You were not bitten by a brown recluse




"Spider bite" seems to be one of those catch all diagnosis that is meant to be more reassuring than "Dunno".

I had a friend who got a nasty infection after a concert a couple of months ago. They diagnosed it as a spider bite despite not being able to find puncture wounds, then later realized it was MRSA and said "it must have been on the spider's fangs."


Help me. One of those things that really shakes your faith in medicine.

My girlfriend got a super nasty infection on her leg a while back. We were starting a long camping trip, there was the immediate assumption of a spider bite (we had, it is true, spent one night in a very old, infrequently occupied house). It swelled from an angry pimple to about the size of a golf ball, extremely painful the whole time, and so we eventually bailed on the trip and went to back to the closest civilization for urgent care. That doctor, to their credit, didn't diagnose a "spider bite", but also didn't suggest MRSA. Gave her antibiotics and painkillers, suggested the antibiotics were likely not going to have much impact at that point, and a few days later it "popped" (ugh) and started healing. She's still got a mark from it, over three months later.


Damn dirty spiders! Seriously though, now I'm going to have to Google spider bites.


"it must have been on the spider's fangs."

Brown recluses are crafty like that.


Now, all that said:

  1. They're not that common.

I don't know where the hell you're from, but many of the places I've been are thick with them. Arkansas is overrun, and I say that as someone whose parents are amateur entomologists. I've also come across many in Northern California, even in my office on the UC Berkeley campus. I found a pair of gigantic ones in a cabin on the Russian River (they were nearly the size of my, rather large, hand): took me a while to ID them, though, as they were "desert recluses", and lacked the telltale "fiddle".

They like warm houses, they love cardboard (for some reason), and they like warm, tight snuggly places, like underneath bedsheets (where I've found them on occasion in my parents house). They're not aggressive (whatever that means for a spider), but they certainly put themselves in the way of humans with considerably frequency.

The reason you haven't been bitten by a brown recluse is generally that what you have is a painful, itch spot, versus a gaping, rotting wound.


This happened to me, 4 years ago this month, although I misdiagnosed it myself as a simple spider bite. But the Dr. diagnosed it as MRSA. Took me a year and numerous skin flare-ups before I was able to kick it. I never want to go thru that ever again!


You really need to contact this guy:

He is literally the leading expert on these spiders in the country and his review of the data of over 20,000 spider identifications in CA came up with less than 10 brown recluses ever in CA, usually associated with cargo or recent travel. I am sure he we would be very interested to find out he has been missing the many your amateur entomologist parents have identified. In fact, I am sure he would get a paper published on it as he has many published about the brown recluse already. Your parents are about to be famous!

The desert recluse is a different spider. The above linked article talks about them as well.

The links along the left side are pretty good for a lot of the issue around brown recluses.


yeah, it wasnt a spiderbite dude...


That guy's sure got the hyperventilation cranked up to 11. "Brown recluse" is a common name, and like most people I'm more concerned with "loxoceles" generally, so concern about whether or not it's this or that subspecies is, well, academic.

And to his credit, he does point out:

In its native range, the brown recluse is a very common house spider.


I am sure he we would be very interested to find out he has been missing the many your amateur entomologist parents have identified. In fact, I am sure he would get a paper published on it as he has many published about the brown recluse already.

They live in Arkansas, he would not be interested, and they are already published, thanks.


This happened to me a year ago. Hand swollen to paralysis from what the doctor determined was likely MRSA-laden spider bite. I assumed it was a brown recluse until an entomologist friend told me Washington state does not have brown recluses, and in fact most spider bites blamed on the recluse are from hobo spiders. Now I see them everywhere...


Ah. I see. I misunderstood you on that.

Sub species is not academic. Brown recluse is not a common name for spiders in general, it is the common name of a specific species of spider. Just because you use it incorrectly doesn't make it irrelevant, it just makes you a contributor of misinformation about the brown recluse.


Mmmm, abscesses! POP!


from the species Aracnid Mersanuas


Yeah they are all over Missouri too. We kept noticing a ton of spiders in the house, some were brown recluses and some were what we call wolf spiders. We got a bunch of sticky traps and put them everywhere and it was amazing how many of those bastards we caught. Between the traps and having the house sprayed once, we more or less got rid of them.


This article is dead on.

I'm a physician assistant (and erstwhile amateur entomologist), and I had a MRSA infection several years ago. It was the most instructive malady I've had to date.

The reason most people assume they were bit by something is that when a MRSA infection begins, it commonly starts in a microtear in the skin, often in a hair follicle. For the first day or so, the primary symptom is a raised, itchy weal—which appears EXACTLY like an insect bite. After that first day, it morphs into a pustule and looks more obviously like a bacterial infection. Thus, people (and many clinicians) assume they've been bitten by an insect, and that said bite later became infected. My own experience, and Occam's Razor, tell me otherwise.

That being said, people generally find the MRSA concept extremely frightening. The vast majority of "infected spider bites" are MRSA infections which are contracted by merely coming into contact with the superbug through normal everyday activity. Yes, your environment can sicken and kill you. Even without spiders.


You're also quite likely to live in a place where there are no brown recluses to bite you.


So a possibly dumb question here: Something bit me, and I assumed it was a spider, because it turned in to a kind of bulls-eye effect about 2" across that was slightly itchy/sore and lingered (changing colors) for 2-3 weeks. It didn't seem serious (I'm sure it wasn't a brown recluse!) so I didn't have it looked at. Do you spider-knowledgeable folks think it was a spider bite? Should I have worried about it? What about ticks? (I have a cat).

Sorry, I know I shouldn't post this kind of thing, but now I'm just curious...


A "bulls-eye" shape is a telltale symptom of Lyme Disease. I'd get a doctor to check you out (and your cat and home checked for ticks), it can lay low for a while, but when it comes back, Lyme gets NASTY.


Thanks to Dr. G Medical Examiner, I was familiar with the concept of people mistaking MRSA for a spider bite. What I didn't realize is that doctors are not necessarily any better than the general public at telling the difference.