Here’s What Spider Bites Look Like—and When to Call the Doctor
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Spiders are probably more scared of you than you are of them. They'd sooner scurry away than chomp on you. But if you get bitten, here's what you should do.
Here’s the good news: Unlike chiggers, which feast on your skin, or mosquitoes, which suck your blood, spiders (arachnid) don’t see you as food. In fact, they would rather keep their distance. “They have no interest in dealing with people. It would be like us going up against Godzilla, says arachnologist Rick Vetter, now retired from the University of California, Riverside, and author of The Brown Recluse Spider. Even if we do encounter spiders, they rarely bite. Here’s what entomologists want you to know about spiders and their bites.
Miguel Ángel Ramírez Velazco / EyeEm/Getty Images
Why do spiders bite?
In a nutshell, it’s self-defense. “In general, spiders will bite only if they can’t get away from you, or are protecting their babies and don’t want to leave the babies behind, and/or they are being crushed or otherwise hurt,” says Sebastian Alejandro Echeverri, PhD, who studies spiders at the University of Pittsburgh. Even the black widow doesn’t bite as often as many people believe. A 2014 study published in Animal Behaviour tested various scenarios to find how often a black widow would bite. Even with continued poking, the black widow spiders either played dead or spit out silk instead of biting. Only one spider out of 43 actually bit the gelatin “fingers,” used for the tests. The biting increased to 60 percent only when the spider was pinched between two gelatin fingers for an extended period. Still, the fear of spiders is debilitating for some people.
Do spiders have dangerous venom?
“Yes, almost all species of spiders have venom, but that venom has evolved to work on animals that the spider eats. And there are no spiders in the world that eat humans,” says Echeverri. Spiders feast on insects such as mosquitoes, flies, moths, beetles, and other spiders. Larger spiders might eat lizards and frogs. “Our bodies are so much larger and built so differently than the insects and other animals that spiders do eat, that the vast majority of spiders’ venom just doesn’t work on us,” says Echeverri.
Black widow and brown recluse are venomous
Each individual has his or her own unique response to spider bites. Symptoms may be minor to severe. According to the Centers for Disease Control and Prevention (CDC), the only two spiders in the United States considered venomous, are the black widow and brown recluse. The venom of the black widow contains a neurotoxin that can cause pain at the bite area that spreads to the chest, abdomen, or entire body. However, death occurs in less than one percent of black widow bites. The brown recluse venom has the potential to destroy skin and cause a severe lesion, for which medical attention may be necessary. Death is rare from a brown recluse bite and reported mainly in children.
Unless you got a good look at what bit you, it’s difficult to know if the bite came from a spider or an insect—you might even suspect an insect that looks like a spider, such as the jumping spider cricket, which isn’t a spider and doesn’t bite. “Not all skin reactions are bites from an arthropod. You can’t 100 percent identify what bit you based on a skin lesion. Nor can you diagnose a skin reaction and attribute it to any animal unless you see it biting you or slapped it dead,” says entomologist Jody Green, PhD, at the University of Nebraska, Lincoln. “There are so many other reasons for skin lesions besides spiders,” adds Green.
Dermatologist Adam Friedman, MD, professor and interim chair of dermatology at The George Washington University School of Medicine and Health Sciences, says that anything short of the skin-cell death a person gets with a bite like the brown recluse’s will look the same. In other words, you might not be able to say what bit you with confidence, and red bump bug bites are rarely serious and can be treated at home.
Still, medical treatment might be necessary if your symptoms are severe or if you suspect a black widow or brown recluse bit you—never ignore those bug bites.
Spider bite symptoms
Remember that from one person to the next, the reaction to a spider bite can be very different. Children, the elderly, pregnant women and those with compromised immune systems might have more severe reactions. The CDC lists possible symptoms of spider bites as:
- Itching or rash
- Pain radiating from the site of the bite
- Muscle pain or cramping
- Reddish to purplish color or blister
- Increased sweating
- Difficulty breathing
- Nausea and vomiting
- Anxiety or restlessness
- High blood pressure
Also, some individuals may experience anaphylactic shock, an allergic reaction to the venom. Symptoms include rash, hives, intense itching, swelling and redness, sudden swelling of the lips, eyes, tongue, or throat, stomach cramps, trouble breathing or wheezing, or loss of consciousness. (A painful rash could also be a symptom of shingles.)
Spider bite treatments
In general, all spider bites are treated the same way Dr. Friedman says. Here are the steps to treating a spider bite at home:
- Clean the bite with mild soap and warm water
- Apply ointment based moisturizer to damp skin and keep covered with a bandaid if possible
- Take acetaminophen or ibuprofen (so long as not contraindicated) if you have pain
- Apply ice briefly or hydrocortisone one percent cream if you have itching
As its name implies, this spider is a shiny black color with a feature unlike any other—a red hourglass marking on the underside of the females’ abdomen. They’re about 1 to 1.5 inches in size. Males have light streaks on their abdomen and are smaller. More importantly, it is the larger female that has the bite that’s so famous. They live primarily in the temperate regions of the South and West and shun humans if possible. They are content to mind their own business, eating mosquitoes, flies, and other pests we don’t like, all while living quietly outside, close to the ground in garages, rock piles, beneath decks and porches. It’s highly unlikely to see one in your house unless it accidentally hitchhiked in on another object.
Black Widow bite symptoms
You might not even notice when a black widow bites you, or it may just feel like a pinprick—that’s why it’s so challenging to know what bit you. “The bite will appear at first to be a small red bump with surrounding redness and swelling, almost like a hive,” says dermatologist Joesph Zahn, MD, assistant professor of dermatology at the George Washington University Medical Faculty Associates. The initial pain of the bite occurs in just a few minutes and usually subsides within two to three days.” The symptoms may be more severe, depending on how an individual reacts to the venom. In extreme cases, he says, “latrotoxins, a type of neurotoxin in the venom, can cause serious pain and can lead to paralysis.” In addition, sometimes fatal heart damage has been reported, he notes. But he stresses that death due to a black widow spider bite is extremely rare.
Treatment and when to see the doctor
A black widow bite can look like countless other insect and spider bites, but if you suspect or know you’ve been bitten by one, it’s best to get checked out, Dr. Zahn says. Children, pregnant women, the elderly and those with compromised immune systems should see their doctor or head to the emergency department. If you have fevers, chills, muscle pain, aches, difficulty breathing, or other symptoms that affect your entire body, call your doctor. Make sure you’re up-to-date on your first aid knowledge.
Dr. Friedman also suggests a tetanus shot if you haven’t had one in the last decade—tetanus spores can collect inside the bite. Your doctor may recommend prescription medications such as benzodiazepines (a sedative) to help relax your muscles (and you). Antivenin, also known as antivenom, is available for severe symptoms, yet Dr. Zahn adds that it might not work for everyone; it triggers an allergic reaction in some people. A doctor can help you determine your risk based on your health history. In Vetter’s experience, antivenin has been quite effective for extreme pain. “Bite victims including small children go from screaming pain back to normal within 30 minutes,” he says.
Also known as the “fiddleback, ” the brown recluse is found in the Southern and Midwestern states and is identifiable by its dark brown violin-shaped body. And as its name implies, it prefers to live undisturbed, away from humans. Outdoors it lives under rocks, woodpiles, and debris. “They might get in the house, usually by being carried around in storage boxes or in luggage being moved around,” says Green. They hang out in places where they won’t be discovered easily, like in rarely used areas of the basement, attic, or crawl space. “Many, many spiders are misidentified as brown recluse spiders every day,” adds Green. Yet, if you ever got close enough, you would notice a difference from most other spiders. “They are one of the few spiders that have six eyes, whereas most spiders have eight,” says Vetter.
Courtesy Adam Friedman, MD
Brown recluse bite symptoms
The good news is most brown recluse bites are mild and self-healing, according to both, Vetter and Dr. Friedman. The bite is usually painless— at first. “A painful, severe swollen reaction occurs within the first eight hours,” says Dr. Friedman. Some people may have mild discomfort while others will develop large blisters. “The blisters are surrounded by reddish and white zones. In about a week, the central portion becomes dark and gangrenous,” says Dr. Friedman. That reaction to the bite is known as loxoscelism. Rarely, some people develop systemic loxoscelism, in which the infection at the site spreads through the bloodstream and can be accompanied by nausea, vomiting, fever, and muscle pain In a severe case, Dr. Friedman says it causes a condition called disseminated intravascular coagulation. “This means your blood both clots too much and can’t clot enough at the same time, which is life-threatening.” (Don’t ignore these bug bite symptoms.)
Treatment and when to see the doctor
People in the following categories should always seek immediate treatment if they suspect or know a brown recluse bit them:
- A child
- A chronic health condition such as diabetes or heart disease
Also, if you feel muscle pain, aches, fevers, chills, difficulty breathing, or other symptoms that affect your whole body, call your doctor. Your doctor might recommend a tetanus shot if you haven’t had a booster in the last 10 years. (While you’re at it, make sure you’re up to date on all your vaccines.)
Wolf spiders are hairy and larger than most common spiders, which might make them seem more creepy and dangerous, but they’re “virtually harmless,” says Vetter. They have a tan to dark brown color and sometimes sport stripes on their body, paler in color. Females are about 1.3 inches long, and males can be up to 2.5 inches long. Wolf spiders aren’t web builders. They live across the United States and favor outdoor ground habitats such as woodland leaf litter, stream edges, and they may burrow under flat rocks or fallen tree logs. Inside, depending on where you live, you might see one in your house in the fall near doors, windows, basements, or garages. They’re just looking for a warm place to hang out as temperatures drop outside.
Wolf bite symptoms
As with any spider bite, the severity of any reaction can differ from individual to individual, but typically, wolf bites aren’t dangerous. “For the most part, it is localized pain, itching, and minor swelling, a red bump,” says Dr. Zahn. “You might notice the symptoms within a few minutes to a few hours after the bite.”
Treatment and when to see the doctor
“For the most part, these bites rarely pose a risk to your health. If you experience fevers, chills, muscle pain, and aches, or other symptoms throughout your body, call your doctor,” Dr. Zahn says. (It’s bug season, make sure you stock up on these chemical-free bug repellents.)
You would think having eight legs would make getting around a breeze, but the hobo spider, also known as the hitchhiking spider, doesn’t climb up vertical surfaces very well, so it likes to travel on people or other objects to get around. That’s why you might see it running across the floor, more than another type of spider. It’s about 3/16 of an inch long and typically a shade of brown with dark stripes or other markings, depending on the species. The hobo lives in the northwestern United States and favors outdoor living in the standard spider spots: Cracks and holes in woodpiles, under rocks, concrete, and window wells. If they do find themselves inside, they seek out dark and moist areas like a basement or crawl space.
Hobo spider bite symptoms
The bite of a hobo spider is barely noticeable. At most, it may feel like a pinprick. Vetter says the bite is harmless and non-toxic. The CDC removed the hobo spider from its list of venomous spiders in 2017. The bite can result in redness in the area for up to 12 hours. Since the bite is painless, it’s difficult to determine how long it might take to see a reaction, Dr. Friedman adds.
Treatment and when to see the doctor
Follow the spider bite treatment above. It’s unlikely you’ll need to see the doctor, but if you have concerns about the bite area, intense itching, pain, and swelling, call your doctor. (Also, here’s when bug bites need medical attention.)
Simon Murrell/Getty Images
Big, hairy, fast, and yes, even beautiful, at least to those that keep them as pets. They are so docile, says Vetter, “that if you were bitten you deserved it.” And that includes the ones outside of captivity that make their home in Southwestern states. They range in size from about four inches to 11 inches. As ground dwellers, they eat insects such as grasshoppers, beetles, other small spiders, and small lizards. Though they have a mild temperament, they can dislodge prickly hairs via their hind legs that irritate the eyes or skin.
Tarantula bite (and prickly hair) symptoms
Given its easygoing personality, a tarantula isn’t likely to bite, but if it does, it might feel like a bee sting or nothing at all, depending on the individual. “Like all spider bites, the bite itself appears as a red bump with surrounding redness and swelling,” says Dr. Zahn.
Treatment and when to see a doctor
Follow the usual first-aid measures for a spider bite and you’ll be fine. However, tarantulas from other parts of the world in the pet trade can cause more severe bite reactions, Vetter adds. If the tarantula shot out some hairs, that will likely cause intense itching and swelling that can be treated with hydrocortisone. Don’t hesitate to consult an ophthalmologist if you experience any eye symptoms from the hairs Dr. Zahn says. “If the hairs get in your eyes they can cause a reaction that leads to permanent vision loss.”
Kidsada Manchinda/Getty Images
Found throughout the United States, the jumping spider’s vision is comparable to humans, Vetter says. They have eight eyes in three rows. The front row has four eyes with two larger eyes in the middle. People often mistake jumping spiders for black widow spiders because they both have compact black bodies with relatively short legs. Yet jumping spiders can also be brown, tan, or gray with colorful markings in yellow, red, blue, green, and white. As their name suggests, they jump (and climb) and can be found waiting for their prey (insects) high in tree trunks or low in window wells. They’re far more likely to be outside than inside.
Jumping spider bite symptoms
Yep—that’s right: If a jumping spider chomps you, you’ll see a small bump that is reddish with a bit of swelling. There may be some itching also, depending on how your body reacts to the bite.
Treatment and when to see the doctor
Follow the spider bite treatment guidelines and see your doctor if persistent itching, swelling, or pain persists. (Learn how to treat every bug bite.)
Also known as sun spiders or wind scorpions, the camel spider is in the solifugae family, an order of arachnids that are neither spiders nor scorpions. They live in Southwestern states and always on the move, Vetter says. But not toward you as some internet rumors would have you believe: They certainly are not half the size of a human, as fake photos suggested. Most American camel spiders are nocturnal and hide in burrows or under flat stones or boards. They can be tiny at barely an inch in size to about four inches. Their hairy and stout body has eight legs like other spiders, but because two legs are held out in front of the body, it looks like they have ten legs. Maybe that’s why they travel so fast—up to 53 centimeters per second. They don’t run fast for long, and they’re not running at you. They eat insects, small lizards, birds, and rodents.
Camel spider bites
Camel spiders are difficult to collect and study. It’s rare to be bitten by a camel spider. Even if one does get you, it might not hurt. According to Colorado State University Extension, a camel spider bite feels like a mild pinch and doesn’t break the skin. They don’t have venomous glands. You might experience slight irritation; a reddish bump might occur on the skin.
Treatment and when to see a doctor
Treat the camel spider bite as you would other spider bites and see a doctor if symptoms don’t get better.
Spider bite prevention
Spiders prefer quiet and out-of-the-way places—a corner in the basement, under storage containers in the garage, or attic. Outside, they favor life under rocks, window wells, nooks, and crannies of the shed, woodpiles, or under the porch. When they sense your presence, they scurry away. Still, avoid an unwelcome encounter and protect yourself by thinking about the areas where spiders might be living that has been relatively undisturbed by human activity, and act accordingly. Wear gloves, long sleeves, and tuck your pants into your socks if you’re working outside. Shake out the boots that have been sitting on the patio. Wash the garden gloves before you put them on. “Watch out for seasonal stuff in the garage like baseball gloves and gardening clothes that sit idle for months. Store them in large zip-closure plastic bags,” Vetter says. (Next, read about the “harmless” bugs that can actually bite.)
Helpful products to ward off spiders
Remember that spiders are our friends primarily because they are effective at netting flies, mosquitoes, and other annoying bugs. but if you’re worried about getting bitten—or need to treat an itchy bite—you’ll appreciate these guides:
Find out more about the fascinating life of spiders, their bashful personality, their webs, and how beneficial they are to humans.
The Brown Recluse Spider, book by Richard S. Vetter
Spiderdaynightlive.com, a website by Sebastian A. Echeverri, PhD
Spiderbytes, a blog by Catherine Scott PhD, department of biological sciences, University of Toronto Scarborough
- Rick Vetter, retired arachnologist Rick Vetter, The University of California, Riverside
- Jody Green, PhD, an entomologist at the University of Nebraska, Lincoln
- Sebastian Alejandro Echeverri, PhD, University of Pittsburgh
- Journal of Arachnology: "Spiders of the genus Loxosceles (Araneae, Sicariidae): A review of biological, medical and psychological aspects regarding envenomations"
- Adam Friedman, MD, FAAD, professor and interim chair of dermatology at The George Washington University School of Medicine & Health Sciences, Washington, D.C.
- Joseph Zahn, MD, assistant professor of dermatology at the George Washington University Medical Faculty Associates, Washington, D.C.
- National Institute for Occupational Safety and Health: "Venomous Spiders"
- PLoS ONE: "Defining the complex phenotype of severe systemic loxoscelism using a large electronic health record cohort"
- Animal Behaviour: "Poke but don't pinch: risk assessment and venom metering in the western black widow spider, Latrodectus hesperus"
- The University of Nebraska Lincoln: "Urban Pest Profile", Wolf Spiders, Amanda Newton, entomologist
- National Center for Biotechnology Information: "Black Widow Spider Toxicity"
- American College of Medical Toxicology: "Spiders (Black Widow and Brown Recluse)"
- University of Nebraska, Lincoln: "Urban Pest Profile, Funnel Spider Amanda Newton"
- Utah State University Extension: "Utah Pests Fact Sheet, Hobo Spider"
- University of Florida: "Featured Creatures, Entomology and nematology"
- Denver Museum of Nature and Science: "The Arachnid Order Solifugae"
- Colorado State University Extension: "Windscorpions (Sunspiders) of Colorado"
- American Museum of Natural History: "Study Takes Close Look at Formidable Camel Spider Jaws"
- Army Public Health Center: "Solifugids, Camel Spiders Fact Sheet"
- Live Science: "Tarantula Facts"
- Live Science: "Camel Spiders: Facts & Myths"