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For further information, see CMDT Part 32-02: Major Vaccine-Preventable Viral Infections

Key Features

Essentials of Diagnosis

  • Onset of prodrome 7–18 days after exposure in an unvaccinated patient

  • Prodrome:

    • Fever

    • Coryza

    • Cough

    • Conjunctivitis

    • Malaise

    • Irritability

    • Photophobia

    • Koplik spots

  • Rash

    • Brick red, irregular, maculopapular

    • Appears 3–4 days after onset of prodrome

    • Begins on the face and proceeds "downward and outward," affecting the palms and soles last

  • Leukopenia

General Considerations

  • Transmitted by inhalation of infective droplets

  • Highly contagious

  • Communicability is greatest during the preeruptive and catarrhal stages, continuing for 4 days after the appearance of rash

  • Illness confers permanent immunity


  • Between January 1 and October 1, 2019, a total of 1249 measles cases and 22 measles outbreaks were reported in 31 states of the United States

  • The WHO previously considered measles eradicated in most countries worldwide including the Americas

  • However, many countries now have ongoing measles outbreaks, including

    • The Democratic Republic of the Congo

    • Ethiopia

    • Georgia

    • Kazakhstan

    • Kyrgyzstan

    • Madagascar

    • Myanmar

    • Philippines

    • Sudan

    • Thailand

    • Ukraine

  • During 2019, measles outbreaks have also occurred in countries with high vaccination coverage, including

    • The United States

    • Israel

    • Thailand

    • Tunisia

    • Many European countries

  • Intentional undervaccination continues to undermine measles elimination programs

Clinical Findings

Symptoms and Signs

  • Prodromal phase

    • Fever

    • Malaise may be marked

    • Coryza (nasal obstruction, sneezing, and sore throat)

    • Persistent and nonproductive cough

    • Conjunctivitis manifests as redness, swelling, photophobia, and discharge

  • These symptoms intensify over 2–4 days before onset of the rash and peak on the first day of the rash

  • Characteristic measles rash appears on the face and behind the ears

    • Initial lesions are pinhead-sized papules that coalesce to form a brick red, irregular, blotchy maculopapular rash

    • Spreads to the trunk and extremities, including the palms and soles

    • Lasts for 3–7 days and fades in the same manner it appeared

  • Koplik spots

    • Small, irregular, and red with whitish center on the mucous membranes

    • Appear about 2 days before the rash and last 1–4 days as tiny "table salt crystals" on the palatal or buccal mucosa opposite the molars or on vaginal membranes

  • Other findings

    • Pharyngeal erythema

    • Tonsillar yellowish exudate

    • Coating of the tongue in the center with a red tip and margins

    • Moderate generalized lymphadenopathy

    • Splenomegaly

Differential Diagnosis

  • Kawasaki disease

  • May be mistaken for other exanthematous infections


  • Koplik spots are pathognomonic

  • Leukopenia usually present unless secondary bacterial complications exist

  • Thrombocytopenia is common

  • Proteinuria is often observed

  • Real-time reverse transcriptase-polymerase chain reaction (RT-PCR), available from the CDC and some public health laboratories, can help establish a diagnosis

  • Detection of IgM measles antibodies with ELISA or fourfold rise in measles antibody titer is diagnostic

  • IgM assays can be falsely negative the first few days of infection ...

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