Everything You Never Wanted to Know About Spiders, In Case One Bites You

Of all the things to be afraid of, spiders and spider bites don’t need be at the top of your list for health reasons: Only two spiders in the U.S. are venomous, and they don’t bite often and hardly ever kill or even injure humans. (Phew!)

The others may be ugly and they may bite–but they’re not harmful.

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“People get over-alarmed when they have a spider bite,” says registered pharmacist Julie A. Weber, director of the Missouri Poison Center in St. Louis. “And sometimes, it might not even be a spider bite.” In fact, up to 90% of the bumps people attribute to spiders are actually caused by something else.

That said, if you do get bitten by a spider, try to catch it (without getting bitten again) so it can be identified by an expert. That will help identify the best way to treat your bite. Read on to learn more about types of spiders that bite and their symptoms and treatments.

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The majority of spider bites are from nonvenomous spiders. The best first aid is to clean the area with soap and water and apply an antibiotic ointment. Mark the date on your calendar, says Weber, who is also director of the poison center at SSM Health Cardinal Glennon Children’s Hospital, and keep your eye on how the bite progresses for any signs of infection.

Non-venomous spider bites don’t typically require medical treatment, but if you’re worried, you can always call your local poison control center “to put your mind at ease,” Weber adds. (You can contact the national Poison Help Hotline at 1-800-222-1222 or text POISON to 797979 to save the number in your phone.)

Then, remember the acronym RICE, advises Rick Vetter, a world-renowned expert on spider envenomation and a retired research associate at the University of California Riverside. It stands for: rest, ice (to reduce pain and swelling, usually with cold compresses), compression, and elevation (of your arm or leg, if that’s where you were bitten). 

Over-the-counter pain relievers may help with any pain from your spider bite, and antihistamines can ease swelling or itchiness.

Call your doctor or go to an emergency room if the bite area looks infected (say, it’s warm to the touch or exuding pus) or if you have more severe symptoms. The good news is that you have a window of several hours to get medical help, even if you’ve been bitten by a black widow or brown recluse spider.

“You always have time,” says Weber. “Symptoms can begin anywhere from one to three hours and can intensify over several hours to a whole day.”

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Most everyday spiders are not venomous, and that includes the jumping spider. It’s one of the most common household spiders and is found all over North America.

Jumping spiders bite, but they usually cause itching and little else. 

“Jumping spiders have good vision and some have an attitude, and if they see a finger they may bite, but I can’t say it has any effect,” says Vetter. “Jumping spider bites resolve in a couple of hours.”

Very similar to the jumping spider, wolf spiders are common and found all over the United States. They’re also not harmful, though you may have a red bump along with a little pain and itching.

“If they bite, it will hurt because of the fang penetration, but in North America, there’s no known wolf spider that can cause you to go to the doctor,” says Vetter.

Benadryl or oral antihistamines can help with the itching, adds Weber.

The brown recluse is one of two dangerous spiders in the United States. Recluse spiders are found in some parts of the Midwest but more in southern states: Missouri, Tennessee, Kansas, Arkansas, Louisiana, Oklahoma, Texas, Mississippi, Alabama, and Georgia.

“Ninety percent of recluse bites, at least in North America, just involve inflammation and nothing more,” says Vetter. “Ten percent can take a long time to heal.”

A classic sign of a brown recluse bite is a sunken area where the bite took place.

“If you truly have a brown recluse bite, it’s going to be a small vesicle [blister], and it’s going to sink down,” says Weber. “It doesn’t get puffed up like a normal bump. It sinks down in the middle.”

That’s because the venom destroys the network of capillaries around the bite, causing the skin to start dying. 

Brown recluse bites may also leave a bull’s-eye mark with a blue center surrounded by a ring of white and a ring of red. Some people have nausea and vomiting, a rash over their body, fever, chills, and joint stiffness anywhere from 24 to 72 hours after the bite occurs.

Apply ice to the bite and make your way to a doctor or ER, where you may be given antibiotics. If your urine turns orange or cola colored, it’s cause for immediate concern, Weber says. “The venom is breaking down red blood cells.”

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Known for their black bodies with red hourglass markings, black widow spiders are the second of the two dangerous spiders in the U.S. They’re more common in southern and western states, says Vetter.

Their bites can be harmful, but “most of the time people say it feels like a bad case of the flu and they ride it out,” he says.

In other cases, pain from a black widow spider bite can become so intense, people have mistaken it for appendicitis or a heart attack. “They get super-severe muscle cramping and pain that radiates from the bite site and up the limb,” says Weber. “[Other] symptoms we look for are sweating. It could either be the whole body or part of a limb, like the shin.”

Once again, apply ice or a cool compress and seek medical attention. Your doctor may recommend an antivenom for a black widow bite if your symptoms are severe.

Hobo spiders, which are concentrated in the Pacific Northwest, get a bad rap for being “aggressive house spiders,” but you have to really push one to get it to bite you.

“They have an unearned reputation as being dangerous,” says Jerome S. Rovner, PhD, professor emeritus of biological sciences at Ohio University.

More than half of hobo spider bites are “dry,” meaning they don’t inject any venom (which is better reserved to kill food). Bites that actually involve venom may produce some itching and small lesions, says Weber.

Despite its name, a camel spider is actually not a spider at all. It has no venom glands, and it can’t spin webs. The critters earned the misnomer from U.S. soldiers in the Middle East. They are arachnids (as are spiders, mites, and ticks) and known as windscorpions in the U.S., explains Rovner.

“They are non-venomous but can defensively inflict an incision-like wound with their jaws if trapped against your skin,” he says. “The species in the U.S., all of which occur in the western part of the country, are small and harmless.”