The chief complaint of a thirty-five-year-old man was that he was “in chains.” Indeed, he had been brought in handcuffs and ankle chains to our clinic from the local jail. The officer's key freed the man's arm so the blue prison shirt could be slipped down to reveal the problem. There we saw on the outer side of his right arm a band of tense blisters, extending all the way from his shoulder to his hand. We deferred examining the rest of his skin in deference to the two anxious police officers.

This happened during the first month of a three year residency program when our diagnostic horizon was limited to what we had seen in the medical school clinics. However, we were proud of this, because each week of our senior year our professor of dermatology had demonstrated thirty patients, which our class could then examine at close range for the hour after the lecture. On graduating we knew more about diseases of the skin than any other organ.

We knew that the most common cause of the big blisters this man exhibited would be poison ivy dermatitis or sunburn. But the prison cell admitted very little sunlight and he could not have come in contact with poison ivy in the last few days. Could it be self-induced? Or, could it be a drug allergy? There was no evidence of a chemical or thermal burn and he had no access to drugs.

But surely, the location told us something.