RESUMEN
Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome and toxic epidermal necrolysis (TEN) are severe cutaneous adverse reactions. Although viral reactivation is associated with DRESS syndrome, its role in TEN remains unclear. An 80-year-old woman visited our hospital because of fever and skin eruption. DRESS syndrome was diagnosed and was thought to caused by the use of the drug allopurinol. She was treated by discontinuation of the drug and administration of systemic steroids. She recovered from DRESS syndrome and was discharged from the hospital with tapering doses of steroids prescribed. One week after discharge, she visited our hospital again as the skin rash recurred and oral pain as well as oral and ocular mucosal lesions developed. In addition to the skin rash, blisters and Nikolsky's sign that were different from the skin lesions present in the previous DRESS syndrome were observed. Unlike those in DRESS syndrome, the viral serological test results were positive for anti-cytomegalovirus (CMV) IgM and CMV polymerase chain reaction. Therefore, it was thought that TEN was due to reactivation of CMV and she was treated this with ganciclovir and intravenous immunoglobulin. Here, we report a case of TEN caused by viral reactivation after DRESS syndrome developed after use of allopurinol which recovered after steroid treatment.