This next in a series of quick quizzes in dermatology asks -what’s the cause of this itchy, vesicular rash on the hands?

A 52-year-old male. The patient has a history of dry skin, but in the last 2 years his hands have broken out "bad" (Figures 1 and 2). It was at its worst last winter, but is now constant. He complains ...

The patient is allergic to N-isopropyl-N-phenyl paraphenylenediamine, an ingredient in black rubber [1] which is used in the manufacture of tires, scuba masks, and the industrial gloves he wears at ...