A case of hypersensitivity syndrome due to phenytoin

We report a 30-year-old female with hypersensitivity syndrome (HS) due to phenytoin. Her disease course was typical with elevation of the antibody titer for human herpes virus 6. Three courses of methylpredonisolone pulse therapy were required to control the disease activity. Since the pathogenic mechanism and treatments for HS have not been established, further clinical analyses are warranted.