What is brown recluse spider bite?

Brown Recluse Spider Bite

Brown recluse spider bite: Overview

After being bitten by a brown recluse spider, you may have red skin and a blister where you were bitten. You may also have intense pain and itching around the bite. This may last a few hours.

In some cases, an open sore or black skin can appear around the bite. This can happen a week or more after you were bitten. This is a serious problem that needs medical attention.

Brown recluses are found most often in the south-central part of the United States. They live in hot, dry, abandoned areas, such as wood or rock piles. They can also be found indoors in dark closets, shoes, or attics.

What are the symptoms of a brown recluse spider bite?

Brown recluse spider bites don't always hurt right away. In fact, you may not know that you have been bitten until other symptoms appear. Symptoms of a brown recluse spider bite include:

  • Reddened skin that may be followed by a blister that forms at the bite site.
  • Mild to intense pain and itching for 2 to 8 hours following the bite.
  • An open sore (ulcer) with a breakdown of tissue (necrosis) that develops a week or more following the bite. This may take months to heal.

Some people have a severe, systemic (whole-body) reaction to brown recluse spider bites, including the rapid destruction of red blood cells and anemia (hemolytic anemia). Signs and symptoms include:

  • Fever and chills.
  • Skin rash all over the body with many tiny, flat purple and red spots.
  • Nausea or vomiting.
  • Joint pain.

How is a brown recluse spider bite treated?

Treatment depends on how severe the bite is. For bites that:

  • Do not develop open sores, treatment includes applying a cold compress, elevating the bite area, and avoiding moving the bite area.
  • Cause an open sore (ulcer) and dead skin (necrosis), treatment includes removing the dead skin from the sore. This may involve follow-up and replacing the dead skin with new skin (skin grafts).

Hyperbaric oxygen therapy may also be used for tissue damage from a spider bite.

Medicines that may be used include:

  • Pain medicine, such as acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs include naproxen (Aleve) and ibuprofen (Advil, Motrin). Be safe with medicines. Read and follow all instructions on the label.
    Do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.
  • Antihistamines to help relieve itching.
  • Antibiotics, if an infection is present.

Medicine to counteract brown recluse spider venom is not available in the United States or Canada.

How is a brown recluse spider bite diagnosed?

A brown recluse spider bite is diagnosed through a physical examination and questions about the bite. You should be prepared to describe the spider, where and when the bite took place, and what you were doing at the time. (If you are able to safely capture and transport the spider, bring it with you to show your doctor.) Your doctor will ask what your main symptoms are, when they began, and how they have developed, progressed, or changed since the bite.

Caring for yourself after a brown recluse spider bite

  • Remain calm.

    Try to stay relaxed.

  • Cool the bitten area.

    Apply a cool, wet cloth to the bite, or cover the bite with a cloth and apply an ice bag.

  • Do not apply a tourniquet.

    A tourniquet may cause more harm than benefit.

  • Identify the spider.

    Try to positively identify the spider, or try to take a picture of it.

A brown recluse bite can be serious and may require immediate medical care if you have severe symptoms throughout your body. Call your doctor if an open sore and necrosis develop. Necrosis is black, dead tissue.

Brown Recluse Spider

Brown recluse spider

Source: Public Health Image Library (PHIL). Available online: http://phil.cdc.gov

Brown recluse spiders (Loxosceles reclusa), also called violin spiders or fiddleback spiders, are found most often in the south-central part of the United States and live in hot, dry, abandoned areas, such as wood or rock piles. They are about 0.5 in. (1.3 cm) long with a dark violin-shaped mark on the combined head and midsection (cephalothorax). They have 6 eyes grouped in 3 pairs rather than 8 eyes like other spiders.

Brown recluse spider bite: When to call

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness).
  • You have severe trouble breathing.

Call your doctor now or seek immediate medical care if:

  • You get an open sore or black skin at the bite area.
  • You are dizzy or lightheaded, or you feel like you may faint.
  • You have new symptoms such as fever, vomiting, or a headache.
  • You have symptoms of infection, such as:
    • Increased pain, swelling, warmth, or redness.
    • Red streaks leading from the area.
    • Pus draining from the area.
    • A fever.

Watch closely for changes in your health, and be sure to contact your doctor if:

  • You have new or worse pain at the bite area.
  • You do not get better as expected.

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The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.

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