Black Widows

Everyone in Fort Worth who has an abscess was ‘bitten by a spider’. It’s a given that this will be the explanation, and it makes sense (people want to explain things, especially if it’s on their body and hurts).

Sometimes, it really is a spider bite, and occasionally they bring it in:

These folks don’t have an abscess, by the way, they haven’t had time for that to develop. They’re either worried about what could happen, or they have the actual Latrodectism, or symptoms of envenomation.

Here’s a nice table, lifted from the Texas Department of Health’s Venomous Spider page:

General Black Widow Spider Envenomization Symptoms

  • abdominal cramping
  • abdominal rigidity
  • convulsions
  • headache
  • lesion at site of bite
  • nausea
  • pain
  • profuse sweating
  • tremors
  • unconsciousness
  • vomiting

The ‘profuse sweating’ I haven’t seen, and wonder if they misunderstood one of the unique clinical features of the black widow envenomation: localized perspiration around the site of the bite, only. It’s a nice teaching point, though the patient never seems to appreciate how interesting it is.

There are a range of treatments for this, and it’s very very rarely fatal (I found one reference that said less than 1%, but that’s just a guess, as even if it’s a real number from a study it’s only studying people with known bites). I personally have had about 5 patients with Latrodectism, and they’re truly miserable and appreciative when you make the symptoms a lot better.

(I have a friend who had this, and after 20mg of IV valium was still having severe abdominal wall cramping. He then got the antivenin, and says 10 minutes later his cramping was essentially gone. He was then kept in the hospital for the next 18 hours because he was so sedated from the valium).

If bitten by one, just come on in to the ED, we’ll treat you without the spider.

Oh, and I can’t resist reproducing this table, from the TDH website just below the Black widow one, for Brown Recluse:

General Brown Recluse Spider Envenomization Symptoms

  • chills
  • fever
  • nausea
  • necrosis at the bite site
  • nothing
  • red white and blue lesion at the bite site
  • restlessness
  • weakness



  1. good post!

  2. Ah yes… the famous “spider bite” that’s actually an MRSA cutaneous abscess (ours are virtually always community-acquired).

    The Loxoscelidae family contains a couple of species, including the common brown recluse, Loxosceles reclusa. They’re absolutely the most maligned spiders in my clinical practice, even if actual bites are exceedingly rare.

  3. He never saw a spider on his leg, but my husband had a dime-sized “red-white-and blue” lesion on his shin one evening which proceded to become necrotic and increase to the size of a 50 cent piece over the following 24 hours. When I dragged him in to a local urgent care center for treatment, the doc prescribed antibiotics. There was no abcess to I&D, just this ugly black spot. It did stop growing within 24 hours of initiation of antibiotics. We don’t live in brown recluse territory, and I don’t think the damage was quite severe enough in any case, but we do have a lot of assorted spiders around here and I sometimes wonder if it might have been a relative.

    OTOH, we have seen Black Widow spiders in the back yard. They’re really pretty and much larger than I’d expected.

  4. Jim in Texas says:

    When I lived in the high desert of Southern California Black Widows were everywhere and it’s wasn’t uncommon to kill three or four inside the house every week. Outside was (obviously) even worse.

    I had a Shepard/husky mix dog, about 50 lbs and she used to eat the damn things like they were salsa chips and dips. Frequently the spider got off one of those “defiant moments” on the way down and stung her mouth. Her mouth would swell up but it never seemed to do her any permanent harm. After the first visit to the vet. we never took her in again. She lived to the ripe age of 11 when cancer got her.

    We also had vinegaroon scorpions that would give you the heeby-jeebies.

    They were rumored to be poisonous and if they stung you, you would have the taste of vinegar in your mouth. It turns out they aren’t poisonous, but that they’ll spray a vinegar cloud at you…still gives me the heeby-jeebies.

  5. Great post. Informative and entertaining. Not a topic you see talked about very much, particularly by docs who see it. Will look for your next post on snake bites :)

    (I’d have used trackback if blogger supported it.)