Definition

Measles is a highly contagious viral infection. It causes fever, cough, and a characteristic rash. Once a common childhood illness, it is now seen far less often in the United States, due to the widespread use of the measles vaccine [2] , which provides lifelong immunity when given as a series of two shots.

However, vaccination isn’t 100% effective, and there are still individuals who are not vaccinated due to religious and other exemptions. For these reasons, the US continues to see periodic measles outbreaks, most originating among those returning from travel [3] abroad.

Causes

Measles is caused by the measles virus, a paramyxovirus. It is spread by direct contact with nasal or throat secretions of infected people. Less frequently, it can spread by airborne transmission. Measles is communicable from 1-2 days before onset of symptoms, 3-5 days before the rash, and four days after the appearance of the rash.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. It is very unlikely to contract measles if properly immunized as a child with a series of two shots. However, unvaccinated or inadequately vaccinated individuals are at increased risk of measles under the following circumstances:

• Living in crowded and/or unsanitary conditions
• Traveling to less developed countries where measles is common
• Season: winter and spring
• Immunosuppressed state (eg, untreated HIV [4] ), even if previously vaccinated

People born after 1956 who have never been diagnosed with measles or only received an inactivated or killed vaccine prior to 1968 are also at increased risk. (Today's live vaccines are much more effective.)

Symptoms

Symptoms, which usually occur 8-12 days following exposure to the measles virus, include:

• Fever (often high)
• Runny nose
• Red eyes [5]
• Hacking cough
• Sore throat [6]
• Exhaustion
• Very small spots inside the mouth (2-4 days after initial symptoms)
• Raised, itchy rash:
  
  • Starts around the ears, face, and side of neck 3-5 days after initial symptoms appear
  • Generally spreads to the arms, trunk, and legs over the next two days
  • Lasts about 4-6 days

Full recovery, without scarring, generally takes 7-10 days from the onset of the rash.

Diagnosis

The doctor will ask about your symptoms and medical [7] history, and perform a physical exam. Diagnosis of measles is almost always made from the symptoms and the telltale rash. Lab tests are rarely necessary but may be used to confirm the diagnosis in certain situations.

Treatment

Because measles is caused by a virus, it cannot be treated with antibiotics. Effort is focused on relieving the symptoms.

Prevention

Vaccination is the best way to prevent measles. The vaccine contains live viruses that can no longer cause disease.

• Measles vaccine is usually given as part of a combined measles, mumps [11] , and rubella [12] (MMR) vaccination twice: at 12-15 months and again at 4-6 years (or at 11-12 years).
• In some cases, measles vaccine given within three days after exposure to the measles virus can prevent or alleviate the symptoms.
• Immune globulin is often given to nonvaccinated people within six days of exposure to measles. This is especially appropriate for infants, pregnant, or immunocompromised people who live in a house with a measles-contagious person.

Check with your doctor to find out about the exceptions and special circumstances regarding the MMR vaccine. In general, people who should not receive measles vaccination include:

• Those who have had severe allergic reactions to vaccines or vaccine components (such as gelatin or the antibiotic neomycin)
• Women who are pregnant—Women receiving the vaccination should avoid pregnancy for 1-3 months after receiving the vaccination.
• People with an actively weakened immune [13] system
• People with a high fever or severe upper respiratory [14] tract infection—Delay immunization until these symptoms have resolved.

Any unvaccinated person who has not contracted measles should avoid contact with an infected person until all symptoms are gone.