Spiders That Bite

There are more than 50,000 types of spiders in the world. All spiders have eight legs, no wings, and only two body parts: a thorax and an abdomen. They also all have fangs and enough venom to kill the insects that make up their diet. But only a handful of spiders have fangs and venom that can penetrate human skin — including the brown recluse spider, hobo spider, camel spider, wolf spider, black widow spider, and banana spider. Most spiders are harmless and will bite only if they feel threatened. But depending on the spider and its victim, spider bites can cause anything from mild itching and redness to a reaction that becomes a medical emergency. Here’s detailed info on some common spiders and their bites.

The brown recluse spider gets its name from its habit of living in dark corners inside or outside homes, such as in woodpiles, closets, attics, and basements. This spider is more common in areas that have warm and dry climates, like the south and central areas of the United States. The brown recluse is about a half-inch to an inch long, is light brown in color, and has a violin-shaped mark on its back. The distinctive mark gives the spider these other nicknames: the violin spider or fiddleback spider.

The brown recluse spider’s venom may cause burning pain and itching within several hours after a bite. The actual bite may cause a stinging sensation or not be felt at all. The bite has the appearance of a bull’s-eye, with a central blister that scabs and falls off, leaving a small ulcer. Possible symptoms include body aches and fever. Children may be at risk for an allergic reaction to the venom. To treat a brown recluse spider bite, immediately wash it and apply an ice pack. You can also use an antibiotic ointment to prevent infection. In most cases, symptoms resolve within 48 hours, but the central ulcer may take weeks to heal.

The black widow spider is about the same size as the brown recluse spider (a half-inch to an inch long) and also likes dark places. This spider is usually found outside in sheds, barns, or woodpiles. The black widow can be identified by her shiny black color and a red or orange hourglass marking on the underside of her abdomen. Only the bite of the female spider is dangerous. Black widows can be found throughout the United States but are most common in warmer and drier areas.

The victim of a black widow spider's bite usually feels it right away, and there may be fang marks and swelling. If you are bitten, you should clean and ice the bite. If the spider has injected venom, you may experience muscle aches and cramps that spread from the bite area to the rest of the body. Possible symptoms include nausea, difficulty breathing, and weakness. If someone bitten by a black widow spider experiences muscle cramps, emergency medical care may include blood pressure medication, muscle relaxants, and, in rare cases, antivenin — a biologic product created to counteract the effects of a spider’s venom. Serious reactions are rare, but are most common in children or very elderly people.

The hobo spider is not native to the United States. It arrived in the northwest from Europe and is now common in California, Oregon, Utah, and Washington. The spider is about one-half inch long and has long legs that allow it to move quickly on the ground. Its upper body is brown and its abdomen is grayish with yellow markings. The hobo likes to live in cracks or holes both inside and outside.

The hobo bite resembles the brown recluse bite, with a central blister that scabs and ulcerates, surrounded by a ring of swollen discoloration. Within an hour after the bite, the hobo spider’s venom can cause a numbing sensation and muscle or joint aches. After about three days, a black scab falls off, leaving an open, slow-healing type of wound.

The wolf spider is common all over the United States. It doesn’t weave webs, and it gets its name from its habit of stalking prey like a wolf. The wolf spider is brown or gray in color and can be 3 to 4 inches across. Because some wolf spiders are large and hairy, they are sometimes mistaken for tarantulas. The female may be identified by a white egg sac that she carries with her. This spider prefers to live outdoors on the ground in loose sand or gravel, but it may wander indoors and be spotted running across the floor.

The wolf spider’s bite can cause pain, redness, and swelling. Its large fangs may tear the skin, which can become infected and cause lymph nodes to swell. Treatment of a wolf spider bite includes cleansing and icing. Swelling and pain can last up to 10 days, but medical attention is usually not necessary unless the victim is a small child or someone who is sick or elderly.

Camel spiders are sometimes called wind scorpions or sun spiders, but in reality, they are neither scorpions nor spiders. They belong to a group of desert creatures called solpugids, and they have elongated bodies that make them look more like scorpions than spiders. The name, derived from Latin, means "escape from the sun." In the United States, camel spiders can be found in the deserts of the southwest. They are light brown in color, can be up to 5 inches long, and can run at about 10 miles per hour — often making a screaming sound while doing so.

During the Iraq war, soldiers described huge camel spiders that seemed to run at them in a screaming attack mode. In reality these creatures, though scary in appearance, are not dangerous to humans, and if they run at someone, they are probably just seeking shade in the person's shadow. They do not have any venom and do not bite except in self-defense. A bite is very unlikely and would not be dangerous to a person if it did happen.

The banana spider is found in warm regions of the United States from North Carolina through the Gulf states. It lives in woodlands and forests and produces large, intricate orb webs that glow golden in the sun. The female has a long shape that resembles a banana. She can be about three inches long and has yellow spots on her tan cylindrical body and brown and orange tufts on her legs. The male banana spider is an inconspicuous dark brown and less than an inch long.

The banana spider is often confused with the Brazilian wandering spider, which is found among bananas shipped to the United States from South America; neither spider is native to North America. Although the Brazilian spider bite can be dangerous, the banana spider bite is not. Banana spiders will bite only if held or pinched. The bite produces mild stinging and redness (similar to a bee sting) that quickly goes away.