Friday, March 9, 2018

The Spider Bias

Image result for charlottes webPoor Itsy Bitsy.
Poor Charlotte.
Poor Miss Spider.

All Itsy Bitsy did was climb up the water spout.

Charlotte saved Wilbur's life.

And Miss Spider-- remember her from Roald Dahl's James and the Giant Peach?--she was a kind and gentle soul to poor little James. Miss Spider says it best: "I am not loved at all. . .And yet I do nothing but good. All day long I catch flies and mosquitoes in my webs. I am a decent person. .  It's very unfair the way we spiders are treated."

Human beings' blame game with spiders is one of the strangest and most pervasive cultural biases I have discovered in my role as a family physician. Without evidence. Without a trial. Without a second thought. We believe spiders bite us. All the time. We see them around, we assume they are evil, and we blame them for strange otherwise inexplicable skin eruptions that have nothing to do with them.

The story goes something like this: 

Mr. human wakes in the morning with a sore red spot on his body. It may even have some pus. It hurts. He has no idea how it got there. He wants to know. There must be a reason, an identifiable cause. Incidentally, there are spiders in the world. In fact, the human saw one in the last week in his very house. Spiders are known to be evil. They bite. That's it! The spider did it. Case closed. 

This bias is surprisingly widespread. So much so that on any given day in any given emergency room, urgent care, or outpatient clinic in America, you will find someone reaching out for care for a "spider bite" caused by a spider they never saw. 

31 year old, spider bite, R arm (see photo)  

7 year old, spider bite, abdomen (see photo)
56 year old, spider bite L thigh (see photo)
2 year old, spider bite, leg (see photo)

Image result for mrsa abdomenImage result for mrsa infection
Image result for mrsa cellulitisImage result for mrsa furuncle

Sometimes the 31-year-old is a drug addict, but he could be a veterinarian. The 7-year-old might have a dog or perhaps a bearded dragon. Sometimes the 56-year-old has had one of these bites before. Out of curiosity and playfulness, my first question for such patients is always "Did you see the spider?" The answer is always no. Did you catch that? No one has ever seen the spider. Occasionally, the "no" is followed by an "Ahem, well, a few weeks ago I did see one. I saw a spider."

Now, put yourself in the place of a spider, just for a second; what it must feel like to be blamed when you weren't even seen in the building since last week? What it must be like to be assumed at fault by an entire nation? This is a classic case of guilty until proven innocent-- and a cultural belief so strongly held that a review of the case (much less a trial) is deemed unnecessary.

Poor spiders!

In my ten years as a  family physician in Northern California, I can definitively tell you that while I have seen plenty of patients who believed they had a spider bite, I have never actually seen a spider bite. Not once. Not a single time. One study in Southern California found that of 144 people seeking care for a spider bite, only 3 had an actual bite (that's a whopping 2%) . 

In my (albeit anecdotal) experience, 100% of presumed spider bites have turned out to be either small pustules or larger abscesses from a cutaneous bacterial infection (i.e. a skin infection). These infections are famously caused by staph aureus, and most often a newer antimicrobial resistant strain called methicillin-resistant staph aureus (aka MRSA). Turns out somewhere upwards of 25-30% of humans have staph aureus living on their skin (sorry if you didn't want to know that), and about 2% of us have MRSA. 

Our skin is our major defense mechanism; it protects us from burns, cuts, and infections. And yet, the barrier is constantly being challenged in both major and minor ways. With relative frequency, we nick ourselves on a piece of paper or with a sharp object and know exactly when it happened, but much more often, we have micro-perforations of our skin barrier-- little nicks that are so small we don't even realize they happened. These micro-perforations make us vulnerable to our own commensal skin flora hanging out on our skin,  thereby turning a mutually neutral existence into a bad relationship. 

Usually, our remarkable skin spontaneously heals itself after such a perforation, and we go along our merry way. But occasionally, when the conditions are right, skin disruption meets staph aureus (or even worse, MRSA), and infection ensues. That means occasionally someone actually did have a bug bite that got infected or a preexisting scratch that turned into an abscess, but more often than not, there was no obvious initiating factor. 

Such infections are no fun-- I have had a few and treated many. They are painful and embarrassing and can make you quite ill. Often, they need antibiotics or drainage (think: scalpel). Recently a perfectly healthy young friend of mine was hospitalized for just such an infection. 

My husband once wisely said to me that people blame spiders for skin infections because it's less scary than knowing the truth-- that is, that our own friendly bacteria are capable of creating what could become a serious infection-- and that it could happen to anyone at any time. It's freaky, he said, to imagine that there isn't something (or someone) else to blame.  Spiders are an easy target. 

What can you do to prevent abscesses and skin infections? Take good care of your skin. Wear gloves when indicated. Wash your hands. Don't scratch. Don't pick. Keep your fingernails short. Keep your skin well hydrated (with a good lotion or cream) and pay attention to any particularly dirty cut or scrape as soon as it happens. Even so, occasionally things will get infected. Soak them (in a basin or with a hot compress) and talk to your doctor if the redness or swelling is worsening.

What else can you do?

An even harder undertaking is to stop blaming the spiders, to start questioning our own biased assumptions, and to practice tolerance. 

As we stumble through this complicated life, overwhelmed with fake news and social media-driven hyperbole, we should reserve blame-- for blame often enough will lead us to be more fearful and less curious.  

Image result for charlottes web quotesWe should also continuously ask ourselves if our primary assumption is true.  In fact, it turns out that only about a dozen of the more than 40,000 species of spiders worldwide can actually cause harm to humans; and even the ones we know are bad (e.g. the black widow and the brown recluse) cause less harm than we might think. Just like Miss Spider said, spiders are mostly beneficial to humans by eating many insects that either infest our foods, are disease vectors, or are just plain annoying.

And we should practice tolerance. For being intolerant of spiders does nothing to decrease one's risk of a skin infection but does increase one's anxiety. Practicing tolerance allows us to peacefully coexist with other living creatures-- which sure sounds more pleasant than living in fear. Plus, you never know when you might be grateful to have a spider around. Right, Wilbur?

Roald Dahl's James and the Giant Peach
EB White's Charlotte's Web