You swear you’ve been bitten by a spider. Naturally you didn’t see the 8-legged critter – you were sleeping. But there are spiders in your house and you spent a lot of time cleaning cobwebs over the weekend. When you notice a red bump that looks like a bug bite, it’s only logical to think that it’s a spider bite. But when the little red bump becomes larger and redder you ask yourself if perhaps it was a poisonous spider. Or maybe you’re allergic to spider bites. When the spot becomes large enough, you decide to see your doctor.
The above is a common scenario, sending thousands of patients to their doctor each week. But if you go to your doctor with the above story, your doctor will likely say the lesion is not a spider bite.
Why? In recent years a new infection has been spreading that has the appearance of what people assume is a spider bite. This infection, community-acquired methicillin-resistant staphylococcus aureus, or MRSA, is not really new. It’s been around in hospitals for decades, but in recent years it has moved into the community. Luckily, it’s generally not as severe as that seen in hospitals, in part because its victims are usually healthier than hospitalized patients, and also because the bacteria itself is somewhat less aggressive.
MRSA presents most commonly as a skin infection, but over the past few years I have seen other infections caused by this microbe including pneumonia, urinary tract infection, and bowel infection. However, it has the potential to effect any body part.
The problem with this infection is that antibiotics that normally work to kill staph germs do not necessarily kill off MRSA germs. Specifically, antibiotics that are usually chosen to treat staph infections (methicillin and other forms of penicillin) will not work. Nowadays if a staph infection is suspected, your doctor may treat you with two different types of antibiotics until the results of a culture are available. If there is a high prevalence of MRSA in your community, your physician may choose an antibiotic to treat this specific infection from the outset.
What’s the big deal about a staph infection? A lesion the size of a bug bite may heal itself if you have a good immune system. However, the risk is that it will spread to your blood stream, your bones, your heart, or your lungs – all potentially fatal infections.
Don’t take a chance. If you think you have a spider bite, and didn’t actually see the spider bite you, go to your doctor. There are effective antibiotics. It’s not worth dying in case you were wrong.
Copyright 2010 Cynthia J. Koelker, M.D.