A 15-mo girl with no PMHx developed cough, fever, and conjunctivitis 1 day after her first MMR vaccine. Four days later, she vomited, and a rash developed behind her ears, spreading to her face and trunk. Exam showed tiny white papules on her oral mucosa. What is it?
Varicella
Measles
Parvovirus B19
Drug eruption
Idiopathic thrombocytopenic purpura
You are correct. Her initial prodromal symptoms followed by the progression of the macular-papular rash are typical for measles. Koplik spots, small white lesions on the oral mucosa, are considered pathognomonic. Fever and rash within 5 days of vaccine are unlikely to be vaccine related. RT-PCR of oral fluid confirmed wild-type measles. She was treated with acetaminophen and ibuprofen and made an uneventful recovery.