Acrodermatitis Chronica Atrophicans
I saw a little old man with a rash on his feet. Actually, his blood pressure was also off the wall (because he'd run out of his meds long ago) and his liver function tests had been way out of whack the last time I'd seen him. He'd never come back for me to work them up, so when he finally showed up again I was really worried that he was riddled with cancer or something.
To my surprise and relief, his LFTs were perfectly normal, and his BP came back down nicely once he re-started his meds. But he kept complaining about this rash on his feet.
He said it was painful, with a burning quality. It had been there for several months and he didn't remember much about how it began. On exam, the tops of his feet revealed a very well-demarcated area of redness, with some skin thinning (increased visibility of blood vessels) but hard to tell because the skin on the dorsum of the foot is very thin anyway.
I struggled to get a history of something he had used topically -- lotion or something -- or sandals he'd worn in the sun. I could have sworn it was some version of contact dermatitis because the rash was so well-defined. (There's a saying I made up: "Dermatology is like real estate: location, location, location.") I tried various forms of topical moisturizers and steroids; nothing helped. Finally he asked for a referral to a dermatologist, a request I did not find unreasonable.
The dermatologist sent him back for a blood test: a Lyme titer. Frankly, I thought the patient had sustained a tick bite between seeing me and the derm, and the derm wanted to rule out ECM. Imagine my surprise when the Western blot came back with every single band positive for both IgM and IgG. I even got a phone call from the derm, letting me know the rash was a "classic case" of acrodermatitis chronica atrophicans, a manifestation of late stage Lyme disease (and he had called in all his students to take a look.)
I had never heard of it.
But I went and looked it up [contrary to the epithets hurled by the latest batch of chronic Lyme disease groupies, I do read and research things for myself] and sure enough, there it was. As it happened, none of the pictures I saw really looked anything like my patient's rash, so I'm not beating myself up over it. Still, it was interesting to learn something new.
The rest of the story is a bit of a downer: we'll treat him with antibiotics for 21-30 days, but chances are at this point that the damage has been caused by B. burgdorferi antibodies and not by the organism. Still, we'll tell ourselves we're killing whatever's there. The other problem is that antibiotic treatment may not help the burning pain, which is apparently considered to be neuropathic in origin. I'm going to try him on some neurontin and hope for the best. The dermatologist concurs.
I don't disagree that Lyme disease can be a nasty condition, with protean manifestations and long range problems if unrecognized and untreated. However it needs to be made very clear that LATE Lyme disease (skin, joint, heart and neurological symptoms) is not the same as CHRONIC Lyme disease (a nonsense label given to syndromes consisting of vague subjective symptoms of pain and fatigue.) I feel bad for folks suffering from the symptoms labeled "chronic Lyme", but the true complications of late Lyme disease will always keep us on our toes.