Diseases & Conditions


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Measles


Measles (rubeola, 9-day measles) is a highly contagious viral infection that produces various symptoms and a characteristic rash.

Children become infected with measles by breathing in small airborne droplets of moisture coughed out by an infected person or by touching items contaminated by such droplets. Measles is contagious from several days before until several days after the rash appears.

Before vaccination became widely available, measles epidemics occurred every 2 or 3 years, particularly in preschool-aged and school-aged children. Small, localized outbreaks occurred during intervening years. Although measles is still common in other countries, only about 100 to 300 people a year in the United States develop measles. A woman who has had measles or has been vaccinated passes immunity (in the form of antibodies) to her child. This immunity lasts for most of the first year of life. Thereafter, however, susceptibility to measles is high unless vaccination is given. A person who has had measles develops immunity and cannot contract it again.

Symptoms and Diagnosis

The symptoms of measles begin about 7 to 14 days after infection. The infected child first develops a fever, runny nose, hacking cough, and red eyes. Sometimes the eyes are sensitive to bright light. Tiny white spots (Koplik's spots) appear inside the mouth 2 to 4 days later, and then the child develops a sore throat.

A mildly itchy rash appears 3 to 5 days after the start of symptoms. The rash begins in front of and below the ears and on the side of the neck as irregular, flat, red areas that soon become raised. The rash spreads within 1 to 2 days to the trunk, arms, palms, legs, and soles and begins to fade on the face.

At the peak of the illness, the child feels very sick and develops eye inflammation (conjunctivitis), the rash is extensive, and the temperature may exceed 104° F (40° C). In 3 to 5 days, the temperature falls, the child begins to feel better, and any remaining rash quickly fades. The diagnosis is based on the typical symptoms and characteristic rash.

Brain infection (encephalitis) occurs in about 1 out of 1,000 to 2,000 children with measles. If encephalitis occurs, it often starts with a high fever, headache, seizures, and coma, usually 2 days to 1 week after the rash appears. The illness may be brief, with recovery in about 1 week, or it may be prolonged, resulting in brain damage or death.

Secondary bacterial infections, such as pneumonia (especially in infants) or a middle ear infection (otitis media), occur fairly often. Rarely, blood platelet levels become so low that the child bruises and bleeds.

Prognosis

In healthy, well-nourished children, measles is rarely serious. However, secondary bacterial infections, particularly pneumonia, can occasionally be fatal. In rare cases, subacute sclerosing panencephalitis—a serious complication of measles—occurs months to years later, resulting in brain damage (see Viral Infections: Subacute Sclerosing Panencephalitis (SSPE) ).

Prevention

Measles vaccine, one of the routine immunizations of childhood, is given between 12 and 15 months of age (see Vaccinating Infants and Children ) but can be given to children as young as 6 months during a measles outbreak. Children (and adults) who are exposed to measles and do not have immunity may be protected by vaccination within 3 days of exposure. Pregnant women and infants younger than 1 year should not receive the vaccine in a non-outbreak situation and instead are given measles immune serum globulin for protection.

Treatment

There is no specific treatment for measles. Some doctors in the United States give vitamin A to children aged 6 months to 2 years who are hospitalized with measles, because vitamin A has reduced the number of deaths from measles in countries where vitamin A deficiency is common. Children with measles are kept warm and comfortable. Acetaminophen Some Trade Names TYLENOL or ibuprofen Some Trade Names ADVIL MOTRIN NUPRIN may be given to reduce fever. If a secondary bacterial infection develops, an antibiotic is given.

Last full review/revision May 2007 by Mary T. Caserta, MD

Source: The Merck Manual Home Edition