Measles can live for up to 2 hours in an airspace where the infected person coughed or sneezed. Measles is so contagious that if one person has it up to 90% of the people close to that person who are not immune will become infected. A person is most infectious on the day their rash appears, but infected individuals can spread measles to others from 4 days before through 4 days after their rash onset date. Measles infection is a vaccine-preventable illness: two doses of MMR vaccine are about 97% effective at preventing measles, and even one dose is about 93% effective.

 

Clinical Presentation

The average incubation period for measles is 10–12 days (range: 7–21 days) from the date of the initial exposure until early signs and symptoms appear.

• Early symptoms of measles include a fever (as high as 105°F),malaise, cough, coryza (runny nose), and conjunctivitis (red/watery eyes).
• 2–3 days after symptoms begin, tiny white spots may appear inside the mouth (Koplik spots).
• 3–5 days after symptoms begin, a maculopapular skin rash develops that begins on the face at the hairline and spreads downward to the neck, trunk, arms, legs, and feet. Small raised bumps may also appear on the top of the flat red spots. The spots may become joined together as they spread. As rash appears, an individual’s fever may spike.

When considering measles, healthcare providers should consider the progression of symptoms. Fever and the three “C’s” (cough, coryza, conjunctivitis) almost always appears before the onset of a rash. The rash classically starts on the face and head and spreads down towards the extremities.  Providers should also consider diagnoses including other viral exanthems and drug reactions (e.g., antibiotics, contact dermatitis). Other common causes of febrile rash in children include, parvovirus B-19 (Fifth disease), human herpesvirus 6 (Sixth disease or Roseola), and enteroviruses.

 

Complications

Common complications from measles include otitis media, bronchopneumonia, laryngotracheobronchitis, and diarrhea.

People at high risk for complications include infants and children aged <5 years, adults >20 years, pregnant people, and people with weakened immune systems such as from leukemia and HIV infection.

Even in previously healthy children, measles can cause serious illness requiring hospitalization.

• 1 out of every 1,000 measles cases will develop acute encephalitis, which often results in permanent brain damage.
• 1 to 3 out of every 1,000 children who become infected with measles will die from respiratory and neurologic complications.
• Subacute sclerosing panencephalitis (SSPE) is a rare, but fatal degenerative disease of the central nervous system characterized by:
  • Behavioral and intellectual deterioration.
  • Seizures that generally develop 7 to 10 years after measles infection