What Will Happen If A Spider Bites You?
Spider Bites: What You Should Know
- 1 Spider Bites: What You Should Know
- 2 Symptoms of Spider Bites
- 3 Diagnosis
- 4 Treatment
- 5 Prevention
- 6 First Aid: Spider Bites
- 7 More on this topic for:
- 8 How to Know When a Spider Bites and What to Do About It
- 9 Identifying a Spider Bite: What Does One Look Like?
- 10 Spider Bites Usually Heal on Their Own. Here’s When to Seek Medical Attention
- 11 Why Do Spiders Bite People?
- 12 Spider-Man: 5 Weird Effects of Real Spider Bites
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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First Aid: Spider Bites
Because most spider bites don’t go all the way through skin, they usually cause only mild reactions. However, black widow and brown recluse spider bites can cause serious reactions and need immediate care. Allergic reactions to spider bites can happen but are rare.
Signs and Symptoms
Of a brown recluse spider bite:
- swelling or redness around the bite
- pain around the bite within 2 to 8 hours
- joint stiffness or pain
- nausea, vomiting
- body rash
- fever, chills, and body aches
Of a black widow spider bite:
- painful muscle cramps within 8 hours
- no bite on the skin (or only a small bite)
- belly pain and stiffness
- nausea and vomiting
- breathing trouble
Of an allergic reaction:
- swelling of the face or mouth
- difficulty swallowing or speaking
- chest tightness, wheezing, or trouble breathing
What to Do
If your child has been bitten by a spider:
- Wash the area with soap and water.
- Put an ice pack or a cool wet cloth on the bite area to relieve pain and swelling.
Get Medical Care Right Away if:
- Your child has any signs of an allergic reaction.
- Your child develops any kind of rash after a bite.
- Your child has severe pain or cramping.
- The area begins to look infected (increasing redness, pain, swelling, warmth, or pus).
- You think your child was bitten by a brown recluse spider or black widow spider.
- Make sure garages, attics, and woodpiles are free of spider webs.
- Make sure kids wear long sleeves and pants when playing around garages, attics, and woodpiles, etc.
- Firewood should be kept outside the house to avoid bringing spiders inside.
More on this topic for:
Note: All information on KidsHealth® is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
© 1995- The Nemours Foundation. All rights reserved.
How to Know When a Spider Bites and What to Do About It
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-Man: 5 Weird Effects of Real Spider Bites
Although Spider-Man got his superhero abilities from a spider bite, ordinary spider-bite victims may have to deal with spider-bite effects that have nothing to do with being able to scale walls and climb around on ceilings.
Some of the weirdest effects that spider venom may have on regular, nonsuperhero humans include unwanted erections, dead skin tissue that turns black, unusual rashes, dark pee and sweat so heavy it makes puddles on the floor.
However, it is important to remember that such unusual symptoms are extremely rare, and the vast majority of spider bites are harmless, or cause only mild irritation and itchiness. [In Photos: The Science of the Amazing Spider-Man 2]
In fact, spiders do not often bite people, and if they do, it is because they feel threatened. Black widow spiders and brown recluse spiders are the only two spider species in North America whose bites may sometimes result in symptoms more serious than minor local pain and swelling, according to Rick Vetter, a retired arachnologist at the University of California, Riverside.
Although hobo spiders, which are common in the Pacific Northwest, are also listed by the Centers for Disease Control and Prevention as one of the three types of spiders that can be toxic to people, some researchers have argued that hobo-spider venom may not be so toxic after all.
Here are some of the weirdest effects spider bites have had on people.
The Brazilian wandering spider’s venom contains a toxin whose unusual erection-inducing qualities have attracted the attention of the pharmaceutical industry. In 2007, researchers found that the bites of the Brazilian wandering spider can cause long and painful erections in human males, along with other symptoms. The effect happens because the spider’s venom raises the levels of nitric oxide, which is a chemical that increases blood flow.
Researchers have since tested the toxin that is responsible for this unusual effect, called PnTx2-6, in the hope of developing a potential new drug for erectile dysfunction.
The Brazilian wandering spider is large, with a body size reaching up to 2 inches (5 centimeters) and leg spans stretching 5 or 6 inches (13 to 15 cm). Although the creepy crawler’s size may make it look threatening, it is not aggressive and, like most spiders, will only attack when it feels threatened, experts say.
Although there have been cases of «necrotic arachnidism,» in which spider venom kills human tissue, such cases are extremely rare. In fact, researchers estimate that less than one case of dead human tissue is reported per 5,000 spider bites from verified spider specimens, and verification of spider bites is very rare, Dr. Scott Weinstein, a toxinologist at Women’s and Children’s Hospital in North Adelaide, South Australia, told Live Science. (Toxinology is the study of the venoms and poisons of plants, animals and microbes; it is different from toxicology, which is the study of chemicals and drugs as they affect the body.)
If a spider bite is «verified,» it means that there was actual evidence that a person was bitten by a particular kind of spider. The only spider in North America whose bites have been shown to kill human tissue in rare instances is the brown recluse spider, Vetter said.
When necrosis does occur, tissue may sometimes turn black as cells die. One such case was reported last year — a woman on vacation in Italy developed necrosis in her ear after being bitten by a brown recluse spider. Part of her ear turned black, and her doctor had to remove the dead tissue and restore it, using cartilage from the woman’s ribs.
Some people develop unpredictable skin reactions to spider bites. A 66-year-old patient in France developed a strange rash after being bitten by a spider, which the doctors suspected was likely a brown recluse spider, according to a report of his case. The man had pinhead-size bumps on his forearms, which later spread to other parts of his body.
The medical staff diagnosed the man with a condition called acute generalized exanthematous pustulosis (AGEP), which typically occurs in people taking antibiotics. Other reports have also linked AGEP to brown recluse spider bites, the researchers said. The man recovered in five days, after doctors treated him with oral corticosteroids.
Unusual blood disorders and dark pee
In the case of the man in France who developed the strange rash, the doctors also found that he had a blood disease called periarteritis nodosa (PAN), in which small arteries become swollen and damaged. The doctors linked his blood condition with the brown recluse bite, because previous reports had described conditions similar to PAN in animals injected with brown recluse spider venom.
In fact, blood disorders are some of the rare symptoms that occur in people who have been bitten by recluse spiders, Vetter wrote in one study. The brown recluse venom may cause red blood cells to burst and release their contents into plasma, in a process called hemolysis. As a result, anemia may develop and can last from four to seven days, he said.
These blood problems may lead to other symptoms, such as acute kidney injury and jaundice (yellowing of the skin), as the blood protein called hemoglobin breaks down. The waste products of the breakdown can build up in the blood, and turn the urine dark when they are then excreted.
Puddles of sweat
Some Australian widow spider bite victims have been found to sweat so much after getting bitten that their sweat formed puddles on the floor, Vetter reported in one study.
Excessive sweating is one of the symptoms that may result from the bites of certain spiders that affect the nervous system. The venom of the black widow, for instance, attacks nerves by blocking their signals to the muscles. This causes the muscles to contract repeatedly, which can be painful and stressful for the body.
Black widow spider bite victims may also experience other nerve-related symptoms, such as high blood pressure, restlessness and severe facial spasms.
Who gets these spider-bite symptoms?
Whether a spider bite affects a person only mildly or causes severe symptoms depends on a number of factors, such as the amount of the venom injected, and the size and age of the person who got bitten. Children and elderly people are particularly susceptible to extreme symptoms from toxic spider bites.
However, most people who get bitten are highly unlikely to experience these severe symptoms, researchers say.
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