A 19-year-old boy with a history of seizure disorder presents to the nurse practitioner with symptoms of a high fever, a macular rash, and pharyngitis. He says he thinks he has strep throat, but the rapid test is negative for Streptococcus infection. This patient was started on phenytoin 2 months ago. Which of the following is the most likely explanation for his symptoms?

Choice A reason: DRESS syndrome is a severe drug-induced hypersensitivity reaction that typically occurs 2–8 weeks after starting a medication like phenytoin. It presents with fever, rash, lymphadenopathy, pharyngitis, and internal organ involvement. The timing and constellation of symptoms in this patient strongly suggest DRESS. Choice B reason: Gingival enlargement is a known side effect of phenytoin but presents as painless gum overgrowth, not systemic symptoms like fever or rash. It does not explain the acute illness described. Choice C reason: Toxic epidermal necrolysis is a life-threatening skin reaction characterized by widespread epidermal detachment and mucosal involvement. While it can be caused by phenytoin, the patient’s rash is macular and not consistent with the extensive skin sloughing seen in TEN. Choice D reason: Purple glove syndrome is a rare complication of intravenous phenytoin administration, involving painful swelling and discoloration of the limb. It does not occur with oral phenytoin and does not match the patient’s symptoms.