:

  • Burning, pain, itching, or redness at the site which is usually delayed and may develop within several hours or days of the bite

  • A deep blue or purple area around the bite, surrounded by a whitish ring and large red outer ring similar to a "bulls eye"

  • An ulcer or blister that turns black

  • Headache, body aches

  • Rash

  • Fever

  • Nausea or vomiting

The symptoms of a brown recluse spider bite may look like other conditions or medical problems. Always see your health care provider for a diagnosis.

What is the treatment for a brown recluse spider bite?

Specific treatment for a brown recluse spider bite will be determined by your health care provider. Treatment may include the following:

  • Wash the area well with soap and water.

  • Apply a cold or ice pack wrapped in a cloth, or a cold, wet washcloth to the site.

  • Protect against infection, particularly in children, by applying an antibiotic lotion or cream.

  • Give acetaminophen for pain.

  • Elevate the site if the bite occurred on an arm or leg (to help prevent swelling).

  • Seek immediate emergency care for further treatment. Depending on the severity of the bite, surgical treatment of the ulcerated area may be required. Hospitalization may be needed.

Prompt treatment is essential to avoid more serious complications, especially in children. 

What is a black widow spider?

Black Widow spider and bite

A black widow spider is a small, shiny, black, button-shaped spider with a red hourglass mark on its abdomen, and prefers warm climates. Black widow spider bites release a toxin that can cause damage to the nervous system, thus emergency medical treatment is needed.

What are the symptoms of a black widow spider bite?

The following are the most common symptoms of a black widow spider bite:

  • Immediate pain, burning, swelling, and redness at the site (double fang marks may be seen)

  • Cramping pain and muscle rigidity in the stomach, chest, shoulders, and back

  • Headache

  • Dizziness

  • Rash and itching

  • Restlessness and anxiety

  • Sweating

  • Eyelid swelling

  • Nausea or vomiting

  • Salivation, tearing of the eyes

  • Weakness, tremors, or paralysis, especially in the legs

These symptoms of a black widow spider bite may look like other conditions or medical problems. Always see your health care provider for a diagnosis.

What is the treatment for a black widow spider bite?

Your health care provider will determine specific treatment for a black widow spider bite. Treatment may include the following:

  • Wash the area well with soap and water.

  • Apply a cold or ice pack wrapped in a cloth, or a cold, wet washcloth to the site.

  • Protect against infection, particularly in children, by applying an antibiotic lotion or cream.

  • Give acetaminophen for pain.

  • Elevate the site if the bite occurred on an arm or leg (to help prevent swelling). 

  • Seek emergency care right away for further treatment. Depending on the severity of the bite, treatment may include muscle relaxants, pain relievers and other medications, and supportive care. Antivenin may be needed, although it is usually not required. Hospitalization may be needed.

Prompt treatment is essential to avoid more serious complications, especially in children.

Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Online Medical Reviewer: Trevino, Healther, M., BSN, RNC
Date Last Reviewed: 11/30/2014
© 2000-2014 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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