Measles is best known for causing a full-body rash with red spots. But those spots aren’t the only symptom.

Early measles symptoms can resemble the flu, and infected people are contagious for four days before the tell-tale rash appears, experts say.People with measles are also contagious for four days after the rash begins.

Pre-rash symptoms include fever, fatigue, body aches, a cough, runny nose, and red, watery eyes. People can develop diarrhea, as well. It can take up to 21 days after being exposed to measles to develop symptoms.

Recognizing these early symptoms is important, because people who don’t often inadvertently spread the virus at schools, daycare centers, airports, and other public places. That’s what’s happening now in the United States, more than three decades after measles was declared eliminated. Public health officials reported 2,286 measles cases last year and have already confirmed 1,714 measles cases so far this year.

Exposing the most vulnerable

Because measles makes people feel miserable, they often seek treatment at a doctor’s office, urgent care clinic, or emergency department (ED). But walking into a crowded pediatrician’s office or ED is one of the worst things someone with measles can do, said Andrew Pavia, MD, a pediatric infectious disease specialist in Salt Lake City, Utah, a state that has confirmed 386 cases of measles this year.

Medical facilities are filled with fragile patients—including newborns, older adults, and people with weakened immune systems—who are at high risk of becoming severely ill from measles, Pavia said.

Measles can linger in the air, infecting people up to two hours after a sick person leaves a room. It’s also one of the world’s most contagious viruses, infecting 90% of susceptible people who are exposed to it.

“You always worry about measles transmission in the waiting room,” Pavia said.

A measles patient recently exposed 40 people at Pavia’s hospital to the virus. In response, medical staff quickly searched patients’ medical charts to learn if they were vaccinated. Doctors asked the parents of six newborns—who aren’t usually vaccinated against measles until they’re 1 year old—to return to the hospital for preventive treatment, Pavia said.

“Our experience is not unique,” Pavia said. “This has played out in Texas, South Carolina, Ontario and Alberta [Canada], where the outbreaks spiraled out of control.”

Signs and symptoms to know

With measles becoming more common, experts recommend learning to recognize measles symptoms and taking precautions to protect yourself and others.

The American Academy of Pediatrics recommends children receive two doses of measles vaccine, with the first dose given at 12 months to 15 months of age and the second given when children are four to six years old. During an outbreak, babies can receive their first measles shot at age 6 months but will still need their two regularly scheduled shots for full protection.

Doctors see a lot of people for flu-like illness between fall and early spring, Pavia said. That can make early measles symptoms harder to spot.

By mid-April, as cold and flu season make their exit, “we’re a lot more cautious about fever and cough,” Pavia said. “With flu and RSV [respiratory syncytial virus] almost gone, those two symptoms alone have a much higher likelihood of being measles.

“That’s one reason that people slip through the cracks,” Pavia said. “The other is, quite honestly, people often don’t start out by telling you that they were exposed.”

One of the unique symptoms of measles is an intense sensitivity to light, said Patsy Stinchfield, RN, MS, a pediatric nurse practitioner and the immediate past president of the National Foundation for Infectious Diseases. “Theywant to be in a dark room and will complain to turn the lights off,” said Stinchfield, who oversaw hospital response efforts to three measles epidemics in Minneapolis and St Paul, Minnesota. “Do not bring sick kids out in public, with or without a rash.”

Other early symptoms are tiny, bluish white spots in the mouth known as Koplik spots, which appear one to two daysbefore and after the rash appears (see photo at right). The spots are hard to see, especially by an untrained eye, Stinchfield said.

The tell-tale measles rash includes a mixture of small flat spots mixed with red raised red bumps that typically begins on the forehead and works its way down the body. The rash usually arrives after three to five days of illness. 

What to do if you have flu-like or measles symptoms

“If you have any suspicion that you might have measles, stay at home,” said Ari Brown, MD, a pediatrician in Austin, Texas, and author of Baby 411 and Toddler 411. 

People with measles often become dehydrated and need intravenous (IV) fluids, Stinchfield said. But that doesn’t mean it’s safe to show up at a medical office or clinic unannounced.

“If you are living in an area where measles is occurring, it is always best to call or do a telehealth appointment,” Brown said.

If you have any suspicion that you might have measles, stay at home.

If people need to be seen in person, a telehealth doctor may be able to refer them to a drive-up testing site, Pavia said. Utah has established several of these sites throughout the state.

People who need medical care should call primary care provider or local ED in advance to allow staff to be prepared for their arrival, said Stinchfield. 

Few private medical practices or urgent care clinics have negative air pressure rooms in which to safely isolate people with measles. These practices often opt to send people with measles to the hospital, Stinchfield said. Instead of visiting multiple medical facilities—and exposing staff and patients at each location— it’s often best to call the ED and head straight to the local hospital, whose staff may be better prepared to control airborne viruses. 

If the sick person is a child, Stinchfield suggests calling the closest children’s hospital. “Kids should be taken care of by kid experts,” she said.

Giving medical staff advanced notice allows them to put on N-95 respirators and gowns. ED staff “will tell you exactly where to arrive” to avoid exposing other people, said Stinchfield, who recommends putting on masks before arrival.

If bringing a baby to the hospital with suspected measles, families can drape a blanket over the baby carrier or stroller, Stinchfield added. Hospital staff may meet patients outside and usher them directly to an isolation room to avoid exposing people in the waiting room.

Treating measles: no magic cure

There are no specific treatments for measles, Pavia said. Although doctors can prescribe anti-viral medications for the flu, COVID-19, and HIV, there are no such treatments for the measles virus.

Instead, doctors still treat measles the way they did 50 years ago—by providing “supportive care,” such as IV fluids. 

Although a doctor may prescribe vitamin A for hospitalized children with measles to help them recover, vitamins do not prevent measles. Stinchfield said parents should not give children vitamin A without a doctor’s prescription, because high levels can cause serious liver damage.

Likewise, cod liver oil, which is high in vitamin A and vitamin D, has no proven treatment effect for measles, contrary to recent claims. Antibiotics are not recommended for measles patients unless they have an additional bacterial infection. Antibiotics treat infections caused by bacteria, but are useless against the measles virus.

How to prevent getting measles

Vaccination is the best way to prevent measles. Most unvaccinated people who come into contact with the measles virus can avoid infection by receiving a measles-mumps-rubella (MMR) vaccine within 72 hours, Pavia said. 

“After that, you are protected and don’t need to quarantine,” Pavia said.

But because the MMR vaccine contains a live virus, it’s not recommended for babies under 6 moths of age, pregnant women, or people who are immune-compromised, Pavia noted. Instead, they can receive immune globulin, a sterile solution containing antibodies from human blood, within six days of measles exposure. Babies under one year old can receive an injection, while pregnant or immune-compromised people can receive it intravenously. People who receive immune globulin still need to quarantine for 21 days.

“People may wonder why we can’t just give immune globulin to everyone who is exposed,” Pavia said. “The reason is simple. A healthy 6-month-old will need … one to four uncomfortable injections.”

An adult woman would need a large amount of immune globulin injected into the muscle “which really can’t be practically done,” Pavia said.

Immune globulin “is very expensive, requires admission to a hospital or infusion center, and can have significant side effects,” Pavia said. 

Vaccinating people before they are exposed is safer and more effective.

Unvaccinated people who don’t receive preventive treatment need to quarantine for 21 days, Pavia said. “They have a pretty high likelihood of developing disease, and we don’t want them in classroom or at work when they develop disease, spreading it further.”

In Utah, family doctors and obstetricians are now asking women of childbearing age if they have been vaccinated, Pavia said. If not, they can get be vaccinated before becoming pregnant or after delivering a baby.

Of note: There is no “natural” way to prevent measles, in spite of what people say. 

When to seek medical care

About 20% of unvaccinated people with measles are hospitalized owing to complications such as pneumonia or brain swelling. For every 1,000 people with measles, one to three people die.

If someone with measles gets rapidly worse, they should go to the ED. People with measles also should go to the ED if they develop other serious complications, including:

• Trouble breathing (or breathing faster than normal)
• Pain when breathing or coughing
• Dehydration (dry nose and mouth, urinating less, crying without making tears)
• Fever or headache that will not stop
• Confusion, decreased alertness, or severe weakness
• Blue color around the mouth, low energy, or difficulty feeding (for young children).