Is that a spider bite? Probably not

Is that a spider bite? Probably not

Are you afraid of spiders? While the fear is quite common, the chances of actually being bitten and harmed by a spider are smaller than many might think.

Defying a reputation sullied by horror movies and scary listicles, spiders are usually not aggressive, and most bites occur because a spider is trapped, threatened or unintentionally contacted, says the Centers for Disease Control and Prevention (CDC).

And, even those self-defense strikes are much rarer than people realize.

Research has shown that over 80 percent of suspected “spider bites” are actually caused by other arthropods, such as insects and ticks, or reactions to chemicals, allergies or infections. In fact, a recent study showed that more than 30 percent of people with skin lesions who said they had a spider bite actually had methicillin-resistant Staphylococcus aureus (MRSA) infections.

“Generally, you have to work pretty hard or be very unlucky to be bitten by a spider,” says Dr. Rushia Butler, a family medicine physician on staff at Advocate South Suburban Hospital in Hazel Crest, Ill. “Spider bites tend to be the go-to self-diagnosis for many people, which is unfortunate because that misidentification can lead to delay of treatment for the real cause of pain or irritation.”

According to the American Academy of Family Physicians, there are more than 3,000 species of spiders, most of which can’t inflict medially-significant bites to humans.  In the U.S. there are only two types of spiders that are considered venomous enough to be harmful to humans – black widow spiders and brown recluse spiders.

According to the CDC, spider bites account for about seven deaths in the U.S. each year. That’s significantly less than bees, wasps and hornets (about 58 deaths annually) and cows (notably 20 times more lethal than sharks, at 20 deaths per year).

Dr. Butler says that a typical reaction to a spider bite may involve localized reddening and various degrees of swelling, itching and pain. A small red, blue or black discoloration can develop around the bite site. The area may remain tender for a few days, and a small sore can develop that soon begins healing.

For most people with spider bites, says Dr. Butler, including black widow and brown recluse spider bites, the following treatments should be enough to help alleviate symptoms and prevent permanent harm:

  • Clean the bite with mild soap and water. Apply an antibiotic ointment if you think the bite was caused by a brown recluse spider.
  • Apply a cool compress to the bite. This helps reduce pain and swelling.
  • If the bite is on an arm or leg, elevate it.
  • Take over-the-counter medications as needed. Pain relievers such as acetaminophen, ibuprofen or an antihistamine can help minimize symptoms.
  • Watch the bite for signs of infection.

Dr. Butler does, however, recommend following up with your physician if you know you were bitten by a black widow or brown recluse, if pain and swelling don’t get better in a day or two or if a sore just won’t heal.

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  1. This was a very informative article! I do have a question – do cow bites really kill 20 people a year? I grew up downstate in farm country and didn’t know that cows even bite!

    and cows (notably 20 times more lethal than sharks, at 20 deaths per year).

    • Peggy, I think the “death by cow” numbers include all causes, including being crushed to death by one or more of them (think stampedes, being pinned against something by the cow moving, etc); I’d be surprised if there were that many deaths due to cow bites at all (though, they like their salt, so it could be fingers have been lost to cows’ teeth, which led to bleed-out or infection causing death).

About the Author

Nate Llewellyn
Nate Llewellyn

Nate Llewellyn, health enews contributor, is a manager of public affairs at Advocate Medical Group. Nate began his career as a journalist and builds daily on his nearly 20 years of writing experience. He spends most of his free time following his wife to their two sons’ various activities.