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Brown Recluse Spider Bite

Brown Recluse Spider Bite Overview

Most spiders are absolutely harmless to humans. In fact, of the over 20,000 different species of spiders that inhabit the Americas, only 60 are capable of biting humans. Within that small group, only four are known to be dangerous to humans: the brown recluse, the black widow, the hobo or aggressive house spider, and the yellow sac spider. Within this select group, only the brown recluse and the black widow spider have ever been associated with significant disease and very rare reports of death.

  • Deaths from brown recluse spiders have been reported only in children younger than seven years. Brown recluse spiders are native to the Midwestern and Southeastern states. Documented populations of brown recluse spiders outside these areas are extremely rare. In recent years controversy has arisen over the appearance of brown recluse spiders in California and Florida. At this time most experts agree that the brown recluse is not endemic to these areas. With increasing travel, individual spiders and spider bites can be found in areas where the spider is not endemic, and health care practitioners should consider this when treating suspected bites.
  • Fewer than 10 individual spiders have ever been collected outside of these native states. Most false sightings are due to confusion with one of the 13 other species found in the same family.
  • The most common non-brown recluse spiders are the desert recluse found in Texas, Arizona, and California, and the Arizona recluse. No deaths have ever been reported from non-brown recluse spiders. Bites from these cousins produce mild to moderate local skin disease.

Features: Brown recluse spiders are notable for their characteristic violin pattern on the back of the cephalothorax, the body part to which the legs attach. The violin pattern is seen with the base of the violin at the head of the spider and the neck of the violin pointing to the rear. These small non-hairy spiders are yellowish-tan to dark brown in color with darker legs. They have legs about one inch in length. The name of the genus, Loxosceles, means six eyes. Most other spiders have eight eyes. Yet this unique feature of the brown recluse is lost on the casual observer because the eyes are too small to be seen with the naked eye.

Habits: These spiders are not aggressive and bite only when threatened, usually when pressed up against the victim's skin. They seek out dark, warm, dry environments such as attics, closets, porches, barns, basements, woodpiles, and old tires. Its small, haphazard web, found mostly in corners and crevices, is not used to capture prey. Most bites occur in the summer months.

Picture of Brown Recluse Spider
Picture of Brown Recluse Spider

Medically Reviewed by a Doctor on 5/23/2014

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Read What Your Physician is Reading on Medscape

Spider Envenomations: Brown Recluse »

In the United States, reports of severe envenomations by brown spiders began to appear in the late 1800s, and today, in endemic areas, brown spiders continue to be of significant clinical concern.

Read More on Medscape Reference »


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