Isotopic response is the occurrence of a new unrelated disease that appears at the same location as a previously already healed disease. In 1995, Wolf et al defined a this new phenomenon and reported eight new cases with fiftyeight cases corresponding to the definition for this phenomenon in literiture. We report two cases considered as isotopic response, urticarial vasculitis and erythema multiforme developed on striae distensae, respectively. (Kor J Dermatol 1996;34(4): 664-667)