The reverse isotopic response is a rarely encountered phenomenon. The spared lesions are various and mainly inflammatory in nature, with herpes zoster infection being the most common. A novel case of Stevens-Johnson syndrome triggered by carbamazepine sparing the skin area previously affected by herpes zoster infection in a 39-year-old Indian female with systemic lupus erythematosus is documented. Several features as well as possible pathomechanisms that bear discussion have emerged from this case documentation. These may be related to the virus immunity, the underlying autoimmune disease (systemic lupus erythematosus) and/or drug metabolism.