Spider Bite or Just a Scratch?

Cynthia Dermody
spider bite or scratch?

Dangerous brown recluse spider

My daughter comes home with so many scratches, bruises, and bites that I'm often unfazed when my concerned husband points out a new boo-boo. She's rough and tumble and just being a toddler, so I shrug it off. 

But I should probably take more of an interest, because a mom in the medical questions group was concerned that her son might have been bitten by a brown recluse spider. Yikes! I looked it up and found spider bites are a lot more common than I thought. The brown recluse is just one of several poisonous spiders in the U.S., the other one being the infamous black widow.

Turns out it was a false alarm; the mom's son had an infected cut and was treated for it. But the whole thing got me thinking that I need to pay better attention to my daughters boo-boos, especially when she wakes up in the morning with a strange mark.

I asked Dr. Eric Lavonas, MD, associate director of the Rocky Mountain Poison & Drug Center, how to tell a spider bite from a regular old mosquito bite or cut. Here's what he said about this and other questions:

Spider bites start out as red, raised, warm, itchy or painful areas, but within a day or two the skin in the center breaks down ("ulcerates"), leaving an open area in the middle of the red spot.

How common are they?

Over the last two years, ER's saw a tremendous increase in people seeking care for "spider bites." The problem is, very few of these people actually had spider bites. Rather, skin and muscle infections from a new strain of Staph. aureus have become incredibly common.The patients develop a red, raised, painful area and assume, incorrectly, that they were bitten by a spider while they were sleeping. Not so. Staph infections tend to form pus pockets ("abscesses") beneath the skin; eventually, these will drain foul-smelling liquid.

Could any one of us, regardless of where we live, have a poisonous spider in our homes right now?

Yes. The vast majority of household spiders have tiny mouth parts that can't bite through human skin.Thus, although they do have venom, they're still harmless to humans. But the dangerous spiders in the U.S. fall into two different categories, one of which is spiders whose venom digests skin and muscle ("dermatonecrotic spiders").

Although the brown recluse spider gets all the infamy, there at least six families of spiders native to the United States are able to do this. At least one of these spiders can be found anywhere in the US.

The other is the black widow. These beautiful spiders can be found almost anywhere in the US, though not as commonly in Canada. Their bites are painless at first, and cause nothing more than a minor rash. However, within 30 minutes to a few hours, the victim develops severe muscle pain throughout the body - usually worst in the back and abdomen. These can be excruciating, and almost anyone will seek care in an emergency department.

Brown recluse spiders only live in the Southern US, and rarely in people's homes, but other dermatonecrotic spiders are everywhere.

What does a spider bite look like?

A spider usually leaves a series of bites in a row as it moves along your body. A single puncture mark is not a spider bite.

Should we be afraid of spiders crawling all over our children when they sleep? 

Spiders really don't want to be anywhere near something that weighs 100,000 times more than they do!  Recluse spiders stay away from occupied homes. A house spider might crawl on you while it's exploring the house at night, and bite when you roll over and threaten or crush it. We humans are not spider food. To reduce the risk of this happening, vacuum frequently.

What should we do if we suspect our child was bitten by a spider? 

Minor spider bites can be managed at home: Gently wash the wound twice a day with soap and water, apply Vaseline, antibiotic ointment, or Aloe, and keep covered with a band-aid. Make sure to eat healthy foods and drink plenty of fluids. See your doctor if the open area is larger than a quarter, if the wound is on your face, if the redness extends more than an inch or so from the edge of the open area, if the area gets larger very quickly, or if you develop a fever. 

Unfortunately, even for severe spider bites, nothing works very well to speed healing or reduce scarring. In most cases, gold-standard care consists of managing the wound gently, watching for signs of infection, practicing healthy habits, and waiting for natural healing to take place. Depending on the severity of the bite and the overall health of the victim, healing can take anywhere from a week to several months.

 Any other advice? 

The American College of Emergency Physicians has an excellent emergency guide for spider bites. Parents who aren't sure what to do can always call their poison control center for advice. That number (nationwide) is 1-800-222-1222.  Family physicians and pediatricians are also a great resource.


Did you ever suspect your child was bitten by a spider in the night? What happened?

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