As the old saying goes, “If I had a nickel for every time [something happened], I’d be rich.” For a dermatologist, the [something happened] stands for “Help—my back itches, Doc!” How often do I hear ...

The itch crept up my back, across my stomach and along my arms and legs. It flared during my morning runs and followed me to the office. It was particularly acute at night. I was covered in marks from ...