Measles

Summary

Measles is a highly contagious viral disease characterized by a red skin rash. It is also called rubeola.

Measles was once a common infection in most children's lives. A vaccine for measles has been widely available since 1963 and has greatly reduced the incidence of the disease. However, there are still millions of measles cases reported worldwide each year.

People who have not been vaccinated or have not had the disease are extremely likely to contract measles if they come into contact with it. Most cases that occur in the United States today are a result of unvaccinated people traveling internationally or among groups of people who have not been vaccinated and are exposed to the disease.

Measles is transmitted easily when infected people cough or sneeze and other people breathe infected air or touch infected surfaces. The first symptom usually experienced is a high fever, followed by a cough, runny nose and conjunctivitis (pink eye). The rash that is characteristic of measles develops in the face and upper neck and then spreads to lower parts of the body, including the hands and feet.

Although otherwise healthy people who develop measles may become quite ill, most patients fully recover. However, patients can develop complications that can be serious and potentially fatal. These include ear infections, pneumonia and inflammation of the brain (encephalitis).

Diagnosis is usually made during a physical examination. Measles can usually be diagnosed without medical tests, but sometimes a blood test is performed to verify a diagnosis.

There is no cure for the virus that causes measles, but symptoms can be treated with bed rest, fluids, over–the–counter pain relievers and other measures.

The best way to prevent measles is to receive the MMR (measles, mumps and rubella) vaccination. Children usually receive their first dose of the vaccination after the first year of life (between 12 to 15 months) and a second dose before they begin kindergarten (usually at age 5).

About measles

Measles is a highly contagious respiratory disease caused by a virus that results in a red, blotchy skin rash.

Also called rubeola, measles occurs most often in the late winter and spring. Once the virus enters the body, it grows on the cells that line the back of the throat and lungs. The infection then spreads throughout the body. It usually begins with a fever that lasts for a few days, followed by a cough, runny nose and conjunctivitis (pink eye). A rash starts on the face and upper neck and then spreads to other parts of the body.

When an infected person sneezes or coughs, droplets spray into the air and can land on surfaces or reach other people's noses and throats when they breathe. The virus can remain active for up to two hours on a surface and can be transmitted during this timeframe if a person touches it.

Though the symptoms experienced by people with measles are unpleasant, most people (particularly those living in the United States and other industrialized countries) recover fully. However, the complications of the illness can be serious and potentially fatal. Between 6 and 20 percent of people with measles develop an ear infection, diarrhea or pneumonia. One out of every 1,000 people with measles develops inflammation of the brain (encephalitis) and about one out of every 1,000 people with measles dies, according to the U.S. Centers for Disease Control and Prevention (CDC).

Other complications may include:

• Bronchitis, laryngitis or croup. Measles may lead to laryngitis (inflammation of the voice box), bronchitis (inflammation of the inner walls that line the main air passages to the lungs) or croup (a disease of infants and young children marked by harsh coughing and fever).
  
  
• Pregnancy problems. Measles can cause miscarriage (spontaneous termination of pregnancy), premature labor or babies with low birth weight.
  
  
• Low platelet count (thrombocytopenia). Measles may lead to a decrease in platelets, the type of blood cells needed for blood clotting.

Before a measles vaccine was first licensed in the United States in 1963, measles was considered a part of childhood and almost everyone developed the disease. Although the vaccine has reduced the number of measles cases in the United States by greater than 99 percent, it is still considered a serious health problem, according to the CDC.

Between 1989 and 1991, there was a measles epidemic in the United States among children who did not receive the vaccine or received only one dose of it. The vaccine is not as widely available in many developing countries and there are still millions of measles cases reported worldwide each year. Although unvaccinated people are unlikely to come into contact with the measles virus in the United States, international travel to other areas may expose more people to the virus.

In recent years, the number of measles cases in the United States has been small (fewer than 50 cases). These usually involve high school or college students who have not been vaccinated or have received only a single dose of the vaccine, according to the CDC. Since 1993, the largest outbreaks of measles have occurred among groups that refuse to be vaccinated.

Measles should not be confused with German measles (rubella), another formerly common disease caused by a different virus. Rubella usually produces much milder symptoms in children, although it can be more severe in teenagers and adults. Vaccines for both diseases are part of the measles, mumps and rubella (MMR) vaccine usually given to children.

Risk factors and causes of measles

Measles is caused by a paramyxovirus that resides in the mucus in the nose and throat of an infected person. It can be transmitted from four days prior to development of a skin rash until four days after the onset of the rash.

Measles is extremely contagious. According to the U.S. Centers for Disease Control and Prevention (CDC), up to 90 percent of people without measles immunity who come into contact with a person with measles will develop the disease.

Measles is rare in the United States because most people receive vaccinations at a young age. However, exposure to an infected person may result in measles in those who have not received vaccinations or have received only a partial vaccination and have not developed sufficient immunity to the disease. Measles is more common in other countries, where the vaccination may not be available or may not be common.  

People who have had measles develop a resistance against it and will not get measles again. People born or living in the United States before 1957 are also likely immune from measles because they probably lived through a measles epidemic and were exposed to the disease. After exposure, the immune system develops resistance even if symptoms are not experienced.

Signs and symptoms of measles

Symptoms typically appear between 10 and 12 days after exposure to the measles virus. Infected people will first develop a fever that may peak as high as 103 to 105 degrees Fahrenheit (39.4 to 40.6 degrees Celsius) and last for two to four days. The fever is usually followed by a cough, runny nose and conjunctivitis (pink eye).

The characteristic skin rash of measles typically appears about 14 days after exposure to the virus (or several days after the high fever) and lasts for five to six days. The rash may appear as macules (flat, discolored areas of the skin) or papules (solid, red, elevated areas of the skin). The rash may also itch. It begins at the hairline and then spreads to the face and upper neck. Over the next three days, the rash spreads down the body and to the extremities, eventually reaching the hands and feet. The rash fades after about a week in the same sequence that it appeared.

Other measles symptoms that may appear include:

• Koplik's spots (tiny red spots with bluish–white centers on the inner lining of the cheek)
• Sore throat
• Muscle pain
• Sensitivity to light (photophobia)

Diagnosis and treatment of measles

A physician should be contacted immediately if measles is suspected, particularly in a young child. A physician can usually diagnose measles just by looking at the rash during a physical examination, and obtaining a medical history.

Although physicians can usually identify measles, a blood test may be performed to confirm the diagnosis because measles is rare in the United States. A blood sample is drawn and sent to a laboratory, where it will be studied under a microscope to determine whether the measles virus is present.

Because measles is highly contagious, patients should be isolated from others, particularly during the four days before and four days after development of the rash (when the virus is most communicable). It may be necessary to remove people living in the same house as a patient with measles (such as siblings) to avoid spreading the disease.

Treatment for measles focuses on alleviating the symptoms. The following measures may relieve the severity of some symptoms:

• Bed rest may make patients more comfortable.
  
  
• Sponge baths with lukewarm water to the face and upper body for fevers higher than 100.5 degrees Fahrenheit (38 degrees Celsius) can provide relief.
  
  
• Drinking fluids helps avoid dehydration.
  
  
• Over-the-counter medicines may relieve or quiet coughing. Humidifying the air with a cool mist vaporizer or pans of water in a room may also relieve coughing.
  
  
• Analgesics help reduce pain and fever. Aspirin should not be given to children and teenagers because it has been linked to Reye syndrome, a potentially fatal condition that impacts the brain and other organs.
  
  
• Over-the-counter lotions are available to relieve itching.
  
  
• Nails may be trimmed or gloves may be worn if a child is scratching skin excessively.

Patients who develop bacterial infections, such as pneumonia or ear infections, may be treated with antibiotics (medications that fight bacterial infections).

In developing countries, where vitamin deficiencies are common, physicians have administered vitamin A supplements to reduce the severity of measles symptoms and complications, such as blindness. Although vitamin A deficiency is less common in the United States, physicians give supplements of vitamin A to children ages six months to two years who are hospitalized with measles.

Prevention methods for measles

The best way to prevent measles is to receive an MMR (measles, mumps and rubella) vaccination. This combined form was first licensed in 1971 and contains the most effective forms of each vaccine.

Almost 95 percent of those who receive a single dose of the vaccine will develop immunity to all three viruses. A second dose will provide immunity to most of the 5 percent of people who did not respond to the first dose, according to the U.S. Centers for Disease Control and Prevention (CDC).

Most people experience no side effects from the vaccination. Some people develop a fever between five and 12 days after the vaccination. Others develop a mild rash. It was once commonly believed that people who are allergic to eggs cannot receive vaccines grown in chick embryos, such as the measles vaccine. However, this is not true.

People who should not receive an MMR vaccine include pregnant women and those with immune systems that are suppressed from prescription immunosuppressant drugs or conditions such as cancer or human immunodeficiency virus (HIV). Infants who have not received the vaccine may be given it within 72 hours of exposure to the measles virus to provide protection against the disease. Pregnant women, infants and people with weakened immune systems who have been exposed to the virus may receive an injection of antibodies (proteins that fight bacteria and viruses) called hyperimmune gamma globulin. When administered within six days of exposure, the antibodies may prevent development of measles or lessen the severity of symptoms.

Under CDC guidelines, those who should receive a vaccination include:

• Children. Because mothers pass immunity to newborns, babies are usually immune from measles during the first year of life. Infants should receive their first vaccine shot after their first birthday (ages 12 to 15 months) and receive a second dose before they begin kindergarten (usually at age five).
  
  
• Teenagers. Before they enter middle school, high school or college, students should have received both doses of the MMR vaccine. Although rare, outbreaks continue to occur in school settings because of large concentrations of susceptible people. Many states require students to show evidence of vaccinations before entering some school environments.
  
  
• Adults born after 1957 should receive at least one dose of the measles vaccine unless they have already had measles or are immune. This vaccine can also be administered as an MMR (measles, mumps, rubella) or MR (measles, rubella) vaccine. Those at increased risk of measles, such as college students, international travelers and health workers, should receive two doses, as long as they are administered no less than one month apart. Pregnant women should not receive the MMR vaccine. Pregnancy should be avoided for one month after measles vaccination and three months following MMR vaccination.
  
  
• Travelers. Because measles is more common in other countries, particularly developing countries, travelers are at a greater risk of getting measles. Travelers who are not immune to measles should receive two doses of the MMR vaccine.

In recent years, some parents have refused to have their children vaccinated because of fears that the MMR vaccine can cause autism, a lifelong developmental disability that affects brain function. The number of children diagnosed with autism has increased significantly in recent years, during the same time that the number of recommended childhood vaccines has increased.

The National Academy of Sciences Institute of Medicine reviewed safety concerns of the MMR vaccine at the request of the CDC and the National Institutes of Health. Their report concluded that the increase in autism cases cannot be linked to the MMR vaccine, although there is insufficient information to exclude the vaccine as a cause in rare circumstances. The CDC has not changed its recommendations that children should receive the MMR vaccine to prevent measles.

Questions for your doctor

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following measles–related questions:

1. If measles has been virtually eliminated in the United States, why should I (or my child) get vaccinated?
   
   
2. My child has a rash. Are there other diseases that he may have besides measles?
   
   
3. How can I distinguish measles from other childhood diseases?
   
   
4. I was born before 1963 and never received a measles vaccination. Should I be vaccinated now?
   
   
5. When should my child receive the first measles vaccine shot?
   
   
6. Is getting the measles vaccination mandatory for my child?
   
   
7. I travel frequently to other countries. Should I receive a measles vaccination?
   
   
8. My child has measles. Should my other children be removed from the house during the course of the illness?