“…Various hypotheses have tried to explain the pathophysiology of this phenomenon, claiming structural or microenvironmental changes in the spared skin. Knowing the diversity of conditions implicated in the different cases reported (table 1) [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32], the mechanisms implicated might be multiple and complex.…”