Stevens-Johnson syndrome in a patient receiving anticonvulsant therapy during cranial irradiation

A 28-year-old female patient with a recent history of breast carcinoma was referred to our clinic with generalized necrotic skin eruptions and severe mucosal erosions, which developed right after the completion of cranial rad iotherapy for brain metastases. She had been receiving prophylactic dipheny lhydantoin treatment 100 mg three times daily during radiation therapy. The extensive involvement of the oral mucosa with conjunctivitis and synechiae of the eyelids, facial swelling, and extension of the rash over the trunk and shoulders with bullous detachment of less than 10% of the total body su rface strongly suggested Stevens-Johnson syndrome caused by phenytoin treat ment in our patient. There has been conflicting evidence on the role of rad iotherapy in the increased risk of severe drug reactions. Although various authors have emphasized the augmented rate of severe mucocutaneous reaction s caused by anticonvulsants given during radiotherapy and suggested discont inuing the prophylactic use of such drugs in patients with no history of se izures, others have argued in favor of prophylactic anticonvulsants. Given the high risk of seizures, reaching 20% in patients with brain tumors, and the low incidence of drug reactions, the suggestion of refraining from prop hylactic anticonvulsants in the setting of primary or metastatic brain tumo rs is controversial.