In the 19th Century, RobertWillan (Fig. 7) and Thomas Bateman,who are regarded by some as the fathers of modern dermatology,divided acne into four types based on the associated lesions: simplex,punctate, indurate, and rosacea (McCaw, 1944). The first three typeswere identified as local lesions that require local remedies; however,rosacea was deemed a cutaneous manifestation of underlyingstomach or liver problems.In 1903, the etiology of acne remained uncertain. Eduard VonJacobi (1903) wrote in Atlas der Hautkrankheiten that “many morbidprocesses conspire to favour the existence of the disease,” “a peculiarseborrhoeic condition is frequently present, which gives rise tothe formation of comedones.” He continued that “specific significance