Phenytoin-induced toxic epidermal necrolysis in a pediatric patient

We report on a 6-year-old boy with history of tuberous sclerosis and inaugural drug resistant focal epilepsy that required a sequential therapeutic step-up in order to achieve symptomatic control—he was first started on levetiracetam, adding phenytoin 13 days later owing to maintenance of symptoms. After Neurology reevaluation 9 days later, levetiracetam was switched to perampanel. Two days later, he developed a rapidly progressive and confluent erythematous-violaceous maculopapular exanthema, mildly pruriginous, without mucous membranes or palms/plantars involvement, followed by persistent high fever, unresponsive to antipyretics. There were no other associated signs and symptoms. Following evaluation in the emergency room, both drugs were suspended, and analytical evaluation revealed neutropenia, eosinophilia, thrombocytopenia and aspartate transaminase, alanine aminotransferase, and lactate dehydrogenase elevation. No infectious agents were identified, specifically Mycoplasma pneumoniae, and serologies for herpes simplex virus, hepatitis A virus, Epstein-Barr virus, and cytomegalovirus were negative. About 8% of his body surface area was involved at this stage and he was admitted to the ward under prednisolone (2 mg/kg/d) and rectal diazepam for acute treatment of eventual seizures. Avoidance of phenytoin and other aromatic anticonvulsant medications was recommended owing to the high degree of cross-reactivity.