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Poisoning Due to Black Widow Spider Venom (Black Widow Spider Bites)
Learn how people often react to black widow spider bites. Read about how they can be treated and avoided.

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Black Widow Spiders

Black widow spiders are easily recognizable. They are plump, black, and shiny, with an hourglass-shaped red mark on their abdomens. Sometimes, this red mark may take a slightly different shape. In other cases, the spider may have red markings on its back too.

This type of spider gets its name from its mating behavior. After mating, the females typically kill and then eat their male partners, leaving them as “widows.”

These spiders are not aggressive and only bite when they feel threatened. The bites are usually not fatal, but can still cause some serious and uncomfortable symptoms.

If a black widow spider has bitten you, get medical treatment right away.

This spider type is found throughout the world. While they are found all over the United States, they are most common the southern and western states.

What Causes a Black Widow Spider to Bite?

Black widow spiders are reclusive and not aggressive. They will never seek you out to bite you. Instead, they only bite in self-defense or when they feel threatened.

Black widow spiders live in dark, hidden spots in piles of rocks, leaves, or wood. Do not move or disturb these piles without wearing gloves, as you might accidentally touch a black widow spider and get bitten.

You should also wear gloves when you are moving things out of dark corners in garages or basements. Black widow spiders may live in these areas.

These spiders might also hide in a variety of other dark places, such as inside your shoes (especially if stored somewhere dark), in piles of unused blankets, in the crevices of porch furniture, and between stones in a rock wall.

What Are the Symptoms of Black Widow Spider Venom Poisoning?

You will usually feel the sensation of a minor pinprick when a black widow spider first bites you. You might not even realize at first that you have been bitten, unless you caught the spider in the act. In some cases, the bite might be painful right away.

The area around the bite may redden and begin to swell.

Within a few hours of the bite—and sometimes in as little as 15 minutes—you will develop more serious symptoms. Most commonly, you will experience pain that is not limited to the bite location. Your chest and abdomen, in particular, will be painful. The muscles in these areas will cramp and go rigid. Your back and shoulders may also hurt.

Other symptoms you might experience include:

  • difficulty breathing (due to paralysis of the diaphragm)
  • nausea
  • chills
  • headache
  • sweating
  • weakness
  • fever

In rare and extreme cases, black widow spider venom poisoning may lead to seizures and even death. Death generally does not occur in healthy adults. Young people, the elderly, and those with weakened immune symptoms are more susceptible to serious complications and death from a black widow spider bite.

Regardless, anyone who has been bitten, or who suspects they have been bitten by a black widow spider, should seek medical treatment immediately.

How Is Black Widow Spider Venom Poisoning Treated?

Treatment for a black widow bite will vary depending on your health, symptoms, and the severity of the bite.

You may be given medication to help ease your pain. You might also be given medications to help lower the high blood pressure that sometimes accompanies a black widow spider bite.

If the bite is more severe, you may need muscle relaxants and/or antivenin. In some cases, you may even need to be hospitalized.

Home Care for Black Widow Spider Venom Poisoning

You should go to a doctor or emergency room right away if a black widow spider has bitten you.

However, there are some steps you can take immediately preceding your trip to the hospital or on the way to the hospital.

  • Wash the bite thoroughly with soap.
  • Apply a wet or damp ice pack for 10 minutes at a time, with 10 minute breaks in between.
  • Elevate the location of the bite, if possible. For example, if you were bitten on your hand, keep your arm over your head. You should also tie a piece of cloth around your limb above the bite to help slow the spread of the venom. Tie the cloth snugly, but not too tightly.
  • Get to a hospital immediately.
Written by: Gretchen Holm
Edited by:
Medically Reviewed by:
Published: Jul 18, 2012
Published By: Healthline Networks, Inc.
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