Brown Recluse Spider Bite: Symptoms, Diagnosis, Treatment

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Brown Recluse Spider Bite

Though many spider bites aren’t serious, a brown recluse spider bite may cause severe side effects or require immediate medical attention. Properly identifying the bite can lead to better management of symptoms to treat different stages of the bite under the care of your healthcare provider.

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Overview

What is a brown recluse spider?

The brown recluse spider is an eight-legged arachnid that is tan to dark brown in color, with a violin marking on its back that can range anywhere from 1/4 inch to 1/2 inch long. Younger spiders or those that have just molted won’t have the violin marking.

Where does a brown recluse spider live?

Brown recluse spiders can be found in the southeastern and midwestern U.S. The brown recluse spider prefers to live in warm, dry and dark places.

Outdoors, brown recluse spiders can be found near rocks, utility boxes, near woodpiles and under bark.

Indoors, brown recluse spiders could live in any area that has not been disturbed. They can be found in boxes, in unworn clothing and shoes, in corners of a home and in crevices such as in an attic, crawl space, basement or closet.

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Who do brown recluse bites affect?

The brown recluse spider is not aggressive but will bite anyone if it feels threatened. Children, the elderly and those with preexisting medical conditions are most likely to have a severe reaction to the bite.

How common is a brown recluse spider bite?

Almost all spiders have the ability to bite, but the fangs of most spiders are too small to penetrate human skin. Spider bites, including bites by the brown recluse, cause only a few deaths per year in the U.S., usually in children.

How does a brown recluse bite affect my body?

Brown recluse bites can cause redness, itchiness, pain and wounds. If the wound is untreated, it could lead to bruising, a blister, an open sore and scarring.

Symptoms and Causes

What would cause a brown recluse spider to bite?

A brown recluse could bite you if you disturb its home. Though the spider will not pursue a person, if you come in close contact with a brown recluse, it may bite to defend itself. Spiders like to hide in dark spots like beds and clothing. Spider bites tend to occur indoors when you unknowingly come into contact with it.

What happens when a brown recluse bites you?

A bite from a brown recluse spider will not be instantly noticed because its bite is painless. Bite reactions vary from mild irritation to a potentially dangerous reaction.

What are the symptoms of a brown recluse bite?

• Pain.
• Ache at the site.
• Pain surrounding muscles near the bite.
• Pain in your abdomen, back, chest and legs.
• Blister at the site.
• Swelling.
• Bruising.

What are severe symptoms of a brown recluse bite?

• Rash.
• Fever.
• Dizziness.
• Vomiting.
• Chills.
• Restlessness or difficulty sleeping.

If you experience any severe symptoms, seek medical attention immediately.

What are the stages of a brown recluse spider bite?

Hours after a bite

• The area of the bite becomes sensitive and red about three to eight hours after the bite.
• The bite site feels like it is burning.
• The bite site changes color. It can have a bullseye look or can bruise and have a blueish color.

Three to 5 days after a bite

• If the spider injected a small amount of venom, immediate discomfort should disappear.
• If the venom spread beyond the bite area, discomfort could continue for several days and an ulcer would appear on the bite site.

Seven to 14 days after a bite

• In severe cases, the skin around the ulcer breaks down and becomes a wound that could take several months to heal completely.

Three weeks after a bite

• The majority of bites will heal after three weeks.
• A thick, black scab will cover the wound.

Diagnosis and Tests

How is a brown recluse bite diagnosed?

It can be difficult to identify a brown recluse bite unless you saw the spider bite you, especially since the brown recluse’s bite cannot be felt until hours after the bite occurred.

If you suspect you have been bitten, call a healthcare professional or visit the emergency room and bring the spider for identification purposes, if possible.

Can my doctor test for a brown recluse spider bite?

There is no test available to identify a brown recluse spider bite. But your healthcare provider may test for skin infections or other conditions based on the wound or blister as a result of the bite.

Management and Treatment

What are the effects of a brown recluse bite?

Brown recluse spider bites can cause wounds. If the wound is left untreated, the wound could result in an infection or scarring.

How do I manage symptoms of a brown recluse spider bite?

• Immediately clean the bite area with soap and water.
• Apply a damp cloth with cold water or ice to the bite area to reduce swelling.
• Elevate the bite area, if possible.
• Seek medical attention for severe symptoms.
• A healthcare provider may prescribe antibiotics to prevent infection.

How soon after treatment for a brown recluse bite will I feel better?

The majority of brown recluse bites will heal after three weeks if the bite is not severe. Seeking treatment at the first sign of a brown recluse bite will ease recovery time.

What happens if a brown recluse bite goes untreated?

If the area around the bite continues to grow and your pain increases, the wound may be infected, especially if the wound begins to drain a cloudy liquid. Infections could be dangerous and spread further from the wound. In serious cases, an untreated and infected wound could be life-threatening.

Prevention

How can I reduce my risk of being bitten by a brown recluse?

Awareness and understanding where brown recluse spiders live are the first steps in reducing your risk of a bite. However, brown recluse spiders frequently go unnoticed due to their habitat and sneaky nature.

How can I prevent brown recluse spider bites?

There are steps you can take to prevent bites from a brown recluse spider. These include:

• Stop spiders from entering your home by sealing small openings with caulk.
• Remove spider webs from homes.
• Keep firewood at least 20 feet away from your home.
• Wear gloves when moving wood.
• Wear long sleeves and pants in areas with spiders.
• Shake clothing and shoes before wearing.
• Contact a pest control professional if you notice your home has a brown recluse spider infestation.

Outlook / Prognosis

What can I expect if I am bitten by a brown recluse spider?

If you are bitten, you can expect the following:

What it feels like

There may be delayed pain after the bite occurs.

What it looks like

• A blister.
• Swelling at the site.
• An ulcer (wound).

With proper care, most people will recover from a brown recluse spider bite.

Living With

When should I call the doctor about a brown recluse bite?

Call your doctor or visit the emergency room immediately if you experience any of the following:

• Fever.
• Dizziness.
• Chills.
• Nausea.
• Your wound looks like it’s infected. It may be red, swollen, drain cloudy fluid or be painful to the touch.

What questions should I ask my doctor about a brown recluse spider bite?

• How do I treat my symptoms?
• What are the signs of infection?
• Am I at risk for any complications?

A note from Cleveland Clinic

Unfortunately, a bite from a brown recluse spider will not turn you into a comic book superhero. Discomfort from a bite is temporary and can be alleviated with quick treatment and proper wound care hygiene. If you live in an area with brown recluse spiders, take precautions in garages, basements and closets, and reach out to a pest control specialist if you feel that there is an infestation.

Last reviewed by a Cleveland Clinic medical professional on 05/06/2022.

References

• American Academy of Pediatrics (AAP). Spider Bites. (https://www.healthychildren.org/English/health-issues/conditions/from-insects-animals/Pages/Spider-Bites.aspx) Accessed 5/6/2022.
• American Osteopathic College of Dermatology. Spider Bites. (https://www.aocd.org/page/SpiderBites) Accessed 5/6/2022.
• Merck Manual. Spider Bites. (https://www.merckmanuals.com/home/injuries-and-poisoning/bites-and-stings/spider-bites?query=recluse) Accessed 5/6/2022.
• National Pest Management Association. Brown Recluse Spiders. (https://www.pestworld.org/pest-guide/spiders/brown-recluse-spiders/) Accessed 5/6/2022.
• All About Pests. The Bite Stages of a Brown Recluse Spider. (https://pestguide.org/pest-guide/the-bite-stages-of-a-brown-recluse-spider-an-infographic) Accessed 5/6/2022.

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Brown Recluse Spider Bite: Symptoms, Diagnosis, Treatment

A bite from a brown recluse spider can be mild or severe and may require medical attention. The toxins from this spider’s bite can cause tissue death.

Bites from the brown recluse spider almost never result in death but can cause serious skin damage, nausea, and muscle pain. With proper care, mild bites resolve within days to weeks, while more severe cases can take months to heal.

A bite from the brown recluse spider requires first aid, and if necessary, professional medical attention. Treatment often includes cleaning the affected skin, pain relievers, and icing.

Keep reading to learn the symptoms and stages of a brown recluse spider bite, how to identify the spider, and when to seek help.

What’s in the bite?

Even though this spider’s size maxes out at about a half-inch, its venom is more toxic than that of a rattlesnake. Luckily, the brown recluse is only capable of releasing a little into our system.

Here are two key toxins in the venom:

• Sphingomyelinase D has the potential to destroy skin tissues.
• Hyaluronidase can speed the venom’s penetration into tissue.

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A brown recluse’s venom can destroy blood vessels, tissue, and nerves. As a result, the skin tissue can die, a phenomenon called skin necrosis.

In a 2020 study of 97 patients bitten by the spider, 40 percent experienced hemolysis, the damaging or breaking down of red blood cells.

Prompt treatment can slow these effects and allow your skin to begin healing faster.

Initial bite

Brown recluses have very small fangs, and their bite is usually painless. Unless you saw it happen, at first, you might not even be aware that a spider has bitten you.

You may start to notice a red, tender, and inflamed area about 2 to 8 hours after the spider bit you. Over the course of the next several hours, the irritation may cause a burning sensation.

The bite may appear as two tiny puncture holes . Early on, its center will be a pale color, with an inflamed reddish outer ring. The pain usually reaches its height at about the 24-hour mark after you are bitten.

After 3 to 5 days

In some people, the brown recluse’s venom is localized to only the area where the spider bit you. If the spider injected minimal venom and you’re healthy, the discomfort usually goes away in a few days.

But for others, the venom spreads. This causes the wound to expand, usually over a period of several days to weeks. Some people will develop a blister, and then a “necrotic lesion” due to the spider’s bite. This means the bite causes an ulcer or open sore, and tissue begins to die.

This may look like the following:

• dry, sinking patch of skin
• bluish-appearing patch of skin
• redness around the lesion with a pale center
• central blister

After 1 to 2 weeks

For mild bites, you should be mostly healed by 3 weeks or see a drastic reduction in inflammation.

But if you have a more severe bite, the spider’s toxin will continue to break down the skin, especially if untreated. The site of the wound may start to develop necrotic (dead) tissue called eschar. This looks like a big, black scab covering the wound area.

3 months later

Most brown recluse bites will heal fully, without complications, in 3 months or less.

In very rare cases where a lot of venom was delivered, necrosis in the wound can extend beyond the skin and into the muscles. If tissue death continues to occur or has already affected a large area, you’ll need to be evaluated by a surgeon. Surgery may be required to remove or repair excess dead tissue.

If the wound hasn’t responded to treatment or symptoms don’t align with the typical presentation of a brown recluse bite, it may be time for a differential diagnosis. Your doctor will consider other potential culprits of your symptoms, like another type of insect bite or a separate skin condition.

Severe reactions to a brown recluse spider bite

Some people have severe or life threatening reactions to brown recluse bites. These responses to the bite are more likely in those with compromised immune systems, including children and older adults.

Severe reactions to a brown recluse bite can include the following symptoms:

If you or a loved one is experiencing the above symptoms, seek emergency medical assistance. This may be a sign of anaphylactic shock, a life threatening allergic reaction.