14-12: Measles

Clinical Summary

Measles presents as an acute febrile illness with a 3- to 4-day prodromal period characterized initially by fever, malaise, and anorexia, followed closely by conjunctivitis, coryza, and cough. Koplik spots, the pathognomonic enanthem of measles, appear as 1- to 3-mm red papules with gray-white centers on the buccal mucosa. They usually present transiently approximately 48 hours before the development of the characteristic erythematous blanching maculopapular rash. The rash appears on day 3 or 4 after the onset of fever as dark red to purple macules and papules on the forehead, around the hairline, and behind the earlobes, subsequently spreading in a cephalocaudad progression, often becoming confluent. The lesions tend to fade in the same order that they appear.

Most cases recover without complications; others may develop otitis media, croup, pneumonia, encephalitis, myocarditis/pericarditis, keratitis, and rarely subacute sclerosing panencephalitis, a very late complication. The differential diagnosis of the characteristic rash is vast and includes exanthem subitum; rubella; infections caused by echovirus, coxsackievirus, and adenoviruses; toxoplasmosis; infectious mononucleosis; scarlet fever; Kawasaki disease; drug reactions; Rocky Mountain spotted fever; and meningococcemia.

Management and Disposition

Supportive therapy includes bed rest, antipyretics, and adequate fluid intake. Complications should be treated accordingly. Currently available antivirals are not effective. The World Health Organization recommends oral vitamin A once per day for 2 days in vitamin A–deficient areas to reduce morbidity and mortality. Postexposure prophylaxis (PEP) includes administration of the measles-mumps-rubella (MMR) vaccine within 72 hours of exposure to a patient with active measles. Passive immunization with IV immune globulin (IVIG) is effective for prevention and attenuation of measles if given within 6 days of the initial exposure especially in pregnant women and the immunocompromised. During outbreaks, MMR vaccine can be given to infants younger than 12 months. However, such infants require an additional two doses of MMR at the recommended ages after their 1st birthday.

Pearls

1. Measles outbreaks are being seen in developing countries with decreased vaccination rates.

2. MMR vaccine is preferable to IVIG as PEP.

3. Morbilliform means measles-like.

4. Maintain airborne transmission precautions for suspected and confirmed measles cases. Healthcare providers should use appropriate respiratory protection (N95 respirator or other respirator with similar effectiveness).