Sunday, November 21, 2010

Look At That Spider Bite Again

This is a true story.Doctor: “What problem are you having?”Mother (pointing to her son): “He has a spider bite on his arm and it might be a brown recluse."Doctor (examining the lesion): “Did you see a spider bite him?
Mother: “Well, no, but some of his teammates have spider bites from spiders in the locker room."
Doctor: “Why do you think it was a spider?”
Mother: “Because it looks like a spider bite.”
Doctor: “I’m not sure what you mean. What about this lesion on his arm looks like a spider bite?”
Mother: “See the two dots in the middle?”
Doctor: “This is not a spider bite. It is an infection. Probably Staph infection .......”
Mother (pulling son arms): “Come on. Let’s get out of here. This doctor doesn’t know what he’s doing. Those other boys on your football team were told this week by their doctor that they had spider bites!”
Two weeks later local newspaper headline – “FOOTBALL TEAM HAS STAPH INFECTIONS, Health Department Consulted.

The hysteria of spider bites continues although it has been said repeatedly that brown recluse bites are rare. Even rarer is the destruction of muscle tissue shown in the graphic pictures shown everywhere. Most spider bite diagnoses are made by looking at the wound (not reliable), without the person seeing the spider bite them, or catching a spider for identification. This has greatly increased the number of alleged spider bites. And it’s not all the public’s fault. Physicians are quick to diagnose a wound as a spider bite. One physician I know told me that it is easier to agree with the patient that it is a spider bite than to try and explain and convince them otherwise. “I just say ‘Oh, you are right’, and then give them an antibiotic that covers staph (MRSA). Most of the time they are also agreeable to getting a culture of the ‘spider bite’.”

One study found hundreds of patients diagnosed with brown recluse spider bites in California even though brown recluse spiders are not located there (see map). Some have been very very rarely (less than 10) found in California, usually the result of transporting on shipments from their usual location. There are other types of Loxosceles in southern California (see map)

Consider this: A homeowner in Lenexa, Kansas collected 2,055 brown recluse spiders in his house, for six months in 2001, and had them verified as actual brown recluse spiders. NONE in the family of four members received bites from the spiders. If none of those living in a house with over 2,000 brown recluse spiders were bitten, how many brown recluse spider bites would occur in states and areas that are not know to have these spiders? You would expect to find thousands or even millions of brown recluse spiders in South Carolina, Florida and California to justify the many diagnoses of brown recluse spider bites in those states.

940 physicians in South Carolina, responding to a survey, reported 478 brown recluse spider bites in the state for 1990. However, South Carolina is outside of the native range of the brown recluse spider and an arachnologist looked for brown recluse spiders intensively for five years in South Carolina and never found a brown recluse spider or had anyone bring him one.

21 counties in Florida had 95 brown recluse spider bite diagnoses in the year 2000. Florida's arachnologists report that no brown recluse spiders had been found in these 21 counties.

It is not uncommon for some in Kansas to find more brown recluse spiders in their house at one time than have been found in California in the last 40 years! Someone in Missouri has a good laugh every time a news report in California states that a brown recluse spider may have been found. It seems that those living outside the brown recluse spider’s habitat are dedicated to having the brown recluse spider live in their area!

The spider is named “recluse” for a reason. It is shy and rarely bites. The spider’s web is not out in the open. To be bitten, you usually have to find the spider and be a threat as the spider does not go looking for you. That means putting on clothes that have been laying around which presses your skin against the spider, putting on shoes or gloves which the spider had gone into to be a recluse, rolling over on bed sheets and onto the spider, and picking up old boxes with your hands smashing the spider.

Don’t get me wrong, rarely brown recluse spider bites can lead to serious problems and should not be ignored, but most households containing brown recluse spiders never have a bite. 90% of all brown recluse spider bites heal without scarring. Many brown recluse spider bites only cause a small red mark that resolves without problems.

Loxosceles (genus), the recluse spiders (13 species found so far in the US). They have six eyes and some have poisonous bites. Here are some of the species names:
Loxosceles recluse (Brown Recluse spider)Loxosceles deserta
Loxosceles apachea
Loxosceles arizonica
Loxosceles blanda
Loxosceles devia
I found an article on the internet that states that these are also found in southern California:
Loxosceles laeta (Chilean recluse), This spider is the largest of the recluse spiders found in the US and is strongly suspected of having the most "potent" venom.
Loxosceles russelli, (Russell recluse).
Loxosceles palma, (Baja recluse).
Loxosceles martha,(Martha recluse).
Loxosceles rufescens,(Mediterranean recluse).

Here is a good article on Brown Recluse Spiders

Here are some pictures of the Brown Recluse Spider

Here is a map of the range of the Loxosceles:

Things you can do to reduce the chances of being bitten by a brown recluse spider if you live in an area with brown recluse spiders.

Unless you see an actual spider bite you, here are some things you should consider before saying that it is definitely a spider bite. Some of the conditions that can cause necrotic wounds and/or that have been misdiagnosed as brown recluse bites are:
Infections with Staphylococcus or Streptococcus species
Herpes simplex
Herpes zoster
Erythema multiforme
Diabetic ulcer
Lyme disease
Fungal infection
Pyoderma gangrenosum
Lymphomatoid papulosis
Chemical burn
Poison ivy/oak dermatitis
Squamous cell carcinoma
Localized vasculitis
Syphilitic chancre