Spider Bites

What are spider bites?

Spider bites — especially bites that can harm humans — are rare. All spiders make venom (a poison) that they use to paralyze and kill their prey. But most spiders aren’t aggressive to people, and their fangs are too small to puncture human skin. Spiders usually only bite humans when they feel threatened, like when you trap them or unintentionally make contact with them.

For the most part, spiders perform a vital function by eating insects that can destroy crops.

When to worry about a spider bite

There are at least 60 different spider species in America, but only a few pose any danger to humans. These more dangerous spiders include:

• Black widows: These black spiders have a red, hourglass shape on their bellies. Black widows like to build webs in woodpiles, building overhangs (eaves), fences and outhouses. They mostly live in the Western and Southern U.S.
• Brown recluses: Sometimes called fiddleback or violin spiders, these brown spiders have a dark, violin-shaped mark on their heads. Brown recluses live in Midwestern and Southern states. They like dry, sheltered areas, such as piles of wood, rocks and leaves. Indoors, brown recluses seek out dark closets, attics and shoes.
• Hobo spiders: These brown spiders have a grey V-shaped (herringbone) pattern on their bellies. They build funnel-shaped webs in dark, moist basements, crawl spaces, window wells and woodpiles. Hobo spiders are mostly found in the Pacific Northwest.

Other types of spider bites

There are almost 50,000 different spider species around the world. While most spiders are too small and their venom too weak to cause any danger to humans, they’ll still bite when they feel threatened. In the U.S., nonpoisonous spider bites include:

• Wolf spider bite: Wolf spider bites may tear your skin and cause redness, pain and swelling. But you usually don’t need to seek medical attention. Wolf spiders can be found throughout the U.S. They get their name from the way they stalk their prey like a wolf. Wolf spiders can be brown or gray and reach 3 to 4 inches long. They can be large and hairy and are sometimes mistaken for tarantulas.
• Camel spider bite: Camel spider bites are very rare. While they look and sound scary, camel spiders don’t usually bite. They can run 10 miles per hour and make a screaming sound while running. Camel spiders have long bodies that make them look like scorpions. They’re light brown and can reach lengths of 5 inches. Camel spiders can be found in the deserts of the Southwestern U.S.
• Jumping spider bite: Jumping spider bites are one of the most common house spider bites. Jumping spiders have short, hairy bodies and range in length from one-fifth to three-quarters of an inch. Jumping spiders get their name because they move erratically and jump from one location to another. They live throughout the U.S. and are usually found outside in gardens and vegetation.
• Banana spider bite: Banana spider bites can feel kind of like a bee sting. The bite may produce mild redness and stinging, but it should quickly go away. Female banana spiders have long, yellow-spotted bodies that look like a banana. They can reach about 3 inches long. Male banana spiders are dark brown and not as long. Banana spiders can be found in warm regions from North Carolina to the Gulf states, typically in woodlands and forests.

How common are spider bites?

Experts aren’t sure how many people get spider bites every year. Most of the time, you may not know a spider bit you. Or you may think an insect bit you, instead of a spider.

Bites from black widows or brown recluses are most dangerous to children (because of their small size) and people age 60 and older (who may be weaker or in poor health). In the U.S., fewer than 3 people die every year from a spider bite. Most of these deaths occur in children.

What are the symptoms of a spider bite?

Spider bite symptoms vary depending on the type of spider.

Black widow spider bites cause an immediate, sharp, pinprick-like pain. The bite area then becomes numb. Other signs of a black widow spider bite include:

• Difficulty breathing.
• Droopy or swollen eyes.
• Headache.
• Increased saliva production.
• Nausea and vomiting.
• Painful muscle cramps and stiffness in your stomach, shoulders, chest and back.
• Profuse sweating.
• Itchy skin rash.

Brown recluse spider bites aren’t immediately painful or noticeable. Instead, you might feel pain an hour after the bite. Other signs of a brown recluse spider bite include:

• A blister surrounded by a bruise or reddish skin color (similar to a bull’s-eye). The blister may rupture and form a skin ulcer that later scars.
• Itchy skin in the bite area or all over your body.

Hobo spider bites rarely cause pain. Signs of a hobo spider bite include:

• Severe headache within minutes or hours after the bite. This headache may last for a week.
• Hardened skin in the bite area within 30 minutes of the bite.
• Red, swollen skin.
• Blisters that produce pus.
• Fatigue.
• Nausea.
• Cognitive impairment (memory problems).

What does a spider bite look like?

If you’ve been bitten by a spider, you may see a set of tiny fang marks where the spider broke your skin. You may have a small bump or a blister at the site. In addition, you may notice mild swelling and redness or skin discoloration.

What causes spider bites?

Spiders aren’t typically aggressive toward humans. Bites occur when spiders feel threatened and need to defend themselves.

What are the risk factors for spider bites?

Anyone can accidentally come into contact with a spider and get bitten. Still, some people may be more at risk because their jobs or actions put them in closer contact with places where spiders live. People at risk include:

• Outdoor workers, including landscapers, groundskeepers and farmworkers.
• Children who play in piles of leaves or rocks.
• Hikers.
• Janitors.
• Machine operators.

What are the complications of a spider bite?

Some brown recluse bites cause a skin ulcer (wound). If the wound doesn’t heal, you might need surgery.

Black widow bites are the most serious. Children under 16 and people older than 60 may need hospitalization to treat:

• Breathing problems.
• Heart issues.
• High blood pressure.
• Severe muscle pain and cramping.

How is a spider bite diagnosed?

Seeing the spider is the best way to confirm both a bite and the type of spider. Otherwise, there isn’t a way to test for a spider bite or determine what bit you.

Your healthcare provider may make a diagnosis based on your symptoms. Your provider may also send a sample of fluid from a blister to a lab to check for skin infections that cause similar symptoms, such as methicillin-resistant staphylococcus aureus (MRSA).

How do you treat a spider bite?

Spider bite treatment will vary depending on your symptoms and the type of spider that bit you.

Treatment for black widow spider bites may include:

• Black widow antivenom (antivenin).
• Muscle relaxers.
• Sedatives.
• Pain medicines.

Treatment for brown recluse and hobo spider bites include:

• Daily cleaning with a povidone-iodine solution to prevent infection.
• Soaking the bite area in sterile saltwater (saline) solution three times a day.

What should I do if a spider bites me?

You should never attempt to suck out or remove venom from a spider bite. Instead, follow these steps:

• Clean the bite area with warm water and soap.
• Apply a cold, damp washcloth or an ice pack to the bite area.
• Elevate the bite area.
• Take an antihistamine (allergy medicine) to ease itching and swelling.
• Take an over-the-counter (OTC) pain reliever for pain and swelling.
• Seek immediate medical attention for severe symptoms.

How can I protect myself from spider bites?

To protect yourself and your family from spider bites:

• Apply insect repellant that’s registered with the U.S. Environmental Protection Agency (EPA).
• Keep firewood outside and check it for spiders before bringing it into the house.
• Shake your shoes, hats and gloves to check for spiders before putting them on.
• Treat clothing and shoes with permethrin, an insecticide.
• Wear gloves when carrying wood, working in the garden, moving rocks or in other outdoor settings.
• Wear long sleeves and pants in wooded areas.

What is the prognosis (outlook) for people who have spider bites?

Most people with spider bites experience mild symptoms like pain and swelling. These symptoms gradually go away with at-home care.

You may have more painful and severe symptoms if a black widow, brown recluse or hobo spider bites you. With proper medical care, most people recover from venomous spider bites.

When should I call my healthcare provider?

You should call your provider if you experience:

• Difficulty breathing.
• Heart palpitations, a racing pulse or other heart problems.
• Nausea and vomiting.
• Severe muscle pain, cramps, weakness or paralysis.
• Signs of infection, such as fever or yellow discharge from the bite area.
• Vision problems or severe headache.

What questions should I ask my healthcare provider?

If you have concerns about a spider bite, you may want to ask your healthcare provider:

• What’s the best treatment for my symptoms?
• How can I prevent future spider bites?
• Am I at risk for other problems?
• Should I look out for signs of complications?

A note from Cleveland Clinic

Spiders get a bad rap, but they provide a helpful service by reducing the number of insects on the planet that could destroy crops and land. Spiders really don’t want to bite you. They only bite when they’re trapped or feel the need to defend themselves. Most spider bites are harmless. Your healthcare provider can offer suggestions for alleviating symptoms at home. You should seek immediate medical attention if a black widow, brown recluse or hobo spider bites you, or if you’re noticing symptoms of these bites, as most people who get bitten don’t see the spider.