Black widow spiders (Latrodectus mactans) are found throughout the Western Hemisphere. A female black widow is much more likely to deliver more venom than a male spider.
Female black widows are long-legged, shiny, coal-black spiders with an orange, red, or yellow hourglass shape on the underside. The female black widow is usually about 1.5 in. (3.8 cm) long, but may be smaller.
Black widow spiders tend to bite defensively when their webs are disturbed. Black widow spiders are frequently found in low-lying webs in garages, barbecue grills, around swimming pools, and in wood piles. Bites to babies and children may be more serious than bites to adults. Signs and symptoms of a black widow bite include:
In some cases, severe symptoms appear within 30 to 60 minutes. These include:
A doctor should be contacted immediately when a person is bitten by a black widow spider.
Last Revised: October 14, 2011
Author: Healthwise Staff
Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine
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