Title : Delayed diagnosis of measles in an unimmunized child
Abstract:
Background:
Measles was declared eliminated in the United States in 2000 due to widespread administration of the 2-dose measles-mumps-rubella (MMR) vaccine. However, this vaccine preventable disease has reemerged in recent years due to declining vaccination rates and increased international travel. In 2025, the United States reported the highest number of measles cases in over three decades, with 1,281 confirmed cases as of July 7. Delayed diagnosis is common as early symptoms overlap with other pediatric illnesses. This leads to multiple healthcare encounters, protracted courses, and as a result, increased risk of both community and nosocomial transmission. We present the case of a partially immunized 5-year-old girl with delayed diagnosis of measles.
Case Presentation:
A 5-year-old girl with incomplete immunization and recent travel to Russia presented multiple times to the emergency department (ED). On initial presentation she had five days of fever, sore throat, nasal congestion and conjunctivitis. Rapid streptococcal testing was negative but early otitis media was suspected, and she was discharged on oral amoxicillin and a topical ophthalmic antibiotic. On day 8 of illness, she returned with persistent fevers and a new cough; a respiratory viral panel was negative and she was again discharged with supportive care. On day 9 of fever, she returned to the ED with a diffuse maculopapular rash, bilateral non exudative conjunctivitis and red/cracked lips. Review of her vaccination records revealed that she had not received any MMR vaccines. The differential diagnosis included atypical Kawasaki disease and measles and thus she was admitted to a negative pressure room. Due to morbidity associated with untreated Kawasaki disease, she was treated with IVIG and underwent echocardiography, which was normal.
On day 11, urine and nasopharyngeal PCR confirmed acute measles infection. She improved clinically, received oral vitamin A supplementation, and was discharged to continue isolation for one more day and supportive care at home. Appropriate post exposure prophylaxis was offered to all unimmunized and immunocompromised exposed patients the moment measles was suspected, even prior to confirmatory tests.
Discussion:
This case illustrates the diagnostic challenges of measles. Early nonspecific features mimic common viral infections, while later findings may resemble Kawasaki disease, potentially delaying diagnosis. In this patient, recognition of measles was not considered until the third ED visit, highlighting the importance of maintaining a high index of suspicion, particularly in the context of international travel and incomplete vaccination. Delayed recognition increases the risk of transmission in the community and healthcare setting, emphasizing the critical role of rapid isolation and public health notification.
Conclusion:
Measles should remain a key consideration in all children presenting with fever and rash, particularly those with a recent history of travel uncertain vaccination status. Early diagnosis, strict isolation, and timely reporting are essential to reduce transmission and prevent outbreaks. This case highlights the importance of careful vaccine history verification and vigilance in the current era as the incidence of measles continues to rise.
