The picture at the top is a rash that developed on my hand the other day after being in the sun for five minutes. I have since had some amount of the rash for going on three weeks and am seeing a dermatologist for it, but it made me think about the things a rash can teach us about biology and microbiology. I was thinking about this because one of the hardest things I have to try and get across to students about science is that you have to go in with an open mind when trying to actually do science.
My dermatologist is currently trying to decide if the rash is the result of a benign condition called Polymorphous Light Eruption (PLE, a hyper-reaction to UV radiation common in people during early spring) or an autoimmune condition called Dermatomyositis (DM, an autoimmune condition where the body attacks it own skin and muscles). Either way it results from my immune system responding to UV radiation in an inappropriate manner and requires some steroid treatments to fix.
I bring up this rash because every year I ask my BIO220 students about how Dr. Sterne first discovered that Lyme disease was an infectious disease. The answer is fairly simple, that the disease was treatable with penicillin, yet a majority of students miss it. The majority of students opt for the distinctive rash of Lyme disease meaning it is infectious. I know most students intuitively realize that a rash is not, by itself, an indicator of infection (think poison ivy, psoriasis, or eczema), but the students get tunnel vision and fill their heads with visions or measles or Lyme disease before they think through the question.
The take home message is that you need to spend a moment in my classes to think before you answer and learn to rely on that huge amount of intuitive information you have access to.