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Key Features

Essentials of Diagnosis

  • Exposure 7–18 days before onset of fever in an unvaccinated patient

  • Prodrome of 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


  • As of October 2017, 120 cases of measles from 15 states are reported to the CDC, surpassing the number of cases reported in 2016

  • Measles were declared eliminated in the United States in 2000

    • Elimination is defined as the absence of endemic measles cases for a period of 12 months or more, in the presence of adequate surveillance (World Health Organization)

  • Since the elimination of measles in 2000 in the United States, outbreaks in the United States occurred predominantly among intentionally unvaccinated children (59–93%)

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 and falsely positive in the presence of rheumatoid factor or with acute rubella, erythrovirus (parvovirus) B19, or HHV-6 infection


  • Administer antipyretics and fluids as ...

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