Click here to view next page of this article

Spider Bites and Stings

Spiders. There are about 30,000 species of spiders in the world but only about 50 of those species bite humans, and although they may be painful, most have no medical sequelae either because the spiders have short fangs, small fangs or inadequate venom. So although they might hurt and people might say, "I’ve been bitten by a spider" most of them don’t have much medical importance that you have to worry about. The biting part of the mouth of the spider.

Six species in the United States are capable of delivering necrotic bites, and the necrotic bites are the ones that we are most concerned about and the ones that we worry about, and obviously are the worst problem for the patient. Those are the ones that lead the sequelae and also cause quite a bit of pain. There are two genera in the United States that produce life-threatening bites. The violin backed spiders, particularly the Loxosceles, the Brown Recluse-type spiders and the black widow spiders. But garden spiders will produce a painful bite.

Wolf spiders are very common, they are very ugly spiders and they also produce a very painful bite. And they are very scary so somebody is going to really be upset if they get bitten by a wolf spider. There is something called a Hobo Spider, which has just started to be seen in the Northwestern part of the United States, and it’s going to be a pretty bad one, I think. Aggrestus, second part of it’s name, suggests that it is a little more aggressive.

This is the distribution of these spiders in the United States and this is from the CDC/MMMR report and it discusses the so-called Hobo spider, Tegenaria aggrestus. And this is the area that the Hobo spider has been reported in, but as you can see, it’s kind of creeping down.

There are thirteen species of violin backed spiders. The Brown Recluse is the Loxosceles reclusa. It’s been reported in all 50 states so nobody is escaping it. But it’s more common in Tennessee, Arkansas, Missouri and Kansas and that’s where the most reported bites have been. The most reported necrotic bites. They are about 1-6 cm in size, light tan to dark Brown, they key is a small body with the long thin legs, because they are very recognizable.

Here’s one right here. As you can see, it has long spindly legs, kind of a tiny slender little body. If you can appreciate that, here’s the violin, right up here and here’s the stem of the violin. This is what you see a lot, which is a crushed spider. And as you can see, if somebody describes that he’s going to say, "Oh, I saw the legs." So a lot of times that’s what the patient is going to say.

Okay, what about the Brown Recluse spiders? They are very shy and nocturnal and non-aggressive, so you have to go to where they are. They don’t usually come to where you are except to hide. They live in dark places; woodpiles, cellars, unfortunately closets, and unfortunately clothing folds, because that’s usually how you get bit.

How do you treat them? I’m suggesting medical management is the treatment and not do surgery until it is completely healed. And then just if you want to repair it. The treatment: Lloyd King at Vanderbilt has come up with some of this. His idea is the so-called RICE, which is rest, ice compresses and elevation. I would say if I had one thing to treat any kind of bite with it would be ice. Ice can take something that is going to be horrendous.

I’ve talked about this actually because I have these spiders where I live. I think this is the best way to get rid of them because they are big, spindly spiders. Their abdomens don’t cross and spray so it’s really hard to get rid of them. What this is, is this is a trap and this is against the wall where they walk, and here’s one and here’s one.

Okay, Brown Recluse spiders. I usually treat them until the redness goes away. If there’s any redness left I continue them on it. In terms of erythromycin, obviously that’s a safe drug. If I see somebody that comes in that I think has a bite but I’m not sure it’s a spider bite, I’ll do the ice and I’ll do the erythromycin, I won’t do the Dapsone. But if there is a Brown Recluse bite I will put them on the Dapsone.

Dapsone inhibits polymorphonuclear leukocytes. That’s the main function of it. Although I’ve put up the sphingomyelin as one of the … probably the active ingredient that causes the necrosis, it may be that it’s poly’s that