Mar 24, 2015 — Most household spiders don't pose much of a threat to humans, but some bigger and badder spiders have pretty poisonous fangs. Dr. Tom Miller and dermatologist Dr. Mark Eliason discuss how to treat common spider bites and what to do if you get bit by one that's more dangerous. Listen to find out how to react to bites from black widows, hobo spiders, brown recluse spiders and those big hairy spiders in your basement.


Dr. Miller: You've been bitten by a spider. What should you do next? We're going to talk about that next on Scope Radio. I'm Dr. Tom Miller.

Announcer: Medical news and research from University of Utah physicians and specialists you can use for happier and healthier life. You are listening to The Scope.

Dr. Miller: I'm here today with Dr. Mark Eliason. He is an assistant professor of dermatology. Some people are very terrified that a bite might actually be due to a spider such as a brown recluse or a black widow. How often does that occur and if you have been bitten by one of those types of spiders, should you seek medical attention?

Dr. Eliason: Great question. Most of the time, spider bites, specifically, are . . . well, first, I should say that they are actually very rare. We do see spider bites that happen, but when they do, you can often see a change. You can actually see the little fang marks on the skin, although that's hard for most people to see. They're very small.

Dr. Miller: Not like a rattlesnake bite?

Dr. Eliason: No, definitely not. They're smaller than that. But they're usually extremely painful right at the site where the bite occurred, and then they’re less so farther away. Most bites that happen from the dangerous spiders like the black widow or the brown recluse or the hobo spider, which sometimes happens here in Utah as well, those can be associated with what we call necrosis, which is skin that starts to die locally. The skin turns a dark purple color. It starts to die a little bit. And usually the problem with these is that people get secondary bacterial infections. It's not so much that the spiders' bite that hurts them. It's the lack of wound care that then leads to further problems.

Dr. Miller: So if you see a spider, and you are bitten by one, you should probably seek some medical attention, or not?

Dr. Eliason: Well, by and large, the spiders, the most prevalent ones that are in this area, particularly the ones that live in homes are very seldom the dangerous ones. Hobo spiders do like to live in certain types of homes. I don't want to make everyone paranoid about that. But they don't like people. They run away from us. They avoid us. They don't sneak out at night and bite.

Dr. Miller: Most spiders do.

Dr. Eliason: Yeah. So with few exceptions, most spider bites could be managed just by washing the area with a topical antibiotic like the bacitracin or polysporin you can get from the store, and then if the area that was bit, that dark red or darkened area doesn't expand, people don't get a fever. Usually, you can just watch those.

Dr. Miller: Perfect, thank you very much, Mark.

Announcer:, a University of Utah Health Sciences Radio. If you like what you heard, be sure to get our latest content by following us on Facebook. Just click on the Facebook icon at

For Patients

Sign Up For Weekly Health Updates

Get weekly emails of the latest health information from The Scope

Subscribe on Itunes Download Podcast