Polite Dissent

Rashes are fascinating. They are one of my favorite diagnoses to see in the office. It is amazing that the skin, a single organ, can respond in so many entirely different ways to a limited number of causes. Rashes can be red, blue, purple, red, white, brown or almost any other color of the rainbow. There are hundreds of textures, including bumpy, solid, flaky, or even slimy. There can be no pattern, a ring pattern, a swirl pattern, a Christmas tree pattern, or any of hundreds of other patterns.

Rash identification breaks down into three possibilities, all fairly equally spread. This gives us Scott’s Rule of Rashes:

1. One-third of the time I know exactly what it is. (“Why, that’s pityriasis rosea“)
2. One-third of the time I have a general idea of what it is, and a good idea of how to treat it. (“That looks like some kind of irritant dermatitis. We should be able to calm it down with a steroid cream.”
3. One-third of the time I have no idea.

I first formulated my rule of rashes when I started my career as an Air Force physician. As I’ve gotten more experienced and entered private practice, I find that the rule still holds true for the most part, although there’s less category 3 and more category 2 now.