Man with an unfortunate target lesion on his back

Luckily beauty is only skin deep, because this rash was a beauty. Classic red rings, each containing another red circle centrally—named ‘target’ lesions after the chain store logo.

“Erythema multiforme!” I announced with an Ancient Greek twang. I guess the original dermatologists were embarrassed to name any rash ‘lots of red shapes’ in English. “It’s a beauty,” I confirmed.

He looked at me dubiously. Perhaps the eye of his beholder didn’t see it. “Anything I need to avoid, doc?”

I studied the hundreds of bullseyes adorning his skin. “Duck shooting season. Next please!”

I love a good rash.

Unlike inflammation on our inside body-parts, every variant has its own 200-year-old name—and decent names, too. Contrast this with hepatitis, where for all we know each virus might cause a distinctive rash on the liver, but because we can’t see it they just get alphabetised.

No, Hep B and C have nothing on slapped cheek disease. What a ripper! Visions of red-faced orphans in Dickensian London lining up in front of the perplexed physician, and Mr Bumble claiming he never touched ‘em.

Consider the portmanteau word frostbite: it is magnificently descriptive. As is geographic tongue, where regions of smooth skin resemble a map. If this worsens, even better— it’s called scrotal tongue. I like to ask med students how they think you catch it.

Yes, rash names simply tell it like it is. Even struggling students can stave off failure for minutes when asked to describe red man disease or hand, foot and mouth. But I find baboon syndrome soon sorts them out. Most are too scared to correctly guess ‘bright red buttocks’ and instead opt for excessive chest hair or something necessitating the de-lousing of one’s sexual partner.

I shouldn’t taunt them so, but I remember suffering through the world’s grumpiest dermatologist quizzing us on acrokeratoelastoidosis back in the day. No surprise when I later learned his profession invented prick tests.

Students struggle with rashes; even as a GP it takes years to imprint the patterns onto your brain. (Did I mention my theory that encephalitis does the same thing, but we just can’t see it?)

Regardless, the ability to name viral rashes is merely showing off, because the treatment for every patient is identical: give them one week to pay their bill.

As a GP, all you have to remember is that if it’s dry, wet it; if it’s wet, dry it; and if you don’t know what it is, try steroid cream.

Finally, if it lasts longer than a week, dermatologists have invented a special word to insert in front of your original guess: idiopathic.

First published in Medical Observer, March 2014