Measles is a very contagious (easily spread) illness caused by a virus.

The infection is spread by contact with droplets from the nose, mouth, or throat of an infected person. Sneezing and coughing can put contaminated droplets into the air.

Those who have had an active measles infection or who have been vaccinated against the measles have immunity to the disease. Before widespread vaccination, measles was so common during childhood that most people became sick with the disease by age 20. The number of measles cases dropped over the last several decades to almost none in the U.S. and Canada. However, rates have started to rise again recently.

Some parents do not let their children get vaccinated because of unfounded fears that the MMR vaccine, which protects against measles, mumps, and rubella, can cause autism. Large studies of thousands of children have found no connection between this vaccine and autism. Not vaccinating children can lead to outbreaks of a measles, mumps, and rubella -- all of which are potentially serious diseases of childhood.

Symptoms usually begin 8 - 12 days after you are exposed to the virus. This is called the incubation period.

Symptoms may include:

• Bloodshot eyes
• Cough
• Fever
• Light sensitivity (photophobia)
• Muscle pain
• Rash
  • Usually appears 3 - 5 days after the first signs of being sick
  • May last 4 - 7 days
  • Usually starts on the head and spreads to other areas, moving down the body
  • Rash may appear as flat, discolored areas (macules) and solid, red, raised areas (papules) that later join together
  • Itchy
• Redness and irritation of the eyes (conjunctivitis)
• Runny nose
• Sore throat
• Tiny white spots inside the mouth (Koplik's spots)

• Measles serology
• Viral culture (rarely done)

There is no specific treatment for the measles.

The following may relieve symptoms:

• Acetaminophen (Tylenol)
• Bed rest
• Humidified air

Some children may need vitamin A supplements. Vitamin A reduces the risk of death and complications in children in less developed countries, where children may not be getting enough vitamin A. People who don't get enough vitamin A are more likely to get infections, including measles. It is not clear whether children in more developed countries would benefit from supplements.

Those who do not have complications such as pneumonia do very well.

Complications of measles infection may include:

• Bronchitis
• Encephalitis (about 1 out of 1,000 measles cases)
• Ear infection (otitis media)
• Pneumonia

Call your health care provider if you or your child has symptoms of measles.

Routine immunization is highly effective for preventing measles. People who are not immunized, or who have not received the full immunization are at high risk for catching the disease.

Taking serum immune globulin 6 days after being exposed to the virus can reduce the risk of developing measles, or can make the disease less severe.

Measles. Disease-A-Month. 2007;53.

Mason WH. Measles. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 243.