What Are Spider Bites?
Spiders live all over the United States. You might notice their webs out in nature, your backyard, or inside your house. They might not look pretty, but they’re very helpful. They eat other creepy-crawlies, which means fewer bugs for you! Most of the time, spiders mind their own business. Spider bites are fairly uncommon.
If a spider does bite you, it usually isn’t a problem. That’s because most spiders’ fangs are too short to break your skin, and their venom isn’t strong enough to endanger a creature as large as a human.
Who is at risk?
You’re more likely to be bitten by a spider if you’re a:
- Landscaper, farmworker, or other outdoor worker
- Hiker
- Child who plays in leaf piles
- Janitor
- Machine operator
Some people are at higher risk of life-threatening reactions to a spider bite. These people include:
- Children
- People over 60
- People with high blood pressure, heart disease, or other serious medical conditions
If people in these groups get bitten by a black widow or brown recluse spider, they should get emergency medical help right away.
Poisonous spider bites
The CDC says only two venomous spiders that are native to the United States can do real harm when they bite a person: black widows and brown recluses.
Black widow spiders (Latrodectus mactans, L. variolus, L. hesperus) live throughout the United States but are most common in the South and West. They tend to live in woodpiles, in stumps or rodent burrows, under rocks, along fences, in sheds or outhouses, and in areas with a lot of debris in the South and West. They also nest in basements or crawl spaces. These spiders are less than a half-inch long, and are black with a red hourglass-shaped mark on their belly. Only female black widows have neurotoxic venom. This venom causes pain at the site of the bite, then throughout the chest, belly, or body.
Brown recluse spiders (Loxosceles reclusa) live in the Midwest and South. They prefer dark, dry areas like garages, attics, shoes, and piles of rocks or firewood in the Midwest or South. They often end up in clothing and bedding. They’re golden brown with a dark violin-shaped mark on the head, and are ¼- to ¾-inch long. Unlike most spiders, a brown recluse has six eyes. If you get bitten, you might notice a sting, then a small white blister. Brown recluse venom can severely damage skin, causing a necrotic wound (a wound in which tissue dies).
One spider that you probably shouldn’t worry about: the hobo spider (Eratigena agrestis, formerly Tegenaria agrestis). Hobo spiders are native to Europe but also live in the Western United States. They’re brown, about a half-inch long, and are fast runners. But they’re easy to mix up with similar types of spiders.
For years, people mistakenly believed that hobo spiders caused dangerous wounds. But in reality, there was never solid evidence behind those claims. In 2011, a study concluded that hobo spider bites probably aren’t dangerous. They might cause some redness, mild pain, and temporary twitching, but that’s it. But more research is needed to be sure.
All of these spiders tend to keep to themselves. They don’t bite unless they’re cornered. People sometimes invade their spaces without knowing it. That’s when they get bitten.
Spider Bite Symptoms
Most spider bites cause only mild symptoms. Like other bug bites, they might lead to redness, pain, swelling, or sometimes itchiness. Other times, they’re painless. Some have one or two bite marks.
They also can look a lot like wounds caused by other things, like bacterial infections. Because of this, spiders are often blamed for sores they didn’t cause. It’s hard to know whether your wound was caused by a spider bite, unless you saw the spider bite you.
In rare cases, black widow and brown recluse spider bites can cause dangerous problems. But even their bites usually aren’t serious. You also don’t need to worry about bites from hobo, wolf, camel, jumping, or banana spiders.
Symptoms of a black widow spider bite
Most black widow spider bites aren’t serious. But in rare cases, especially among children, they can have serious consequences.
In addition to the general symptoms listed above, a black widow spider bite can cause:
- Pain that spreads to the back, belly or chest
- Swelling in your hands and feet (but usually not around the bite)
- Severe stomach cramps or stiffness
- Nausea or vomiting
- Tremors
- Trouble breathing
- Sweating
- High blood pressure
- Fever
- Droopy, swollen eyes
- Drooling
You’ll start to feel better after 48 hours, with the most severe symptoms gone within a few days. Mild symptoms may last weeks.
If you have a heart condition or other serious medical problem, or a child is bitten, get help right away.
Symptoms of a brown recluse spider bite
Most brown recluse bites are relatively harmless. You might not notice symptoms at all. But in rare cases, especially among children, they can have dangerous complications.
A brown recluse bite goes through several stages:
- The bite: In most cases, the bite itself is painless.
- Within an hour: The bite area will redden. If you look closely, you might see two fang marks.
- In 2-8 hours: The center of the bite will become pale, while the red area expands around it. This forms a “bull's-eye.” Some people get:
- Bruising
- Muscle pain
- Nausea
- Headaches
- Fatigue
- Fevers
- Chills
- Body aches
- The next few days: A white blister will form, followed by a 2-inch-wide, hard, scabby bump. The bite will turn dark blue, purple, or black. The middle part will sink, forming a crater. At this point, mild bites will start to get better.
- The next few weeks: Over time, the dead skin will peel away.
Brown recluse spiders have a bad reputation for causing large, festering wounds. But this is an exaggeration. Although their venom can cause severe skin damage, they are often unfairly blamed for wounds caused by bacterial infections and other conditions.
In reality, about 10% of brown recluse spider bites cause severe skin damage. If the bite looks like it’s getting worse, call your doctor. You might need a skin graft to treat the wound. This is when a doctor takes healthy skin from another part of your body and uses it to cover the damaged skin. These wounds can take months to get better and might leave scars.
Children are more likely to have a severe, body-wide reaction to a brown recluse bite. This might look like fever, joint pain, and seizures. In rare cases, this could lead to organ failure or death.
If you have severe body-wide symptoms, or a small child was bitten, call 911 right away.
Symptoms of a hobo spider bite
Contrary to popular belief, hobo spider bites probably aren’t dangerous. Their venom doesn’t damage cells, and they don’t seem to carry harmful bacteria.
Some people have reported getting necrotic wounds. But there’s no proof that most of those people were bitten by hobo spiders, so scientists believe the wounds were caused by other conditions.
Only two people have had proven hobo spider bites. One person developed a necrotic wound, but she had a medical condition that could have also caused the wound. The other person had pain, redness, and twitching at the site of the bite. His symptoms got better in 12 hours. More research is needed to learn about hobo spider bite symptoms.
Is a wolf spider bite poisonous?
Wolf spiders live throughout the United States. They’re big, brown or gray, and hairy. They can grow up to 3-4 inches long, so some people mistake them for tarantulas.
In the past, people thought that wolf spider bites caused large, festering wounds. But more recent evidence has shown that isn’t the case. They aren’t poisonous, either. If you’re bitten by a wolf spider, you might have some redness, pain, and swelling, but that’s it.
Spider Bite Diagnosis
Spider bites look a lot like other bug bites and infections. To identify the cause of your sore, your doctor will ask about your symptoms and how you were bitten. They’ll want to know if you saw a spider bite you, and if you did, what the spider looked like. (It might help to bring a photo of the spider that bit you.) That’s really the only way they can know for sure that it’s a spider bite.
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 an infection or vasculitis (a condition that causes blood vessels to swell). They may take a sample of fluid from your sore to test for infections like methicillin-resistant staphylococcus aureus (MRSA).
Spider Bite Home Remedies
Many people who are bitten by spiders don’t need to visit the doctor, even if they’ve been bitten by a black widow or brown recluse. If you have only mild symptoms, you may be able to care for your spider bite at home.
There are some easy tips for spider bite self-care. Here’s what to do:
- Stay calm. If possible, take a picture of the spider. Identifying the spider will help your doctor know how to treat you.
- Don’t try to suck out or remove the venom.
- Clean the wound with soap and warm water.
- Dab it with antibiotic cream three times a day.
- Cover it with a sterile (clean) bandage.
- Raise the area that was bitten. This will help prevent swelling.
- Put an ice pack or cold, damp cloth on the bite. Do this 15 minutes each hour. It will help slow down the absorption of the venom and prevent swelling.
- If it hurts, take over-the-counter pain medicine.
- If it’s itchy, take an antihistamine like diphenhydramine (Benadryl) or cetirizine (Zyrtec).
- Watch for more severe symptoms. Call a doctor if needed.
If you’ve been bitten by a brown recluse, clean the area once a day with povidone-iodine solution. This helps prevent infection. You also can soak the area with salt water three times a day.
Spider Bite Treatment
See a doctor right away if you were bitten by a black widow and have extreme pain or other serious symptoms. They may need to give you antivenom through an IV. This takes about 30 minutes to work. But it can also cause allergic reactions in some people.
Besides black widow antivenom, there aren’t any spider bite medications. But there are medicines that can help with the symptoms. Depending on how you feel, your doctor might prescribe:
- Muscle relaxants
- Sedatives
- Pain medication
If the bite gets infected, you may need antibiotics.
You might also need to get a tetanus booster. That’s because tetanus spores sometimes collect inside spider bites.
When to worry about a spider bite
Most times, spider bites are mild and get better on their own. This is true even for black widow and brown recluse bites. But sometimes, they can cause more serious reactions. Dangerous reactions are more common among children, people older than 60, and people who have medical conditions.
Call your doctor right away if:
- You have a headache, cramping, chills, a fever, body aches, nausea or vomiting, or other body-wide symptoms.
- The red area is getting bigger.
- The bite area is leaking yellow fluid.
- Red streaks point to the wound.
- The bite area turns into a bull's-eye rash or open wound.
- It’s been 24 hours and the pain is still getting worse.
Get emergency help if you have:
- Severe pain, a fever, stomach cramps, nausea or vomiting, vision problems, weakness, paralysis, or other body-wide symptoms
- Trouble breathing or swallowing
- Heart palpitations or a racing heartbeat
- Tightness in your chest
- A swollen mouth or face
If you think a child was bitten by a black widow or brown recluse, go to the emergency room right away.
How to Prevent Spider Bites
If you are in an outdoor area with firewood, lumber, dark spaces, or debris:
- Wear long-sleeved shirts, hats, boots, 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.
- Clean up clutter and debris.
- Cut tall grass.
- Move piles of firewood and stones away from your home. Before you bring firewood inside, check it for spiders.
- Think about using bug spray that contains DEET. Make sure it’s registered with the U.S. Environmental Protection Agency.
In late summer and early fall, many spiders move indoors. To prevent indoor spider bites:
- Be especially careful in cool, dark spaces, like under the bed, behind bookshelves, and in basements and attics. When you go into these areas, wear long-sleeved shirts, pants, hats, boots, and gloves.
- When stacking storage items, lessen the amount of empty space.
- Make sure that all windows and doors have screens, which can help keep the bugs out
- Seal cracks in the walls and other places bugs can enter your house.
- Shake out shoes, towels, blankets, and clothing before use. Spiders like to hide in things left on the floor.
- Move your bed 8 inches away from any walls. Don’t let bed skirts or blankets hang onto the floor. Spiders can use these to climb into your bed.
- Clean up spiderwebs in your house.
- Think about using a safe indoor bug spray that contains permethrin. Check to make sure it’s registered with the U.S. Environmental Protection Agency.
If you see a spider on you, gently flick it away. Don’t crush it against your skin. This could trap the spider and cause it to bite.
Also, stay up to date with your tetanus shot. (You should get a booster every 10 years.) Some spider bites can become infected with tetanus.
Takeaways
Most spider bites are nothing to worry about. They might get red, swollen, and a little itchy or painful. But in rare cases, a bite from a black widow or brown recluse can be more serious. Get emergency medical help if a child was bitten by a black widow or brown recluse or if you have severe body-wide symptoms like trouble breathing, stomach cramps, and tightness in your chest.
Spider Bite FAQs
- What does a spider bite look like? A spider bite looks a lot like other bug bites, as well as some bacterial infections. It usually causes redness, swelling, and pain or itchiness. You might be able to see one or two fang marks.
- What are the stages of a spider bite? A brown recluse spider bite has several phases. It starts off as red and painful or itchy. In a few hours, it forms a bull's-eye rash. Later, it turns into a white blister, then a dark blue, purple, or black sore with a sunken center.
- Do spider bites look like pimples? Like other common sores, a spider bite can cause redness, swelling, and pain or itchiness. Sometimes they have one or two fang marks.
- What is the advice for spider bites? Most mild spider bites can be treated at home. Clean the wound with soap and water, dab on some antibiotic ointment, apply a bandage, raise the area, and put some ice on it. Call a doctor right away if you start having body-wide symptoms like a fever or a headache. Go to the emergency room if you have severe body-wide symptoms like stomach cramping and trouble breathing, or if a child was bitten by a black widow or brown recluse spider.
