Any recently appeared verrucous lesion of the nail unit in men above the age of 40 years should raise the suspicion of Bowen disease and lead to further histopathological diagnostic procedures.

lected, such as the excretion of amino acids in sweat and whether the amount changes in women during the menstrual cycle.Still to be explained is how the present patient had black dermographism that lasted 10 minutes and then disappeared without manipulation. To our knowledge, this phenomenon is unique to this patient; we conducted several informal experiments that found the discoloration always remained until removed with soap and water. If the reaction of metal with sulfur-containing amino acids in sweat is a viable theory, then perhaps changing concentrations of amino acids on the skin as sweat evaporates, and the resulting impact on gold dissolution, could explain the quick resolution of the black smudge. This observation leads to the reasonable conclusion that black dermographism has additional unexplained mechanisms that are perhaps innate to the physiology of certain persons.

No abstract