How to avoid, identify, and treat spider bites
Dr. Grant Lipman
Grant S. Lipman, MD, is a clinical assistant professor of surgery in the division of emergency medicine at Stanford University and associate director of the wilderness medicine fellowship at Stanford University School of Medicine.
Tales of spiders have been spun for thousands of years. Greek mythology tells of a jealous goddess, Athena, who transformed the mortal weaver Arachne, into a spider for challenging her. This story teaches the value of hubris and reveals the origins of the word, arachnid, which includes spiders, mites, ticks, and scorpions.
Where spiders are found
Spiders can be found in all kinds of habitats across the United States. From the east coast to the west coast, in southern swamps and southwestern deserts, they can live in both dry and humid climates.
Most spiders like warm, dry areas such as in piles of wood, rocks, or dusty undisturbed corners.
Tip: You can prevent spider bites by avoiding blindly reaching under rocks, logs, or outdoor areas where you may surprise them.
While there are thousands of species of spiders (20,000 alone in North America), only a few spiders are considered venomous or harmful to humans. In the US, there are only two: the black widow and the brown recluse. All other spiders in the US, regardless of how gnarly or terrifying they look, are harmless to humans.
Did you know?
Fewer than 50 spider species have fangs that can even break human skin. And of those spiders with fangs, there’s usually very little toxicity in their bites.
Leave them alone
Spiders are naturally shy and timid and prefer to hide in dark places like inside a tent, storage spaces like attics or sheds, sometimes even in bathroom sinks and bedroom corners. Spiders typically only bite when provoked, so if you encounter a spider outdoors, avoid poking or crushing it. You never know how they might respond. Simply walk away from it.
If you find one in your personal space, here’s what you can do:
- Gently put a bowl or cup over it.
- Slide a piece of paper or cardboard under the container, trapping the spider inside.
- Go far away and release the spider.
(Don’t worry, black widow spiders don’t jump.)
What to do with a spider bite
Spider bites don’t often hurt, so you might not even notice when you’ve got bitten, which can make it difficult to know what exactly bit you. So being aware of and monitoring your symptoms can help you figure out if it’s a worrisome venomous bite, or a harmless bug bite.
Image of a Black Widow Spider
Black Widow Spider
How to identify a black widow spider
- Round, black or dark brown glossy abdomen or body
- Red or orange colored hourglass symbol imprinted on the body
- Legs are longer than their body
- Typically 1-2 inches in size
Black widow spider bite symptoms
Most spider bite injuries are caused by the black widow spider group (latrodectus) – around 2500 cases are reported annually. And it’s important to note, only female black widow spiders are dangerous.
Black widow spider bites feel like a pinprick, but the bites themselves are not the cause for the pain. When the black widow bites, it injects venom that changes the flow of our neurotransmitters (chemical messages) between the nerves and muscles. This disruption can cause severe pain from muscle cramps in our arms, legs, back, and stomach.
Black widow venom can also mess with the body’s nervous system and blood pressure, and cause headaches, nausea, and vomiting.
But can a black widow kill you?
Very rarely. We haven’t seen reported deaths from a black widow in over 40 years.
Black widow spider bite treatment
If you think you’ve been bitten by a black widow spider, you’ll need to get to a medical facility as quickly as possible. Unfortunately, the severe pain from a black widow bite is difficult to control, so most over-the-counter pain medicines won’t help.
The best treatment for the pain from a black widow bite is antivenom. Black widow antivenom has been shown to shorten the duration of symptoms. It works for both children and adults and would need to be given in a hospital setting to monitor for any possible allergic reactions.
Brown Recluse Spider
These brown recluse spiders have the iconic dark brown marking on their back, resembling a fiddle, giving them the nickname “fiddleback” spiders. Notice the objects around them to get a sense of how small they can be.
How to identify a brown recluse spider
- Found in the midwest and the south
- Tan to dark brown in color
- Sometimes called a “fiddleback” spider because the mark near its head looks like a fiddle or violin
- Legs are longer than their body.
- Typically 0.25-1.5 inches in size.
Brown recluse spider bite symptoms
Unlike black widow spider bites, there is no antivenom for brown recluse spider bites.
The bite of a brown recluse spider is usually painless and you may not even know you’ve been bitten until the skin becomes red, itchy, or painful. In some cases, a blister may form that can eventually lead to skin breaking down with an open sore and become dead skin (necrosis) in weeks following the bite. This can take months to fully heal. There is no special medication that can be given to prevent the possibility of eventual skin injury after a brown recluse bite.
Brown recluse spider bite treatment
Most spider bites or insect stings that are itchy or painful can be treated the same.
🧊 Ice it
Put something cold on the skin for 15-20 minutes. A soda can, bag of peas, or even submerging in cold water can all work. If you’re using an ice pack, be sure to protect your skin with a towel or washcloth to prevent frostbite. The cold helps decrease swelling and inflammation and targets the source of the pain in the nerve fibers.
💊 OTC pain medication
Over-the-counter pain medicine like acetaminophen or ibuprofen can also help with the pain. And if the spider bite is very itchy, taking an over the counter antihistamine or allergy medicine can ease your symptoms.
Sometimes a break in our skin barrier from a spider bite or sting can lead to a bacterial infection (otherwise known as cellulitis).
Tarantula spider
Tarantula
Ever encounter a hair-raising tarantula? While they can look terrifying, they are in fact, less harmful than the above venomous spiders. The hair itself on a tarantula can cause the most irritation and itchiness.
How to identify a tarantula
- Found in the southwest and southern states
- Brown to black coloring
- Hairy, densely covered bristles
- Bodies can measure 2-5 inches, but can be up to one foot wide with the legs
Tarantula treatment
If you do come into contact with a tarantula, their bites can be painful, but the reaction typically doesn’t spread. Treat the bite similar to what you would do for other insect bites or stings (see above, or see GOES).
It’s important to remember that we humans are animals too, coexisting with our other animal neighbors. Especially whenever we step outside, we’re now entering their homes and encounters with wildlife are inevitable. Whether the creature has four legs, six legs, eight legs, or no legs – trust that GOES can help you prevent unwanted bites and stings, and manage them when they happen.
