Measles: Symptoms, Rash, Treatment & Vaccine Protection

What Is Measles and How Dangerous Is It?

Measles (rubeola) is a highly contagious viral disease caused by the measles virus that spreads through respiratory droplets. It causes high fever, characteristic red rash, and can lead to life-threatening complications including pneumonia and brain inflammation. Before vaccination, measles killed 2-3 million people annually worldwide.

Measles is caused by a virus belonging to the paramyxovirus family. The disease is spread through the air when an infected person coughs or sneezes, releasing tiny droplets that can remain infectious in the air or on surfaces for up to two hours. The measles virus is remarkably contagious – one of the most transmissible human pathogens known to science. If one person in a room has measles, approximately 90% of susceptible (unvaccinated and previously uninfected) people nearby will become infected.

The global impact of measles has been dramatic throughout human history. Before the widespread use of measles vaccines beginning in the 1960s, the disease caused an estimated 2.6 million deaths each year worldwide. Even with current vaccination efforts, measles killed approximately 140,000 people in 2018, with the vast majority being children under 5 years of age in developing countries. In regions with high vaccination coverage, measles has become rare, but outbreaks continue to occur, particularly in communities with low vaccination rates.

What makes measles particularly concerning is not just the acute illness itself, but the range of serious complications that can develop. The disease temporarily weakens the immune system, leaving patients vulnerable to secondary bacterial infections for weeks or even months after recovery. This phenomenon, known as "immune amnesia," can erase the body's memory of previously encountered pathogens, potentially undoing years of acquired immunity.

Why is measles so contagious?

The measles virus has several characteristics that make it extraordinarily transmissible. First, the virus can remain airborne and viable for up to two hours after an infected person has left a room. Second, the virus can be transmitted before symptoms appear, making it difficult to avoid exposure. Third, the amount of virus shed by infected individuals is extremely high during the contagious period. Scientists use a measure called the basic reproduction number (R₀) to describe how contagious a disease is – measles has an R₀ of 12-18, meaning one infected person can transmit the virus to 12-18 others in a fully susceptible population. For comparison, influenza has an R₀ of about 2-3.

Who is most at risk?

While measles can infect anyone who isn't immune, certain groups face higher risks of infection and complications. Unvaccinated children under 5 years old are particularly vulnerable, as their immune systems are still developing. Pregnant women who contract measles face increased risks of premature labor, low birth weight, and maternal death. Individuals with compromised immune systems – including those with HIV/AIDS, those undergoing chemotherapy, or those taking immunosuppressive medications – are at high risk of severe, potentially fatal measles infections.

What Are the Symptoms of Measles?

Measles symptoms begin 10-14 days after exposure with high fever (often exceeding 104°F/40°C), dry cough, runny nose, and red, watery eyes sensitive to light. A characteristic red, blotchy rash develops 3-5 days later, typically starting on the face and spreading downward across the body.

The symptoms of measles develop in a predictable pattern that helps distinguish it from other viral illnesses. Understanding this progression is important for early recognition and appropriate management of the disease. The illness typically unfolds in two distinct phases: the prodromal (pre-rash) phase and the exanthematous (rash) phase.

Prodromal phase (days 1-4)

The prodromal phase begins approximately 10 to 14 days after initial exposure to the virus. During this phase, patients experience what may initially seem like a severe cold or flu. The hallmark symptoms include a high fever that often spikes above 104°F (40°C), which is typically higher than fevers seen with common respiratory infections. The cough associated with measles is characteristically dry and persistent, often worsening as the illness progresses.

Coryza (runny nose) is another prominent feature, with copious clear nasal discharge that contributes to the general misery of the illness. Perhaps most distinctive is the conjunctivitis – the eyes become red, watery, and extremely sensitive to light (photophobia). This combination of symptoms is sometimes referred to as the "three Cs" of measles: cough, coryza, and conjunctivitis.

About 2-3 days before the main rash appears, small white spots may develop inside the mouth, particularly on the inner cheeks opposite the molars. These are called Koplik spots and are considered pathognomonic (uniquely characteristic) of measles. They appear as tiny white or bluish-white spots on a red background and typically disappear as the skin rash develops.

Exanthematous phase (rash)

The characteristic measles rash typically appears 3-5 days after the onset of symptoms. The rash is maculopapular, meaning it consists of both flat discolored areas (macules) and small raised bumps (papules). It characteristically begins on the face, often at the hairline and behind the ears, before spreading downward to the neck, trunk, arms, and legs over the course of 3-4 days.

The appearance of the rash can vary somewhat depending on skin tone. On lighter skin, the rash typically appears red and may darken to a brownish color as it ages. On darker skin, the rash may appear darker from the onset and can sometimes be more difficult to see, though it often remains visible as slightly raised bumps that can be felt when touching the skin.

As the rash spreads, individual spots often merge together, creating larger patches of discoloration. The fever usually remains high during the early rash phase but typically begins to subside 3-4 days after the rash appears. The rash fades in the same order it appeared – starting from the face and moving downward – often leaving a temporary brownish discoloration and fine scaling of the skin.

When Should You Seek Medical Care for Measles?

Contact a healthcare provider immediately if you suspect measles – call before visiting to prevent spreading the infection. Seek emergency care for difficulty breathing, severe drowsiness or confusion, seizures, or inability to drink fluids. These may indicate serious complications requiring urgent treatment.

If you believe you or your child may have measles, it is essential to contact a healthcare provider promptly. However, due to the highly contagious nature of the disease, it is critically important that you call ahead before visiting any healthcare facility. Walking into a doctor's office or emergency room without warning could expose dozens of vulnerable individuals – including pregnant women, young infants, and immunocompromised patients – to the virus.

When you call, describe the symptoms you're experiencing, including the fever, cough, eye symptoms, and whether a rash has developed. The healthcare provider will give you instructions on how to be evaluated safely, which may include using a separate entrance, being seen at a specific time, or being directed to a particular facility equipped to handle infectious diseases.

Contact a healthcare provider if:

• You suspect measles based on symptoms (fever, cough, runny nose, red eyes, rash)
• You have been in contact with someone diagnosed with measles
• You are unsure about your vaccination status after potential exposure
• You are pregnant and may have been exposed to measles
• Your child has a high fever and you're concerned about measles

How Does Measles Spread?

Measles spreads through respiratory droplets when an infected person coughs or sneezes. The virus can remain infectious in the air for up to 2 hours after the infected person has left. Infected individuals are contagious from 4 days before to 4 days after the rash appears.

Understanding how measles spreads is crucial for prevention. The measles virus is transmitted primarily through respiratory droplets produced when an infected person coughs, sneezes, or even talks. These droplets can travel through the air and be inhaled by others nearby. What makes measles particularly dangerous is that the virus can also remain suspended in the air as tiny aerosol particles that linger long after the infected person has left the area.

Research has shown that the measles virus can remain viable and infectious in an enclosed space for up to two hours. This means that you can contract measles simply by entering a room where an infected person was present earlier, even if that person is no longer there. The virus can also settle on surfaces, where it may remain infectious for several hours, though direct respiratory transmission is the primary route of infection.

The contagious period for measles extends from approximately 4 days before the rash appears until 4 days after. This is particularly problematic because individuals become contagious during the prodromal phase, before the characteristic rash makes the diagnosis obvious. During this time, they may believe they simply have a cold or flu and continue their normal activities, unknowingly exposing many others to the virus.

Contact tracing and outbreak control

Because measles is so contagious and can have serious consequences, public health authorities take confirmed cases very seriously. When a case of measles is confirmed, contact tracing begins to identify everyone who may have been exposed during the infectious period. This typically includes household members, classmates, healthcare workers, and anyone who shared enclosed spaces with the infected individual during the contagious period.

Those identified as exposed contacts who are susceptible (unvaccinated or with uncertain immunity) may be offered post-exposure prophylaxis, which can include vaccination within 72 hours of exposure or immunoglobulin within 6 days of exposure. These interventions can prevent disease or reduce its severity if administered promptly.

How Is Measles Diagnosed?

Measles is initially diagnosed clinically based on the characteristic combination of high fever, cough, conjunctivitis, and rash. Laboratory confirmation is obtained through blood tests detecting measles-specific IgM antibodies or PCR testing that identifies viral genetic material from respiratory samples.

The diagnosis of measles often begins with clinical suspicion based on the patient's symptoms and potential exposure history. An experienced healthcare provider may strongly suspect measles when seeing the classic presentation: a febrile patient with the "three Cs" (cough, coryza, conjunctivitis) followed by a characteristic maculopapular rash that spreads from head to toe. The presence of Koplik spots, while not always visible by the time the rash appears, is considered diagnostic when present.

However, because measles has become uncommon in countries with high vaccination rates, many healthcare providers may have limited experience with the disease. Laboratory confirmation is therefore important not only for individual patient management but also for public health surveillance and outbreak response.

Laboratory tests for measles

The most common laboratory test for measles is serological testing for measles-specific IgM antibodies in the blood. These antibodies typically become detectable at the time the rash appears and remain elevated for several weeks. A positive IgM test in a patient with compatible symptoms confirms the diagnosis. However, the test may be falsely negative if performed too early in the illness or in patients who have previously been vaccinated.

Reverse transcription polymerase chain reaction (RT-PCR) testing can detect measles virus RNA from respiratory specimens (throat swabs, nasopharyngeal swabs) or urine. This test is highly sensitive and specific, and can detect the virus even before antibodies develop. PCR testing is particularly valuable for confirming cases in vaccinated individuals, where antibody responses may be modified, and for genotyping the virus to trace the source of outbreaks.

How Is Measles Treated?

There is no specific antiviral treatment for measles. Treatment focuses on supportive care including rest, fluids, fever-reducing medications, and managing symptoms. Vitamin A supplementation is recommended by WHO for all children with measles. Complications like pneumonia may require antibiotics and hospitalization.

Unlike some viral infections for which specific antiviral medications exist, there is no direct treatment that can kill the measles virus or shorten the duration of infection. The primary approach to measles management is supportive care – measures that help the body fight the infection and maintain comfort while the immune system clears the virus naturally.

Rest is fundamental to recovery from measles. Patients should be encouraged to rest in a comfortable environment, ideally a cool, dimly lit room since the conjunctivitis and photophobia make bright light uncomfortable. Maintaining adequate hydration is crucial, especially given the high fever and potential for reduced oral intake. Fever-reducing medications such as acetaminophen (paracetamol) or ibuprofen can help control fever and relieve discomfort, though aspirin should be avoided in children due to the risk of Reye's syndrome.

Vitamin A supplementation

The World Health Organization recommends vitamin A supplementation for all children diagnosed with measles. This recommendation is based on substantial evidence that vitamin A deficiency increases the risk of severe measles and death, and that supplementation can reduce mortality by approximately 50% in populations with high rates of vitamin A deficiency. Even in well-nourished populations, vitamin A stores become depleted during measles infection, and supplementation may help reduce complications.

The WHO recommends two doses of vitamin A, given 24 hours apart: 200,000 IU for children aged 12 months and older, 100,000 IU for infants 6-11 months, and 50,000 IU for infants under 6 months. Higher doses may be given to children with clinical signs of vitamin A deficiency.

Treatment of complications

When complications develop, additional treatments become necessary. Bacterial pneumonia, the most common serious complication, requires antibiotic therapy. The choice of antibiotic depends on local resistance patterns and the severity of infection, but typically covers common respiratory pathogens such as Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus.

Patients with severe measles or complications may require hospitalization for intravenous fluids, oxygen therapy, or intensive care. Encephalitis, while rare, is a particularly serious complication that may require management in an intensive care setting with supportive measures for brain swelling and seizure control.

What Are the Complications of Measles?

Measles complications occur in about 30% of cases and include ear infections, pneumonia (the leading cause of measles deaths), encephalitis (brain inflammation affecting 1 in 1,000 cases), and a rare fatal brain disorder called SSPE that can develop years after infection. Approximately 1-2 per 1,000 cases result in death.

While many people recover from measles without lasting effects, complications are common, occurring in approximately 30% of cases. Some complications are relatively minor, while others can be life-threatening or cause permanent disability. Children under 5 years of age, adults over 20, pregnant women, and immunocompromised individuals face the highest risk of complications.

Common complications

Otitis media (middle ear infection) is one of the most frequent complications, affecting about 1 in 10 children with measles. It occurs when the virus or secondary bacterial infection spreads to the middle ear, causing pain, fever, and sometimes hearing impairment. While usually treatable with antibiotics, repeated ear infections can contribute to hearing loss.

Diarrhea occurs in about 8% of measles cases and can be particularly dangerous in young children, leading to dehydration and electrolyte imbalances. Measles-associated diarrhea can persist for days to weeks and may contribute significantly to malnutrition in children in resource-limited settings.

Serious complications

Pneumonia is the most common cause of death from measles, accounting for approximately 60% of measles-related fatalities. It can result from the measles virus itself (primary viral pneumonia) or from secondary bacterial infection taking advantage of the damaged airways and suppressed immune system. Approximately 1 in 20 children with measles develops pneumonia. Warning signs include rapid or difficult breathing, chest retractions, and inability to drink.

Encephalitis (inflammation of the brain) occurs in approximately 1 in 1,000 measles cases and is one of the most feared complications. It typically develops within days of the rash appearing and presents with headache, high fever, seizures, and altered consciousness. While many patients survive, encephalitis causes permanent brain damage in about 25% of cases and is fatal in about 10-15% of affected individuals.

Subacute sclerosing panencephalitis (SSPE)

Perhaps the most tragic complication of measles is subacute sclerosing panencephalitis (SSPE), a rare but invariably fatal degenerative brain disease that develops 7-10 years after measles infection. SSPE occurs in approximately 1 in 10,000 measles cases, though the risk is higher for those infected before age 2 (approximately 1 in 600).

SSPE begins insidiously with behavioral changes and declining school performance, progressing to dementia, motor dysfunction, and eventually a persistent vegetative state. There is no effective treatment, and death typically occurs within 1-3 years of diagnosis. The existence of SSPE underscores the importance of measles prevention through vaccination.

How Does the Measles Vaccine Work?

The MMR (measles, mumps, rubella) vaccine contains weakened live virus that stimulates immunity without causing disease. One dose provides about 93% protection; two doses provide approximately 97% lifelong protection. Children typically receive the first dose at 12-15 months and the second at 4-6 years.

The measles vaccine is one of the most successful and safe vaccines ever developed. It has prevented an estimated 56 million deaths between 2000 and 2021, making it one of public health's greatest achievements. The vaccine is typically administered as part of the combination MMR (measles, mumps, rubella) vaccine, and in some countries as MMRV which also includes varicella (chickenpox).

The measles vaccine contains a live but weakened (attenuated) form of the measles virus. This weakened virus is capable of replicating in the body just enough to stimulate a robust immune response, including the production of antibodies and memory cells, but not enough to cause measles disease. The immunity produced by vaccination is virtually identical to that produced by natural infection, providing long-lasting, often lifelong protection.

Vaccination schedule

Most countries recommend a two-dose schedule for measles vaccination. The first dose is typically given at 12-15 months of age, when maternal antibodies (which can interfere with vaccine response) have waned but before the child enters environments like daycare or preschool where exposure risk increases. The second dose is usually given at 4-6 years of age, before school entry.

The reason for the two-dose schedule is to ensure maximum protection across the population. While a single dose of measles vaccine is about 93% effective, approximately 7% of recipients do not respond adequately to the first dose for various reasons. The second dose provides an opportunity for these primary vaccine failures to develop immunity, raising the overall effectiveness to approximately 97%.

Safety of the measles vaccine

The measles vaccine has an excellent safety profile supported by decades of use in billions of people worldwide. The most common side effects are minor: soreness at the injection site, mild fever, and occasionally a faint rash appearing 1-2 weeks after vaccination. These reactions indicate that the immune system is responding to the vaccine and are not cause for concern.

Serious adverse events are extremely rare. Febrile seizures (seizures triggered by fever) occur in approximately 1 in 3,000 vaccinated children, compared to 1 in 200 children who get measles. These febrile seizures, while frightening for parents, do not cause long-term harm. The risk of serious allergic reaction (anaphylaxis) is approximately 1-2 per million doses.

How Long Does It Take to Recover from Measles?

Most people recover from measles within 2-3 weeks. The fever typically subsides within 5-6 days after the rash appears, followed by gradual improvement. However, the immune system remains weakened for weeks to months afterward, increasing susceptibility to other infections. Full recovery without complications is expected in most cases.

The timeline for recovery from measles follows a generally predictable pattern, though individual experiences can vary. The acute illness – characterized by high fever, respiratory symptoms, and rash – typically lasts about 10-14 days from the onset of the first symptoms. Most people begin feeling significantly better within a week after the rash appears as the fever subsides and the worst of the symptoms resolve.

The rash typically fades over 5-7 days in the same head-to-toe pattern in which it appeared. As it fades, it often leaves behind a brownish discoloration (post-inflammatory hyperpigmentation) and sometimes fine, powdery scaling of the skin. These skin changes are temporary and gradually resolve over the following weeks without treatment.

However, full recovery extends beyond the resolution of visible symptoms. Fatigue and weakness are common for several weeks after the acute illness. More concerning is the phenomenon of immune suppression that follows measles infection. Research has shown that measles can deplete the body's "immune memory," erasing previously acquired immunity to other pathogens and leaving individuals more susceptible to various infections for months after recovery.

Return to normal activities

Patients with measles should remain isolated until they are no longer contagious – at least 4 days after the rash appears. This means staying home from school, work, and other public places to prevent spreading the infection. Children should not return to school or childcare until they are no longer contagious and feel well enough to participate in normal activities.

After the isolation period, gradual return to normal activities is appropriate as the patient feels able. However, given the immune suppression that follows measles, it may be wise to avoid crowded places and close contact with sick individuals for several weeks after recovery to reduce the risk of secondary infections.

How Can You Prevent Measles?

Vaccination is the only reliable way to prevent measles. The MMR vaccine is 97% effective with two doses. If exposed to measles, post-exposure vaccination within 72 hours or immunoglobulin within 6 days can prevent or reduce disease severity. Isolation of infected individuals prevents community spread.

Prevention of measles relies primarily on vaccination, which remains the single most effective strategy for protecting individuals and communities from this highly contagious disease. When enough people in a community are vaccinated (approximately 95% or more), herd immunity develops, which protects even those who cannot be vaccinated, such as infants too young for vaccination, pregnant women, and immunocompromised individuals.

Post-exposure prophylaxis

If an unvaccinated person is exposed to measles, there are options for preventing or reducing the severity of illness if acted upon quickly. The MMR vaccine, when given within 72 hours of exposure, may prevent measles or result in milder illness. This is because the vaccine can "race" the natural virus, stimulating protective immunity before the virus has time to establish infection.

For those who cannot receive the live vaccine (infants under 6 months, pregnant women, severely immunocompromised individuals), immunoglobulin (antibody preparation) can be given within 6 days of exposure. Immunoglobulin provides temporary passive immunity that may prevent measles or modify the disease to a milder form.

Isolation and infection control

Infected individuals should be isolated from susceptible contacts during the contagious period (4 days before to 4 days after rash onset) to prevent transmission. In healthcare settings, airborne infection isolation precautions are required, including a negative-pressure room and N95 respirators for healthcare workers, given the virus's ability to spread through the air.