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Spiders that sting: Identifying and Treating Spider Bites

by alexxlab

Identifying and Treating Spider Bites

By Markham HeidMedically Reviewed by Mohiba Tareen, MD

Reviewed:

Medically Reviewed

Spider bites can look very different from person to person, and much also depends on the type of spider.Leonardo Briganti/Alamy

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 most of the skin issues people pin on spiders are actually other types of bug bites or skin issues, he says.

Other researchers back Vetter up on this. “Spider bites are really rare,” says Jonathan Day, PhD, a professor emeritus 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.

RELATED: Everything You Need to Know About Bug Bites and Related Diseases

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 pimple-like 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:

  1. Clean the bite with soap and water.
  2. Swab the bite with alcohol to prevent infection, Dr. Day recommends.
  3. 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.

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Editorial Sources and Fact-Checking

  1. Spider Bites. MedlinePlus. August 9, 2014.
  2. Types of Venomous Spiders. Centers for Disease Control and Prevention. May 31, 2018.
  3. Brown Recluse Spider. MedlinePlus. July 20, 2021.
  4. Brown Recluse Spider. Entomology at the University of Kentucky. July 12, 2018.
  5. Black Widow Spider. MedlinePlus. July 20, 2021.
  6. Spider Bites: First Aid. Mayo Clinic. June 11, 2021.

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Spider bites – Symptoms & causes

Overview

Spider bites are usually harmless, and spiders don’t usually bite unless threatened.

Spider bites can cause redness, pain and swelling, or you might not notice them at all. Many other bug bites and skin sores cause redness, pain and swelling. So unless you actually saw a spider bite you, it’s difficult to be certain that your wound was caused by a spider.

Worldwide only a few species of spiders have fangs long enough to penetrate human skin and venom strong enough to hurt humans. Among these are widow spiders, with about 30 species, and recluse spiders, with more than 140 species worldwide.

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Symptoms

Typically, a spider bite looks like any other bug bite — a red, inflamed, sometimes itchy or painful bump on your skin — and may even go unnoticed. Harmless spider bites usually don’t produce any other symptoms.

Many skin sores look the same but have other causes, such as a bacterial infection.

Bites from some spiders, such as widow spiders and recluse spiders, might cause serious signs and symptoms.

Widow spider bites

Signs and symptoms of a widow spider bite can include:

  • Redness, pain and swelling. You might have pain and swelling around the bite, which can spread into your abdomen, back or chest.
  • Cramping. You might have severe abdominal rigidity or cramping, which is sometimes mistaken for appendicitis or a ruptured appendix.
  • Nausea, vomiting, tremors or sweating. You might experience nausea, vomiting, tremors or sweating alone or in combination.

Symptoms can last 1 to 3 days.

Recluse spider bites

Signs and symptoms of a recluse spider bite can include:

  • Increasing pain over the first eight hours after the bite
  • Fever, chills and body aches
  • A bite wound with a pale center that turns dark blue or purple with a red ring around it
  • A bite wound that grows into an open sore (ulcer) with the skin around it dying

When to see a doctor

Seek medical care immediately if:

  • You were bitten by a dangerous spider, such as a widow or recluse.
  • You’re unsure whether the bite was from a dangerous spider.
  • You have severe pain, abdominal cramping or a growing wound at the bite site.
  • You’re having problems breathing or swallowing.
  • The area of the sore has spreading redness or red streaks.

Causes

Severe spider bite symptoms occur as a result of the venom that the spider injects. Symptom severity depends on the type of spider, the amount of venom injected and how sensitive your body is to the venom.

Risk factors

Risk factors for spider bites include living in areas where spiders live and disturbing their natural habitat. Widow spiders and recluse spiders like warm climates and dark, dry places.

Widow spider habitat

Widow spiders can be found throughout the United States, except Alaska, and are more common in the rural South. They’re also found in Europe. They are more active in the warmer months and prefer to live in:

  • Sheds
  • Garages
  • Unused pots and gardening equipment
  • Woodpiles
  • Closets and cupboards during cold weather

Recluse spider habitat

Recluse spiders are found most commonly in the southern half of the United States and in South America, where they are known as brown spiders. These spiders are so named because they like to hide away in undisturbed areas. They are most active in the warmer months. Indoors, they prefer to live:

  • In cluttered basements and attics
  • Behind bookshelves and dressers
  • In rarely used cupboards

Sometimes they get mixed up in bed linens and clothing, causing many bites to occur in the early morning.

Outside, they seek out dry, dark, quiet spots, such as under rocks or in tree stumps.

Complications

Rarely, a bite from a widow spider or recluse spider is deadly, particularly in small children.

A severe wound from a recluse spider can take weeks or months to heal and leaves large scars.

Prevention

Spiders usually bite only in defense, when being trapped between your skin and another object.

To prevent spider bites:

  • Learn what dangerous spiders look like and their preferred habitats.
  • Wear a long-sleeved shirt, hat, long pants tucked into socks, gloves and boots when handling stored boxes or firewood and when cleaning out sheds, garages, basements, attics and crawl spaces.
  • Inspect and shake out gardening gloves, boots and clothing before use.
  • Use insect repellents, such as DEET. Carefully follow directions on the package.
  • Keep insects and spiders out of the house by installing tightfitting screens on windows and doors, sealing cracks where spiders can come in, and using safe indoor insecticides.
  • Reduce debris or remove piles of rocks or lumber from the area around your home and avoid storing firewood against the walls of your home.
  • Make sure beds aren’t pushed against the wall and that only the legs of the bed touch the floor. Don’t store items under the bed and don’t let bedding drag on the floor.
  • Remove spiders and spiderwebs from your home.
  • If a spider is on your skin, flick it off with your finger rather than crushing it against your skin.
  • When cleaning tarantula enclosures, wear gloves, a surgical mask and eye protection.

ERR overview: which insects and arachnids are willing to bite and sting the people of Estonia | Ecology

Summer in Estonia is not complete without a can of spray against annoying insects. Mosquitoes, horseflies, ticks and midges are not the only representatives of the local fauna, lying in wait for their prey or even chasing it. The editors of the ERR portal decided to find out which insects and arthropods pose a danger to humans. The topic is commented by the biologist of the Museum of Nature Katerina Pesocki.

Some insects have been familiar to Estonians since early childhood and usually evoke only positive emotions. A prime example of this is the ladybug. The reddish-orange insect of the ladybug family, or coccinellids – the seven-spotted ladybug – immediately catches the eye and is usually perceived as the cutest creature. People often pick it up to take a picture or see how spectacularly the insect will take off from their finger. But there is also an unexpected turn when the ladybug bites.

The seven-spotted ladybug is able to use its mouthparts to bite a person, among other things. Author: Pixabay

Although this small insect is not capable of biting the skin to blood, an unexpected bite can still scare a person. How is it that such a cute insect suddenly bites? The fact is that many representatives of arthropods, especially those with a gnawing type of mouth apparatus, are quite capable of using their weapons, including for self-defense purposes.

Common earwig. Terrible in appearance, but does not bite. Posted by Melani Marfeld / Pixabay

It also happens that not only the jaws, but also various outgrowths on the body can serve as means of self-defense. For example, there are such interesting insects as earwigs. At the end of their elongated body, on the last segment of the abdomen, there are processes called forceps. The insect uses them perfectly, like tongs. They can also be used in self-defense, although often the insect simply frightens by demonstrating its formidable weapon.

Spiders: there are no extremely dangerous spiders in Estonia, but the bite of some can be painful

Defending themselves, not only insects can bite, but also, for example, spiders.

All spiders living in Estonia are predatory “comrades” (lead a predatory lifestyle), and their adaptations are appropriate. Spiders have mouth appendages, chelicerae, and venom ducts that they inject into the victim’s body. The venom of the spiders living in Estonia is not lethal to us, but the bite of large spiders with fairly strong chelicerae can be painful. The bite of some single species can cause redness on the skin, swelling and fever. However, there are no spiders living in Estonia whose venom is extremely dangerous.

In Estonia, there is a yellow-headed piercing spider. Its venom can cause nausea and fever. Author: Fritz Geller-Grimm/Wikipedia

All of the arthropods mentioned use their weapons exclusively for self-defense. Not a single ladybug would think of climbing on a sleeping person to bite him.

Hematophagous: pursue and attack

There are some representatives of arthropods that lead a parasitic lifestyle and are hematophagous, that is, their diet consists of blood. They pursue prey and actively attack.

Some have adapted so effectively to a parasitic way of life that they live with their potential victims: bed bugs and lice with humans, fleas with dogs.

Fleas, bed bugs and louse prefer to coexist with their prey. Author: collage

Other representatives of hematophagous arthropods prefer to live in nature and patiently wait for a meeting with their prey. Among arachnids, these are, of course, ticks.

Ixodid ticks in Estonia

If a person doubts whether a tick is crawling on him, then you can count the limbs: a tick with a flat brownish body has eight limbs. Different types of ticks live in Estonia, of which two species parasitize humans: the taiga tick and the dog tick. The name of the latter does not mean that it is found only in dogs.

The dog tick carries diseases such as Lyme disease, encephalitis, Marseilles fever. Author: Erik Karits / Pixabay

It should be understood that ticks do not fall from trees like pine cones. They wait for their prey on low plants. According to my personal observations, there are more ticks in 2020 than in the past. This was facilitated by a warm winter.

If ixodid ticks are waiting for their prey, sitting in ambush, on some relatively long blade of grass, trying to catch the approach of the desired object with the help of receptors, then some insects have to actively move in search of their prey.

Mosquitoes and their relatives – midges and midges

Everyone knows how piercing the mosquito squeak sounds at night, when the insect flies in the silence of the room above the ear in search of access to blood. There are over 1200 species of mosquitoes in Estonia, but don’t worry – not all of these species feed on blood. There are three families: blood-sucking mosquitoes, midges and midges. They use blood, including human.

The female mosquito needs blood to continue offspring. Author: Pixabay

About 30 species of mosquitoes “drink” human blood. Most of them parasitize humans in the warm season, but there are exceptions, such as the basement mosquito. Such an insect in nature can be found in warm countries. Once in Estonia, this species has adapted to breed in damp basements, and the cold winter does not bother it. Usually, blood-sucking mosquitoes that breed in the nature of our country are active from spring to late autumn. Among blood-sucking mosquitoes, as you know, females “drink” blood, they need it for the development of germ cells and laying eggs.

Mosquitoes’ relatives include midges and midges.

Biting midges are one of the smallest blood-sucking parasites among insects, they are no more than 3 mm in length. These insects begin to fly actively around the time of cherry blossom, but become especially annoying by the beginning of July. It is the females who consume the blood, their bites are painful and cause redness on the skin. There are about 20 species of biting midges in Estonia.

Female midge. Author: Wikipedia

Among the bloodsuckers there are also smaller representatives – midges. The species diversity of midges in our country is also within 20 species. Their saliva causes intense itching.

Deer bloodsuckers, gadflies and blueberry calyptera

In addition to mosquitoes and their relatives, various flies show interest in blood. One family of insects is called the bloodsuckers.

The most famous representative of the bloodsucker in our country is the deer bloodsucker, more often it is called the moose fly. You can meet them in those forests where moose, deer, roe deer and wild boars live. In dry forests without succulent vegetation, and therefore without food for elk and deer, these flies are not found. Most often, a fly crawls over its prey without wings. The fact is that when she lands on her food object, she gets rid of her wings forever.

Deer bloodsuckers are confused with ticks because, once on the body, they shed their wings. Author: Flickr

In addition to deer bloodsuckers and other flies, the well-known gadflies also belong to the short-whiskered suborder. If you tell a child that a horsefly is a large fly, with big eyes and a desire to taste blood, this will not be a lie.

The horsefly has really big eyes to see its prey. Although horseflies are good flyers and can easily fly a couple of kilometers, they still do not fly far from the reservoir. Horse flies are usually active from late May to mid September. The greatest activity is achieved on hot summer days, in cloudy and rainy weather the activity of horseflies decreases. Females feed on blood, males consume plant foods.

Houseflies do not bite

Our harmless housefly has a close relative in the family – the autumn stinger, about 5-7 mm in length. Some people might think that these are house flies “go crazy” by autumn and start biting people, but no. Closer to autumn, it is not at all house flies that attack, but autumn zhigalki. These insects can attack not only in nature, but also indoors. So the housefly bite is a myth.

Autumn Stinger attacks mainly animals, but does not disdain people either. Author: Pavel Krok/Wikipedia

In addition to representatives of the order Diptera, which was discussed earlier, sometimes some representatives of Lepidoptera present surprises. A harmless butterfly is not associated with vampires, and meanwhile, among Lepidoptera there are such species, the diet of which, among other things, includes blood. Although the calyptra cornflower is found in our country, cases of this butterfly attacking a person are very rare, because blood is not the main diet of this insect.

The attack of the calyptra basilis on a person is a rarity. Author: Dumi/Wikipedia

scientist spoke about dangerous species of spiders in the Volgograd region

Articles

3 Jul 16:18, 4 photos

These small representatives of the fauna begin to show activity in the region from May, and end in autumn.

The hot climate of the Volgograd region is not only a certain temperature discomfort for its inhabitants. The lack of heavy rains creates a favorable environment for the appearance of poisonous spiders. Many of the arthropod fauna have successfully migrated from neighboring Kazakhstan. The other day, in social networks, Volgograd residents shared messages that they had met a salpuga in nature, which they had never seen in these places before. Karakurts generally become almost an ordinary phenomenon for local residents, but at the same time no less dangerous. So, in May, a resident of the Novoanninsky district “boasted” that he had discovered a poisonous spider in the courtyard of his house. Fortunately, no one was hurt. The poison of the karakurt is painful and deadly, it is 17 times stronger than the poison of a rattlesnake. As they say, evaluate the odds.

Elena Ivantsova, doctor of agricultural sciences, professor, director of the Institute of Natural Sciences of the Volgograd State University, told Gorodskiy Vesti what spider species dangerous to humans live in the Volgograd region.

– Karakurt is the most dangerous species of spiders for humans, living in hot arid conditions of the Volgograd, Astrakhan regions, Kalmykia, Dagestan and the east of the Rostov region, – says the professor. – Directly on the territory of the city of Volgograd, the population of karakurt was noted from the end of 90s, but is not observed every year, but usually during outbreaks of the species.

The body of poisonous spiders is spherical. The female karakurt is much larger than the male, her body with a span of legs in length is approximately 2.5 cm, male individuals are much smaller – only 6-7 mm. Four pairs of limbs are located on both sides of the body. Two pairs of middle tarsi covered with hairs. The first and last pairs are distinguished by the greatest length. The color of spiders is distinguished by the presence of red or orange spots of various shapes. Sometimes a white border of each spot is added to the pattern on the body.

– The venom of a female spider can be fatal. After a bite, burning pain after 15-20 minutes spreads to neighboring parts of the body and organs, then, after 20-40 minutes, a burning sensation appears throughout the body, chills, weakness, mental arousal develops. The pulse becomes frequent, breathing is difficult, heart sounds are muffled; blood pressure initially rises. Some patients experience salivation and difficulty swallowing. After 2-3 hours, cramps of the lower and upper extremities appear. Later, nausea, vomiting, tension of the rectus abdominis muscles and constipation, puffiness of the face, swelling of the eyelids and heavy sweat, which is combined with chills, appear. The temperature is subfebrile from the norm to 38 ° C, less often normal or high. When bitten by a karakurt, you must immediately seek help from the nearest medical facility or call an ambulance, warns Elena Ivantsova.

In addition to karakurt, two types of tarantulas are considered dangerous for humans: South Russian and huge. Tarantulas are one of the largest spiders in the Volgograd region, reaching sizes up to 3 cm without legs and up to 6 cm with legs. The development cycle of individuals of both species reaches up to four years; in the first year after birth, spiders lead a wandering lifestyle, and in the second year they build burrows where they hide from predators and wait for prey running past.

Despite the reputation, the danger to humans from tarantulas is greatly exaggerated. The tarantula will in any case prefer to run away or warn with a threatening posture before launching the chelicerae.

– The venom of a tarantula is comparable in strength to that of a wasp, however, the amount of this poison is much greater than that of a wasp, that is, the feeling after a spider bite is comparable to the feeling from a bite of two or three wasps. Two punctures will be visible at the bite site, then swelling and redness of the skin appear, accompanied by burning and itching, and a short-term increase in temperature is possible. People who do not suffer from allergies do not need special treatment, Professor Ivantsova comments.

Help will be to wash the wound surface as soon as possible. Clean running water is suitable for washing, which will avoid infection. You can use soapy water. It is advisable to treat the wound with an antiseptic – hydrogen peroxide, chlorhexidine, if such medicines are at hand. In order to relieve swelling, you can use a cold compress from ice or another product that is in the freezer.

However, if symptoms of an allergic reaction are observed, medical attention should be sought immediately. Otherwise, a severe allergic reaction can be fatal.

Southern Russian tarantula is outwardly distinguished by the following features: body color varies from dark sand to dark brown, almost black. There are 6 pairs of lighter spots on the upper side of the abdomen. The whole body is covered with dense hairs. Legs with numerous spines, which are not very noticeable surrounded by hairs. The underside of the body is intensely black. The abdomen is oval, in size the female is slightly larger than the cephalothorax, and the male is slightly smaller. The legs are of medium length (approximately equal to the length of the body) and thick compared to spiders from other families.

Huge Tarantula – this is the name of another dangerous spider – in size, shape and body proportions it is very similar to the South Russian one, but it differs significantly in color. It varies within shades of grey. On the abdomen there is a rather complex leaf-like pattern. The cephalothorax and legs are colored like those of the South Russian tarantula, but the abdomen is very different. In young animals it is orange and there is a black dot in its center. With age, this point increases in size and, by reaching its maximum size, occupies almost the entire abdomen. Thus, in an adult spider, the abdomen turns out to be black from below, and orange spots remain in front and behind.

It is possible to prevent a tarantula attack, the scientist says. To do this, you need to follow a number of the following rules: while on vacation, avoid places where there are a large number of various cracks in the ground, dead wood and stones; close the tent at night; while in the country or in a tent, constantly inspect your shoes for spiders or other insects in them.