What are the most dangerous spiders in the United States. How to identify a spider bite. What are the symptoms of a widow spider bite. How to treat a brown spider bite. When to seek medical attention for a spider bite. How to prevent spider bites at home.

The Most Dangerous Spiders in the United States

While almost all spiders are venomous, only a few species in the United States pose a significant threat to humans. The two types of spiders responsible for most serious injuries are:

• The widow spider (including the black widow)
• The brown spider (also known as the brown recluse, fiddleback, or violin spider)

Brown spiders are primarily found in the Midwest and South Central United States, while widow spiders are present throughout the country. Despite their fearsome reputation, tarantulas are not considered dangerous to humans, as their bites rarely cause serious harm.

Identifying Spider Bites and Their Symptoms

It’s important to note that identifying a spider bite based solely on the bite mark is not possible. A definitive diagnosis can only be made if the spider is captured and identified. However, understanding the symptoms associated with bites from dangerous spiders can help in recognizing potential threats.

Widow Spider Bite Symptoms

A widow spider bite typically causes:

• Initial sharp pain, similar to a pinprick
• Dull, sometimes numbing pain around the bite area
• Severe cramping pain and muscle stiffness in the abdomen, shoulders, back, or chest
• Nausea and vomiting
• Sweating and restlessness
• Anxiety and headache
• Drooping and swelling of the eyelids
• Rash and itching
• Breathing difficulties
• Increased saliva production
• Weakness

Brown Spider Bite Symptoms

A brown spider bite may cause:

• Little or no immediate pain
• Pain developing within an hour around the bite area
• Severe pain affecting the entire injured area
• Redness, bruising, and itching
• Formation of a blister surrounded by a bruised or bull’s-eye-like red area
• Enlargement and rupture of the blister, forming an open sore (ulcer)
• Development of a thick black scar (eschar)

In rare cases, brown spider bites can lead to more severe symptoms such as nausea, vomiting, aches, fatigue, chills, sweating, blood disorders, and kidney failure.

Treatment Options for Spider Bites

The treatment for spider bites varies depending on the type of spider and the severity of the symptoms. Here are the general approaches for treating widow and brown spider bites:

First-Aid Measures for All Spider Bites

1. Clean the wound thoroughly
2. Apply ice to reduce pain (wrap ice in a thin cloth to avoid direct skin contact)
3. Elevate the affected limb if the bite is on an extremity

Treating Widow Spider Bites

For widow spider bites, treatment may include:

• Benzodiazepines to relieve muscle pain and spasms
• Opioid analgesics for pain management
• Antivenom for severe cases or those with moderate symptoms like muscle cramping

Hospitalization is often required for individuals under 16 or over 60 years of age, those with high blood pressure or heart disease, and anyone experiencing severe symptoms.

Treating Brown Spider Bites

Most brown spider bites heal without complications. Treatment typically involves:

• Daily cleaning of the wound with a povidone-iodine solution
• Soaking the affected area in sterile salt water (saline) three times a day
• In some cases, surgical wound repair may be necessary

When to Seek Medical Attention for Spider Bites

While many spider bites can be treated at home, certain situations require immediate medical attention. Seek professional help if:

• You experience severe pain, muscle cramping, or difficulty breathing
• The bite area develops a large, open sore or black eschar
• You notice signs of infection, such as increased redness, warmth, or pus
• You develop systemic symptoms like fever, chills, or body aches
• You have a known allergy to spider venom
• The person bitten is a young child, elderly, or has a weakened immune system

Preventing Spider Bites at Home and Outdoors

Taking preventive measures can significantly reduce the risk of spider bites. Here are some tips to keep spiders at bay:

Indoor Prevention

• Keep your home clean and clutter-free
• Seal cracks and crevices in walls and floors
• Use screens on windows and doors
• Shake out clothing and shoes before wearing
• Inspect bedding and towels before use

Outdoor Prevention

• Wear long sleeves and pants when working in areas where spiders may be present
• Use gloves when gardening or handling firewood
• Avoid leaving shoes or clothing outside overnight
• Keep woodpiles and debris away from your home
• Use caution when reaching into dark corners or crevices

Distinguishing Spider Bites from Other Skin Conditions

Many skin conditions are often mistaken for spider bites, some of which can be more serious. These include:

• Bacterial infections, such as methicillin-resistant Staphylococcus aureus (MRSA)
• Allergic reactions
• Insect bites from other arthropods
• Skin abscesses
• Certain skin disorders like dermatitis or eczema

If you’re unsure about the cause of a skin lesion or wound, it’s best to consult a healthcare professional for an accurate diagnosis.

The Impact of Spider Bites on Public Health

While spider bites can be concerning, it’s important to put their impact on public health into perspective. In the United States:

• Spider bites cause fewer than three deaths per year
• Most fatalities occur in children
• Serious injuries from spider bites are relatively rare

This low mortality rate is due to a combination of factors, including the limited distribution of dangerous spider species, effective medical treatments, and increased public awareness about spider bite prevention and management.

Advancements in Spider Bite Treatment and Research

The field of arachnology and medical research continues to advance our understanding of spider venom and improve treatment options for bites. Some recent developments include:

Antivenom Improvements

Researchers are working on developing more effective and safer antivenoms for both widow and brown spider bites. These new antivenoms aim to reduce side effects and improve overall treatment outcomes.

Venom-Based Medications

Scientists are exploring the potential medical applications of spider venom components. Some spider toxins show promise in treating conditions such as chronic pain, cardiac arrhythmias, and even certain types of cancer.

Diagnostic Tools

New diagnostic techniques are being developed to help identify spider bites more accurately. These tools could help differentiate spider bites from other skin conditions, leading to more targeted and effective treatments.

Public Education Initiatives

Increased efforts in public education about spider identification, bite prevention, and proper first aid are helping to reduce the incidence and severity of spider bite cases.

As research progresses, we can expect to see further improvements in the prevention, diagnosis, and treatment of spider bites, ultimately leading to better outcomes for those affected by these potentially dangerous encounters.

Spider Bites – Injuries and Poisoning

By

Robert A. Barish

, MD, MBA, University of Illinois at Chicago;

Thomas Arnold

, MD, Department of Emergency Medicine, LSU Health Sciences Center Shreveport

Reviewed/Revised Jun 2022 | Modified Sep 2022

VIEW PROFESSIONAL VERSION

Topic Resources

Almost all spiders are venomous. However, the fangs of most species are too short or too fragile to penetrate human skin. Although at least 60 species in the United States have been implicated in biting people, serious injury occurs mainly from only two types of spiders:

• The widow (black widow) spider

• The brown (brown recluse, fiddleback, or violin) spider

Brown spiders are present in the Midwest and South Central United States, not in the coastal and Canadian border states, except when imported on clothing or luggage. Widow spiders are present throughout the United States. Although some people consider tarantulas dangerous, their bites do not seriously harm people. Spider bites cause fewer than three deaths a year in the United States, usually in children.

PODCAST

• Serious injuries from spider bites can include severe wounds caused by the tissue-destroying venom of brown spiders and bodywide poisoning caused by the nerve-toxic venom of widow spiders.

• Wounds suspected of being caused by the brown spider are often caused by other problems, some potentially more serious.

• Brown spider bites are treated by caring for the wound.

• Widow spider bites are treated by relieving symptoms and sometimes giving antivenom.

(See also Introduction to Bites and Stings Introduction to Bites and Stings Many creatures, including humans, bite when frightened or provoked. Others include Alligators and crocodiles Iguanas Mites Ticks read more . )

The bite of a widow spider usually causes a sharp pain, somewhat like a pinprick, followed by a dull, sometimes numbing, pain in the area around the bite. Cramping pain and muscle stiffness, which may be severe, develop in the abdomen or the shoulders, back, and chest. Other symptoms may include nausea, vomiting, sweating, restlessness, anxiety, headache, drooping and swelling of the eyelids, rash and itching, severe breathing problems, increased saliva production, and weakness.

Did You Know…

The bite of a brown spider may cause little or no immediate pain, but some pain develops in the area around the bite within about an hour. Pain may be severe and may affect the entire injured area, which may become red and bruised and may itch. The rest of the body may itch as well. A blister forms, surrounded by a bruised area or by a more distinct red area that resembles a bull’s-eye. Then the blister enlarges, fills with blood, and ruptures, forming an open sore (ulcer) followed by a thick black scar (eschar) that may leave a large crater-like scar. Uncommonly, nausea and vomiting, aches, fatigue, chills, sweating, blood disorders, and kidney failure develop.

There is no way to identify a particular spider on the basis of its bite mark. Therefore, a specific diagnosis can be made only if the spider can be identified. Widow spiders are recognized by a red or orange hourglass-shaped marking on the abdomen. Brown spiders have a violin-shaped marking on their back. However, these identifying marks can be difficult to discern, and the spider is rarely retrieved intact, so the diagnosis is usually uncertain and based on symptoms. Many people mistake skin infections, some potentially serious (such as methicillin-resistant Staphylococcus aureus [MRSA] infections), or other disorders for spider bites.

• Cleaning the wound and applying ice

• For widow spider bites, drugs to relieve pain and muscle spasms and often antivenom

• For brown spider bites, wound care and sometimes surgical wound repair

First-aid measures for a spider bite include cleaning the wound, applying ice (for example, an ice cube or crushed ice in a plastic bag and wrapped in a thin cloth because ice should not be applied directly on the skin) to the bite to reduce pain, and, if the bite is on an extremity, elevating the wound site.

For a widow spider bite, muscle pain and spasms can be relieved with benzodiazepines (which sedate and may help relax muscles) and opioids (analgesics). Antivenom is given for severe and sometimes for moderate symptoms such as muscle cramping or other bodywide symptoms. Hospitalization is usually required for people younger than 16 or older than 60 and for people with high blood pressure, heart disease, or severe symptoms.

Did You Know…

Most brown spider bites heal without complications. Sores should be cleaned daily with a povidone-iodine solution and soaked 3 times a day in sterile salt water (saline). Moderately to severely damaged wounds may require surgical procedures.

NOTE:


This is the Consumer Version.


DOCTORS:



VIEW PROFESSIONAL VERSION

VIEW PROFESSIONAL VERSION

Copyright © 2023 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved.

Test your knowledge

Take a Quiz!

How to identify insect bites with bruising

by Alexis Rohlin / in Health

Insect bites that cause you to bleed under your epidermis, or the top layer of your skin, will cause bruises to form. There are several types of insect bites that may form bruises, such as bites from spiders, mosquitoes, bed bugs and ticks. Stings from scorpions, wasps or bees may also form bruises. Insect bites that cause bruises have a very distinct look to them. Once you learn what to look for, you will be able to identify an insect bite with bruising.

• Insect bites that cause you to bleed under your epidermis, or the top layer of your skin, will cause bruises to form.

Look for tiny red or white puncture marks in the centre of your bruise. If a spider bit you, there will be a pair of puncture marks. A single puncture mark can be made by a mosquito, bed bug or tick. Insect bites with bruising typically do not develop a red, raised, irritated and itchy lump around the bite.

Inspect the colour of your skin around the bite. Is it purple, red and yellowish or is it magenta or bright red? If your skin is a magenta or bright red bullseye or target shape, you have been bit by a tick and may have Lyme disease, which is a serious condition that needs to be treated with medication prescribed by a doctor. If the surrounding area of the bite is more muted pinkish-red colour that looks like a weal or oval shaped rash, it is not an insect bite with bruising, but a bed bug or mosquito bite. Bed bug bites are very painful. Mosquito bites irritate the skin and make it itchy.

• Inspect the colour of your skin around the bite.
• If your skin is a magenta or bright red bullseye or target shape, you have been bit by a tick and may have Lyme disease, which is a serious condition that needs to be treated with medication prescribed by a doctor.

Inspect your skin where you have located the insect bite to determine if it has caused bruising. An insect bite with bruising will have a ring of normal coloured skin around the bite surrounded by a larger ring-shaped bruise that is radiating out from it. The bruised area around the insect bite will be 1-inch or wider in diameter and will look like a doughnut.

If you aren’t sure what type of insect bit you, or if you are worried that what you see isn’t actually an insect bite with a bruise but some other form of injury, you should think about visiting your doctor and having him look at it.

Some bites with bruises are harmless and will disappear on their own, while other insect bites with bruising can turn into serious, life threatening bacterial infections. If the insect bite is very painful and the bruised skin turns brown or black or the bruised area spreads, go to the emergency room right away. These are signs that you have a staph infection. Staph is a common name for a type of flesh eating bacteria that can do immense damage to your body if it isn’t treated quickly.

Related

References

Author

• 1 Kids Health: Brown Recluse Spider
• 2 Bad Spider Bites: Staph Infection
• 3 Bad Spider Bites: Lyme Disease

What kind of insect bite leaves a bruise? – Drink-Drink

Insect bites are a fact of life, especially if you spend a lot of time outdoors. While allergies and other factors can lead to severe reactions, most insects tend to cause mild symptoms such as swelling and itching.

But bruising is possible depending on the bug and your individual reaction. Bruises can be caused by flying insects and beetles that can penetrate deep into your skin.

Learn more about the types of beetles that can cause bruising, what you should do, and how to identify the most common symptoms associated with certain beetles so you know when to seek medical attention.

Should I be concerned?

Bruising from a bug bite is not usually a cause for concern. Most bed bug bite symptoms go away on their own within a few days.

However, if you know you have been bitten by a certain type of insect, or if your symptoms get worse, you may need to see a doctor.

Insect bites that can cause bruising

The following types of bug bites sometimes cause bruising. Here’s what you need to know.

Hornets and wasps

Hornets and wasps stings are often painful.

After a bite, the affected area of ​​the skin may become red and swollen. It may also appear blue and purple due to injury.

These symptoms usually go away on their own within a few days without the need to see a doctor.

mosquitoes

Mosquitoes are perhaps best known for leaving small red bumps that are very itchy. Sometimes these bumps can also darken, giving the appearance of a bruise.

As with hornets and wasps, bruising from mosquito bites usually does not require medical attention.

Spiders

Some types of spider bites can also cause bruising, including poisonous ones such as the brown recluse or black widow spider.

With this type of bite, you will notice rings around the area in different colors, including red, blue, purple, and white. This is the result of skin necrosis from a poison that destroys skin tissue.

Venomous spider bites require immediate medical attention.

Ticks

Ticks burrow deep into the skin and must be carefully removed behind the head with tweezers.

If detected early, you may not notice any symptoms. Ticks can sometimes leave a red mark or bruise behind, which can also be swollen and itchy.

What other symptoms should I look out for?

In addition to bruising, a bug bite can also cause redness and swelling (inflammation).

These symptoms may be present even without bruising. Some insects, such as mosquitoes, can cause itching when they bite.

Most symptoms are minor and will disappear within a few days.

Signs of a more serious reaction

A beetle bite may cause more serious reactions. Seek immediate medical attention if you experience signs of anaphylaxis, a serious allergic reaction that can cause:

• difficulty breathing
• swelling of the face
• hives
• dizziness
• paleness
• confusion

You should also call your doctor if you experience symptoms of an infected insect bite, including:

• fever
• chills
• pus comes out of bite
• tumor that continues to grow without improvement
• red streak growing from the bite

How is a bedbug bite treated?

Your doctor will recommend home treatments to help relieve mild bed bug bites. Follow these steps for bruised insect bites:

1. First, wash the bed bug bite with plain soap and warm water. Blot (do not rub) dry.
2. Apply cold compresses or ice to the affected area for 15 minutes several times a day. This helps reduce pain and swelling. Repeat within 48 hours of the bug bite.
3. Rest and elevate the affected area if possible. This may help reduce swelling.
4. Switch to warm compresses after 48 hours to relieve pain. Repeat as often as needed.
5. If your doctor says everything is fine, take a pain reliever such as acetaminophen (Tylenol) or a non-steroidal anti-inflammatory drug (NSAID) such as ibuprofen.
6. Consider topical hydrocortisone cream or an oral antihistamine such as diphenhydramine (Benadryl) for itching. Follow all product directions carefully.

If you have a more severe bed bug bite, it is important to have your area checked by your doctor before trying to treat it yourself.

How to identify a bug bite?

If you don’t know which insect you are dealing with, you can make this determination based on the symptoms of your bite.

Here is a summary of the most common symptoms associated with common errors in the United States:

901 15 x

What complications are possible after a bug bite?

Serious bedbug bites can sometimes lead to the following complications:

• Infections. Fever, rash and pus at the bite site are all signs of infection. It is important to quickly eliminate a possible infection such as cellulitis.
• Lyme disease. Early symptoms of Lyme disease caused by tick bites may include fever and a rash that looks like a red bull’s-eye.
• Necrosis. This can happen in the case of brown recluse spiders, whose venom can kill healthy skin tissue and lead to long-term complications such as scars.
• Viruses transmitted by mosquitoes. These include West Nile virus, yellow fever, Zika virus and malaria.

A bruise by itself cannot be a sign of the above complications. That’s why it’s important to see a doctor if:

• you have a bite that won’t get better
• you have symptoms associated with a venomous spider or mite

What else can cause a bruise?

Bruises are caused by rupture of blood vessels caused by trauma to the body. Black, blue, or purple patches of skin are the result of a pool of blood under the skin.

Any type of injury or trauma can cause bruising. You may also be at risk of bruising based on:

• Your age
• Use of blood thinners
• bleeding disorders

Minor bruising usually does not require medical attention. Serious bruising caused by a more serious injury, such as a car accident, may need to be evaluated for underlying damage.

Other types of bruising that may require additional attention include bruising caused by broken bones or bleeding disorders.

Most bruises heal within 2 weeks, although more severe cases may take longer. See your doctor if your bruise doesn’t go away after 4 weeks, as this could be a sign of an underlying condition.

Conclusion

Bruising is just one of the many symptoms of a bug bite and is more common in some insects. In most cases, the disease is mild and treated at home.

Call your doctor or other health care provider if you have a severe reaction to a bed bug bite or if the bruise does not go away after a few days.

You should also seek medical attention if you suspect that your bites may have been caused by poisonous or disease-causing insects.

Do not go to Africa for a walk

You already know how to fight off a shark or escape from an army of zombies. But what if you met the most poisonous inhabitant on our planet? We found 10 most dangerous animals and estimated your chances of surviving after contact with them.

King Cobra

Exploring the impenetrable jungles and forests of India, South China, Malaysia, the Philippines and Indonesia, including the beloved Bali, is fraught with many dangers, and one of them may be a meeting with a king cobra. The snake is especially aggressive during the mating season. They are excellent tree climbers and swimmers, so the chances of getting away from her unnoticed are extremely small. King cobras usually do not waste poison “idle”, wasting it on tourists who accidentally wandered into their possessions, but if this did happen, then you will have about 15-20 minutes to save your own life.

Rescue. Only an antidote can help here, which is usually stored in local hospitals. Before arriving at the site, you can reduce the spread of poison through the body by pulling the bite site with a tourniquet.

Yellow scorpion

In fact, all representatives of the order of arthropods from the class of arachnids are considered dangerous, but the subspecies of leyurus quincestriatus has earned itself a reputation as the most dangerous in the world. You can meet him while traveling through North Africa, the Arabian Peninsula and the Middle East. When ingested, the poison causes pain, then dizziness, which can turn into fever, and then into convulsions, and end in coma.

Rescue. Fortunately, many pharmaceutical companies already stock the antidote. You just have to get to the nearest hospital as soon as possible and hope that they have time to stock up on this vaccine.

Box jellyfish

A swim in the waters of Asia and Australia may not end the way you would like if a box jellyfish swims nearby. She has so much poison that in a couple of minutes she can poison about 60 people. The burn causes severe pain, simultaneously affecting the nervous system and heart. Depending on the amount of poison injected, death can occur within 4 minutes.

Rescue. Assuming that events do not develop according to the worst-case scenario, you will have 10-20 minutes left. While the timer is counting down the minutes of your life, you need to swim to the shore and run to the rescuers to call an ambulance. Just a couple of years ago, researchers found an antidote for the deadly box jellyfish venom, and if the victim is taken to the hospital on time, he can be saved.

Tree frogs

The price for a fantastic panorama of the rainforests of Central and South America for individual travelers is their own life. Jaguars, okapis, anacondas – there is just no one here! However, the most feared is a small motley poison dart frog. In general, they are peaceful, and attack only small insects and spiders. But if you lean in the wrong place or stand up, in contact with a frog, you will only have a few hours to live. The frog’s skin is covered with glands that secrete this poison. It contains about a hundred different substances and causes a nerve-paralytic effect that leads to death.

Rescue. Vaccines against dart frog venom haven’t been invented yet, so keep your eyes peeled!

Brazilian wandering spider

In order to avoid emergency situations, it is better to escape from the heat in Latin America with an air conditioner, and keep windows and doors closed, especially if thickets of vegetation grow nearby. Otherwise, there is a chance that the Brazilian wandering spider will crawl in search of food and hide somewhere among your clothes or in your shoes. A spider bite causes a severe allergic reaction, which can turn into paralysis of the respiratory muscles and death in a couple of hours.

Rescue. If, nevertheless, you clogged everything that is possible, but did not quite successfully take on a bunch of bananas, and these spiders love to hide everywhere, then urgently go to the nearest hospital, which has been supplied with an antidote from spiders with the most powerful neurotoxic poison since 2004.

Cone

Noticing a colorful shell in the waters of the Indian and Pacific Oceans and the Red Sea, a rare tourist resists the temptation to take it as a souvenir as a keepsake. However, inside this colorful house, its owner is hiding, who, when trying to take it, begins to attack, sticking a modified goiter with poison. Not only is the injection itself very painful, but it can also cause numbness, dizziness and paralysis of the respiratory system, which leads to you know what.

Rescue. The best way to avoid shellfish is to buy souvenirs in specialized stores. If you want to take such a souvenir from the sea, blame yourself, since a protective vaccine against its poison has not yet been invented. Having met with him, the locals immediately incise the bite and bleed, but how this traditional medicine works is unknown. For everything about everything you will have from 3 to 5 hours.

Lonomia

Another inhabitant of the forests of South America can cause kidney failure and prevent blood clotting. Before becoming a beautiful butterfly, the Lonomia caterpillar hides among the forest vegetation, disguising itself as the surrounding foliage and plants. With such camouflage, it is very difficult to notice, and one careless movement leads to contact with the caterpillar’s protective spikes, which carry poison.

Rescue. Brazilian doctors have developed an antidote for caterpillar toxin. Before its introduction, you will have a head start of 24 hours! The whole difficulty is that the burn from the spikes looks like a giant bruise and some simply do not pay attention to it, believing that it will pass by itself. Therefore, you will notice dark spots on the body – immediately run to the hospital.

Blue-ringed octopus

The size of this octopus is 12-20 cm, but it contains enough poison to kill a person. You can come across it in the coastal waters of the Pacific Ocean – from Japan to Australia. The injected venom produces a nerve agent that can be fatal in as little as 1. 5 hours.

Rescue. No antidote for this scourge has yet been invented. After a bite, you need to get ashore as soon as possible, contact the doctors and pray – and what other options – that the effect of the poison will be limited to numbness of the mouth, blurred vision and speech difficulties.

Rockfish

This marine fish lives near coral reefs and disguises itself as a rock. Do you like diving off the coast of Hurghada, Sharm el-Sheikh and Dahab? Well, it increases your chances of encountering an underwater “monster”. Its poisonous toxin provokes severe pain and paralysis. In the worst case scenario, death can occur in 2-3 hours.

Rescue. Poison can be reduced with a hot compress and pain can be relieved with a local anesthetic. But as long as you are able to move and speak, it would be wiser to surrender into the hands of local doctors.

Fugu

Fugu fish contains a lethal dose of tetrodotoxin. Fortunately, it is contained only in the internal organs and skin, and you can risk signing a death sentence for yourself if you decide to go to a specialized restaurant in Japan that serves this same fish.