Spider Bites
(Including Black Widow and Brown Recluse)
Medical Author: Melissa Conrad Stoppler, MD
Medical Editor: William C. Shiel, Jr, MD, FACP, FACR
Are spider bites dangerous?
Most spiders do not have mouth parts strong enough to penetrate human skin, and the majority of spiders found in the U.S. and are actually harmless. There are two notable exceptions, the black widow spider and the brown recluse spider, which are both dangerous to humans. Spider bites are fortunately uncommon. In many cases, presumed spider bites are actually due to another skin condition or an insect sting.
The black widow and brown recluse spiders are more common in the southern states of the U.S. They prefer warm, dry climates and undisturbed areas such as basements, closets, woodpiles, attics, or under sinks. The black widow spider is a small, black, shiny spider with a red hourglass marking on its belly. The brown recluse spider is sometimes termed a "violin spider." It is about an inch long and has a marking resembling a violin on the upper part of its back. Bites from both the black widow and brown recluse spiders are dangerous to humans and require prompt emergency medical care.
What are the symptoms of spider bites?
Bites from most (non-poisonous) spiders cause local redness, irritation, and pain that usually can be treated at home using an over-the-counter pain reliever along with application of cooling packs or a wet cloth to relieve swelling. These local reactions usually resolve without treatment over a period of 7-10 days. Rarely, an individual can have an
allergic reaction to a spider bite, even to a bite from a non-poisonous spider, but allergic reactions are more likely to be due to contact with a spider than from a spider bite.
Black widow spider bite symptoms
A black widow spider bite is said to feel like a pinprick, although victims may not realize that they have been bitten. Sometimes double fang marks may be seen at the location of the bite. The most common localized symptoms of a black widow spider bite are immediate pain, burning, swelling, and redness.
Picture of the underside of a black widow spider and an egg sack
Picture of a top view of a black widow spider
Next: Brown recluse spider bite symptoms (picture of brown
recluse spider) »
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