Measles Diagnosis and Management

Diagnostic Criteria

The Centers for Disease Control and Prevention recommends diagnosing measles clinically with fever ≥38.3°C, generalized rash ≥3 days, plus cough, coryza, or conjunctivitis, and confirming with serum measles IgM antibody testing collected during the first clinical encounter 1, 2
A clinical case of measles requires all of the following: generalized rash lasting ≥3 days, temperature ≥38.3°C, and at least one of: cough, coryza, or conjunctivitis 1, 3, 4
The primary diagnostic test is serum measles-specific IgM antibody using direct-capture IgM EIA method, which is most sensitive and specific when collected at the time of rash onset 1, 2

Collect blood during the first clinical encounter with suspected measles, and if negative within the first 72 hours, obtain a second specimen ≥72 hours after rash onset 2, 5
IgM may not be detectable in the first 72 hours after rash onset with some assays, and peaks approximately 10 days after rash onset 5
Seropositivity rate is 92-100% when collected 6-14 days after symptom onset 2

A suspected case is any febrile illness accompanied by rash 1, 3
A probable case meets the clinical case definition, is not epidemiologically linked to a confirmed case, and has not been serologically/virologically tested or has noncontributory results 1, 6
A confirmed case meets laboratory criteria or meets the clinical case definition and is epidemiologically linked to a confirmed case 1, 4

The World Health Organization recommends vitamin A supplementation for all children with clinical measles, with dosages of 200,000 IU orally on day 1 for children ≥12 months, and 100,000 IU orally on day 1 for children <12 months 5
Treatment of complications includes bacterial superinfections with appropriate antibiotics, diarrhea with oral rehydration therapy, and acute lower respiratory infections with standard antibiotic treatment 5

Immediate reporting of suspected and known cases to local or state health department is mandatory, and one confirmed case is an urgent public health situation requiring rapid investigation 1, 4, 2
Outbreak control measures include vaccinating or excluding susceptible persons from outbreak settings, and excluding persons exempted from vaccination until 21 days after rash onset in last case 5, 7, 8