What Happens When You Get Bit By A Spider?
How to Know When a Spider Bites and What to Do About It
- 1 How to Know When a Spider Bites and What to Do About It
- 2 Identifying a Spider Bite: What Does One Look Like?
- 3 Spider Bites Usually Heal on Their Own. Here’s When to Seek Medical Attention
- 4 Why Do Spiders Bite People?
- 5 Spider Bites: What You Should Know
- 6 Symptoms of Spider Bites
- 7 Diagnosis
- 8 Treatment
- 9 Prevention
- 10 Do You Have A Spider Bite? These 7 Photos Can Help You Tell
Medically Reviewed by Ross Radusky, MD
You spot an angry-looking red welt on your leg, and it seems too big to be a mosquito bite. Must be a spider bite, right?
Not so fast. “People wake up in the morning and find a red mark, and immediately call it a spider bite,” says Rick Vetter , a retired staff research associate and entomologist at the University of California, Riverside. But, he says, most of the skin issues people pin on spiders are actually other types of bug bites or skin issues.
Other researchers back Vetter up on this. “Spider bites are really rare,” says Jonathan Day, PhD , a professor of medical entomology at the University of Florida. He explains that most “spider bites” are more likely mosquito bites that were scratched and became infected. “Spider bite is a catchall grouping whenever there’s a severe skin infection; they’re all lumped in as spider bites,” he says.
So the first thing every spider expert in America would like people to know about spider bites is that they’re uncommon and often misdiagnosed. That said, some spiders do bite people, and the result can be ugly.
Identifying a Spider Bite: What Does One Look Like?
A lot of things. “There’s no one true spider bite,” Vetter says.
Spider Bites Can Look Very Different
Different types of spider bites may provoke different reactions in different people, he says. Even if you’re talking about just one type of spider — say, the brown recluse — its bite could cause a range of reactions: “everything from a little pimplelike bump to a rotting-flesh lesion,” he says.
At the same time, Vetter allows that different types of spider bites do produce distinct reactions. “I’ve had patients contact me saying, ‘This mark on my leg was either from a widow or a recluse,’ but that’s like saying you either got stabbed or trampled to death,” he says. His point: Black widow and brown recluse bites are so different that they could never be mistaken for one another.
But when it comes to common household spiders, hobo spiders, and other domestic varieties, a spider’s bite has some predictable characteristics.
How to Identify Which Spider Bit You
Broadly speaking, a spider’s bite tends to resemble a bee sting: a sharp prick of pain is followed by a red, inflamed skin lump that may hurt or itch but that goes away after a few days. (1) But when it comes to venomous spider bites, there are characteristic signs and symptoms.
Brown recluse bites sting, and they can resemble anything from small blisters to large, rotting-flesh sores, Vetter says. “Its bite causes the collapse of the capillary bed”— also known as skin necrosis (2) — «so people who are obese and have poor support of the capillary cells may have a more massive reaction,” he explains. Along with a wide variety of skin symptoms, brown recluse bites can cause chills, fever, nausea, and other flu-like symptoms common to infections. (3) The brown recluse’s bite is poisonous and can result in coma, kidney failure, or even death.
Because of the severe reaction a brown recluse bite can trigger, these spiders are likely blamed for more harm than they actually cause. The reality is that the brown recluse spider is limited in its geographic range: It’s found in the central and southern United States. (4) The Centers for Disease Control and Prevention (CDC) notes that while venomous spiders are dangerous, they aren’t usually aggressive. (2)
Black widow bites can in some cases cause skin lesions, ranging from small red marks to angry, red, streaky skin patches that are inflamed or contain pus. “But most of the reaction will be on the inside,” Vetter says.
Black widow bites contain potentially deadly amounts of venom and tend to be painful right away. Although that pain starts around the bite site, within an hour, it often spreads to the chest or abdomen, depending on whether the bite occurred on the victim’s upper or lower body. Other symptoms can include everything from headaches, muscle weakness, and difficulty breathing, to seizures, numbness, and painful muscle cramps. (5)
Hobo spiders, wolf spiders, house spiders, and the bites of other domestic types do not contain venoms that are of medical importance to humans, Vetter says. They can bite, he adds. But the result is likely to be similar to a bee sting — meaning a sharp pain, followed by a swollen, red, painful lump at the bite site.
Spider Bites Usually Heal on Their Own. Here’s When to Seek Medical Attention
If you think you were bitten by a black widow or brown recluse spider — either because you actually felt and saw the spider, or you’re experiencing the types of skin or systemic symptoms consistent with their bites — head to the emergency room. (6) Vetter says that recluse bites do usually heal on their own and don’t cause scarring wounds. But it’s better to play it safe.
If your spider bite isn’t causing any internal symptoms, or you’re sure it wasn’t a black widow or brown recluse that bit you, follow these steps:
- Clean the bite with soap and water.
- Swab the bite with alcohol to prevent an infection, Dr. Day recommends.
- Apply ice or a cold compress to keep the swelling down.
If pain or itching develops at the bite site, it’s fine to take OTC pain meds or antihistamines for relief. But if pain spreads beyond the site of the bite, or if the swelling, inflammation, or redness are getting worse even a day or two after the bite occurred, get medical attention. You may have a secondary infection — something caused by bacteria getting into the bite — or you may have been bitten by a widow or recluse, Day says.
Why Do Spiders Bite People?
Unlike many other biting bugs, spiders are neither bloodsuckers nor flesh eaters. Vetter says they bite people for one reason only: self-defense.
“Biting is a last-ditch defensive response if a spider is being squashed,” he says. This can happen when someone rolls over in bed on top of a spider — or sits down on one, he says. “I’ve transferred spiders hundreds of times, and they’ll be running all over my arm and have no interest in biting,” he adds.
So while spider bites do occur, they’re far less common than most people assume.
Spider Bites: What You Should Know
In this Article
In this Article
In this Article
- Symptoms of Spider Bites
Unless you see a spider bite you, donвЂ™t assume that mysterious bump on your skin came from an eight-legged creature. Spider bites are fairly rare.
These eight-legged creatures do bite people on occasion. But most of the time, these bites donвЂ™t cause a problem. ThatвЂ™s because most of the spiders in the U.S. have fangs that are too short to break your skin, and their venom isnвЂ™t strong enough to endanger a creature as large as a human.
Only two spiders that are native to the U.S. can do real harm when they bite a person: Black widows and brown recluses. Black widows tend to live in woodpiles, along fences or in outhouses in the South and West. Brown recluses tend to live in garages, attics or piles of rocks or firewood in the Midwest or South.
Both of these spiders tend to keep to themselves. They donвЂ™t bite unless theyвЂ™re cornered. People sometimes invade their spaces without knowing it. ThatвЂ™s when they get bitten.
Symptoms of Spider Bites
Most look like normal bug bites, with red raised bumps that might itch. Bites from black widows or brown recluses may or may not look different. (In fact, bites from brown recluses may look and feel like nothing at all at first.) But if youвЂ™re bitten by either of these spiders, youвЂ™ll have symptoms that let you know right away that somethingвЂ™s wrong. These might include:
- Sharp pain or swelling at the site of the bite
- Pain that spreads to the back, belly or chest
- Severe stomachcramps or painВ (most common with black widow bites)
- Feeling achy all over
- Joint pain
- A deep ulcer that forms at the site of the bite, with the skin at the center turning purpleВ (can occur from brown recluse bites)
Your doctor will ask about your symptoms and how you were bitten. HeвЂ™ll want to know if you saw a spider bite you, and if you did, what the spider looked like. ThatвЂ™s really the only way he can know for sure that it was a spider that bit you.
If you have more than one bite on different parts of your body, or if several people in your house were also bitten, a spider is probably not to blame. In this case, your doctor will examine you to rule out other causes, like infection or vasculitis (a condition that causes blood vessels to swell).
Many people who are bitten by spiders donвЂ™t need to visit the doctor, even if theyвЂ™ve been bitten by a black widow or brown recluse. If you donвЂ™t have more severe symptoms like the ones listed above, you may be able to care for your spider bite at home. Try these tips so ease your pain or discomfort:
- Clean the wound with soap and water.
- Dab it with antibiotic cream.
- Elevate (raise) the area that was bitten to reduce swelling.
- Put an ice pack on the bite.
- Take over-the-counter pain medicine, if needed.
- Watch for more severe symptoms.
See a doctor right away if you were bitten by a black widow and y have extreme pain or other serious symptoms. He may need to give you an antivenom shot.
If the site of bite gets infected, you may need antibiotics. You might also need to get a tetanus booster. ThatвЂ™s because tetanus spores sometimes collect inside spider bites.
You can try to avoid spider bites by doing your best to not cross paths with spiders.
For example, if you spend time working outside in places where spiders may live:
- Wear long-sleeved shirts, hats and gloves.
- Tuck your pants into your socks.
- Shake out garden gloves and other clothing before putting them on.
- Store gardening clothes in a tightly sealed plastic bag.
- Move piles of firewood and stones away from your home, and use caution around them.
To prevent spider bites while indoors, try to avoid storing items in cool, dark spaces, like under the bed. And make sure that all windows and doors have screens. ItвЂ™ll help to keep the bugs out.
Mayo Clinic: вЂњSpider bites — Overview,вЂќ Spider bites — Symptoms and Causes,вЂќ вЂњSpider bites — Treatment,вЂќ вЂњSpider bites — Diagnosis,вЂќ вЂњSpider bites — Prevention.вЂќ
CDC: вЂњTypes of Venomous Spiders,вЂќ вЂњVenomous Spider Recommendations.вЂќ
Nemours Foundation: вЂњBug Bites and Stings.вЂќ
U.S. Department of Labor: вЂњBrown Recluse Spider.вЂќ
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Do You Have A Spider Bite? These 7 Photos Can Help You Tell
And here’s when you should see a doctor.
When it comes to spider bites, there’s literally one person ever for whom it’s been a great experience (what up, Spiderman?). and he’s fictional.
For the rest of us non-superheroes, getting bit by an eight-legged critter is something we’ll do anything to avoid. And with good reason: At best, getting bitten by a spider is an icky, slightly painful experience. But, at worst, it can be a life-threatening nightmare.
The good news: Out of the 3,000 or so types of spiders in the U.S., only a handful are known to bite, and of those, only about three are venomous and poisonous spiders and can put your life at risk, according to research published in American Family Physician. And if you’re wondering how long spider bites take to heal? While certainly itchy and annoying, most bites heal up within a week (other than brown recluse and hobo spider bites, which can unfortunately take weeks or much longer to heal, depending on whether you develop an infection).
But if you don’t happen to be a spider expert, how do you know if your spider bite is cause for serious concern—or how to make the itching and burning stop? The Instagram photos below (all reviewed by experts) will give you an idea of what different types of spider bites look like—and what you should do if you spot one on your bod.
A post shared by Arturo (@warmloaf) on Jan 6, 2018 at 2:15pm PST
Sometimes, spiders leave behind two distinct puncture holes right next to each other—but unless you actually see the spider do the dirty deed, it’s hard to know if it was caused by an arachnid or some other biting bug.
In fact, the vast majority of «spider bites» are actually bites from other insects like fleas, ticks, and mosquitoes; are a rash from an allergic reaction; or are skin abscesses from an infection, says Justin Arnold, D.O., assistant professor of emergency medicine at the University of Alabama at Birmingham, and the associate medical director of the Alabama Regional Poison Control Center at Children’s of Alabama.
The symptoms are often similar, too—pain, swelling, itching, and redness—so it’s an easy mistake to make. In fact, even spider experts and medical professionals have a hard time differentiating bug bites from spider bites just from how they look, he adds.
«Many people don’t recall an injury or specific bite and hold a common belief that a spider must have bitten them without them knowing,» he says. «In a majority of the cases that we see, a spider was never seen by patient and is not responsible for their infection.»
A post shared by @ yuckygross on Dec 19, 2016 at 8:11am PST
While poisonous bites are rare, any bite—spider or otherwise—can turn serious if it becomes infected, says Arnold. There are three main complications that can arise from bites: cellulitis, blisters, and swelling, says Arnold.
When a spider bite turns into cellulitis—a common (although painful) skin infection—a rash begins to spread around the wound, and the skin becomes painful and hot to the touch.
Another common reaction to many spider bites is to get «weeping» blisters at the site (they look puffy and fluid-filled). Small blisters on their own, with no other symptoms, don’t necessarily need special care. But if a blister opens, it becomes at risk for infection, says Arnold, so don’t try to pop them! If you think you may have an infection at the bite site, whether from cellulitis or open blisters, it’s best to have your doctor take a look.
Swelling is another very common symptom of insect or spider bites. Even though the swelling can get quite pronounced it’s not necessarily a problem, as long as it goes down within a few days. But if the swelling doesn’t go down, gets significantly worse, or is accompanied by other symptoms, it’s time to get medical attention, says Arnold.
A post shared by Helen Harding (@hchharding) on Jan 27, 2018 at 4:21pm PST
The two most common spider bites are from house spiders, specifically the jumping spider and the wolf spider. While it can be scary to be bitten by any spider, these bites normally aren’t any more painful than a bee sting and shouldn’t cause problems beyond some redness, swelling, and itching, Arnold says.
Treat these at home by washing the site with soap and water, using cold compresses, and taking an ibuprofen to reduce pain and swelling, he adds.
A post shared by Caitlin Miller Calder (@y2caitlin) on Apr 3, 2014 at 8:16am PDT
Of all of the spiders, black widows pose the greatest health threat to Americans, according to Rick Vetter, Ph.D., a spider expert in the department of entomology at the University of California, Riverside. Their bite is extremely painful and, while an antivenin (a.k.a. anti-venom) exists now, before it was discovered, about 5 percent of bitten people died.
Think you can ID a black widow bite on sight? Not so fast: The actual bite looks a lot like any other spider bite. However, they do tend to become more swollen and red than your general household spider bite, he says.
Black widow spiders are tough to identify, as well. Only female black widows have the characteristic red hourglass-shaped markings on their backs. Male and immature black widows have tan and white stripes, Vetter says.
Because these types of bites are so serious, if you strongly suspect you were bitten by a black widow or you develop muscle cramping, abdominal and chest pain, high blood pressure, a racing heart, and/or vomiting within two hours of a bite, go to the ER immediately, Arnold says.
A post shared by Ashley Parsons (@ashley_parsons) on Jul 13, 2015 at 10:00am PDT
The brown recluse (also known as the fiddleback spider or violin spider) is one of the most venomous spiders in America, but they are limited to very specific geographic regions—if you don’t live in one of these places, it’s highly unlikely you need to worry about this type of bite, Vetter says. (Check out this map to see if you’re in the danger zone.)
And despite what you may have heard, even where brown recluses are present, they rarely bite, he adds. To identify a brown recluse, look for six eyes arranged in pairs. (Although getting close enough to see the eye pattern on a spider sounds, frankly, terrifying.)
Brown recluse bites do happen though, and when they do, they are often described by «sharp burning pain,» Arnold explains. Within several hours, the bite area becomes discolored and forms an ulcer that can takes several weeks to heal. In addition to the wound, individuals can also develop fevers, muscle aches, and in rare cases, severe anemia as a result of the venom.
Start by treating any bite at home with cold compresses and an antibiotic cream, but if you start to show severe symptoms, including a lot of swelling, increased pain, fever, spreading rash or other sign of infection, get medical attention immediately, he adds. There isn’t an antivenin, but they can treat the symptoms and manage the infection.
A post shared by Evan (@eplevinski) on Sep 13, 2013 at 8:52am PDT
The hobo spider is actually a pretty common venomous house spider in the U.S., but despite some scary media reports, they’re not aggressive and will only bite if provoked, according to the U.S. Forest Service. In addition, about half of hobo spider bites are «dry,» meaning they contain no venom, the service adds.
If you do receive a venomous bite, within a few hours it will become red and hard, similar to a mosquito bite, and within a day or two will develop blisters. After the blisters open, a scab typically forms along with a rash that often looks like a target or bull’s eye.
Because these wounds can become necrotic (as in, infected to the point they start killing surrounding tissue) and can last for years in some cases, you should see a doctor immediately, Arnold says. There isn’t an antivenin but they can treat the symptoms and manage any infection with antibiotics.
Hobo spiders can be hard to identify, according to the Forest Service. They are large and often have chevron-type markings on their backs, but these won’t be visible on darker-skinned adult spiders, which is why it’s important to get any bite checked out if it starts to show signs of infection or you see a target forming on your skin, Arnold says.
A post shared by Chrissy (@porcelainbones84) on Mar 24, 2013 at 11:47am PDT
Tarantulas may look big and scary, but most of the North American varieties are pretty chill. And even while the bite itself can be painful, the venom is fairly benign and likely won’t cause long-term issues, Arnold says. Like most spider bites, tarantula bites can cause some swelling, itching, and irritation.
However, he adds, tarantulas also have the ability to flick hairs off of their body and into your skin, which can be very irritating and painful. And some people are allergic to tarantula venom, which can make the bite even more inflamed, according to the National Institutes of Medicine.
Most of the time, it’s fine to try treating these at home by washing the site, applying ice, and taking ibuprofen, he says. But if you find yourself having a more extreme reaction, including symptoms like rapid heart rate or difficulty breathing, get to the emergency room.