Measles

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Introduction

Measles, also known as rubeola, is a highly contagious respiratory viral infection. It is a notifiable disease in the United Kingdom.1

Prior to the introduction of the measles vaccine in 1968, there were around 160,000 to 800,000 reported annual notifications in the UK, with peaks occurring every 2 years, and around 100 deaths due to acute measles occurred each year. 2

There were 808 confirmed cases of measles in England and Wales in 2019, and 79 in 2020.3

Although measles is more commonly seen in young children, those of any age can contract the disease if they are unvaccinated or have never been infected before.4

You might also be interested in our medical flashcard collection which contains over 1000 flashcards that cover key medical topics.

Aetiology

Measles is an airborne infection caused by a virus of the family Paramyxoviridae, genus morbillivirus. It is a single-stranded, spherical RNA virus.5,6

Measles is spread through respiratory droplets from coughing, sneezing, close personal contact, or direct contact with nasal or throat secretions.1 The virus can remain transmissible for up to two hours after it is spread on surfaces.6

The incubation period lasts around 10 days.5

Once infected, the person is infectious from the onset of symptoms till four days after the rash has appeared.1

A person who has been infected with measles will develop lifelong immunity.6


Risk factors

Risk factors for measles include: 5

  • Exposure to the measles virus
  • Lack of prior immunisation against measles
  • Failure to respond to the vaccine

Clinical features

History

After the incubation period, a prodromal phase follows, after which the rash develops. The prodromal phase lasts 2 – 4 days.1

Typical symptoms in the prodromal phase include:

  • A fever of 39°C or more without antipyretics, decreases after the rash develops
  • Cough
  • Conjunctivitis
  • Coryza
  • Diarrhoea

Other important areas to cover in the history include:

  • Past medical history: previous infection with measles confers lifelong immunity
  • Vaccination status

Clinical examination

Typical clinical findings in measles include:1,6

  • Koplik’s spots: These are two to three mm wide, small, red spots with blue-white centres seen on the buccal mucosa (Figure 1). Koplik’s spots are pathognomonic of measles; appearing one to two days before the onset of the rash and may persist for a further one to two days.
  • Erythematous, maculopapular rash: beginning on the face and behind the ears, it spreads downwards towards the trunk and limbs over three to four days and appears on the hands and feet last (Figure 2). It may become confluent as it spreads. The rash lasts for about five days before fading with brown discolouration and may be accompanied by desquamation.

 


Differential diagnoses

Consider an alternative diagnosis in those who are immunised, their clinical features are atypical, have a lack of history of contact with measles, have not travelled to endemic countries, and if there are no local outbreaks.1

For more information, see the Geeky Medics guide to infectious rashes in paediatrics.

Table 1. Differential diagnoses of measles.1,5,9,10

Differential diagnosis Differentiating features

Rubella

Typically a mild illness; presents with a maculopapular rash which spreads in a similar pattern as measles but is not confluent, and usually resolves in three days.

No Koplik’s spots.

Parvovirus B19 (erythema infectiosum)

Generally, a mild, self-limiting illness that typically presents with a bright red rash on the cheeks, followed by a red, lacy rash on the rest of the body.

No Koplik’s spots.

Arthralgia and arthritis may be seen in adults.

Herpes virus type 6 (roseola infantum)

Usually, a mild illness which may also be asymptomatic. A maculopapular rash appears after fever breaks.

No Koplik’s spots.

Streptococcal infection (e.g. scarlet fever)

 

A sore throat is typically a prominent feature. On examination, a ‘strawberry tongue’ may be seen.

No cough.

A maculopapular rash develops, first seen on the abdomen, after which it spreads to the back and limbs 12–24 hours following symptom onset.

No Koplik’s spots.

Early meningococcal disease

A maculopapular rash may be seen, but it becomes purpuric in later stages. The rash is non-blanching when a glass is pressed against it.

No Koplik’s spots.

Kawasaki disease

Usually diagnosed in children with a fever of 39°C or more for at least five days and at least four of the following to fit the diagnostic criteria (or echocardiographic evidence of coronary artery aneurysms):

  • Inflammation and irritation of the oral and pharyngeal mucosa
  • Erythema, oedema and/or desquamation of extremities
  • Bilateral dry conjunctivitis
  • Polymorphic rash starting on the soles, palms, and perineum then spreads to the trunk and extremities
  • Cervical lymphadenopathy

No Koplik’s spots.

Ebstein-Barr virus infection (infectious mononucleosis)

Patients present with fever, sore throat, and lymphadenopathy; pharyngeal exudates, and hepatosplenomegaly may also be seen.

A non-specific rash (may be macular, petechial, urticarial, erythema multiforme-like, or maculopapular) may be seen in those who were treated with amoxicillin.

No Koplik’s spots.

Drug eruption

Typically follows a recent history of medication or drug ingestion.


Investigations

Consider a diagnosis of measles in those presenting with a fever of 39ºC or more without antipyretics, cough, coryza, conjunctivitis, and the maculopapular rash.1

If a diagnosis of measles is suspected, the local health protection team should be notified and confirmation of the diagnosis using serology is required.1

A measles-specific IgM/IgG serology (ELISA) is generally performed, and the presence of measles-specific IgM indicates acute infection.5


Management

Measles is usually a self-limiting condition, its symptoms tend to resolve in about a week.1

General supportive treatment for measles includes:1

  • Rest
  • Advice regarding adequate fluid intake
  • Antipyretics: paracetamol/ibuprofen for symptomatic relief

Some patients, depending on severity, may also be given vitamin A.5

People with suspected measles should not attend school or work for at least four days after the rash has appeared and should avoid contact with those who are susceptible (unimmunised children and adults, pregnant women, and immunocompromised individuals).1

Vaccination

The measles, mumps, and rubella (MMR) vaccine, containing live attenuated strains of the virus, is used to prevent measles infection. The MMR vaccine is offered as part of the national immunisation programme and is given in two doses, the first dose (MMR1) at 12 months and the second dose (MMR2) at three years and four months.11

The vaccine may also be given as effective post-exposure prophylaxis, provided that the patient is over six months old and is offered within 72 hours of exposure.6

National coverage of MMR1 and MMR2 in children aged five years was 86.6% in 2020-21, compared to 86.8% in the previous year, lower than the national target of 95%.12

Of those vaccinated, 95% are protected against measles after MMR1 and 99% after both MMR1 and MMR2.5


Complications

Complications tend to be more severe in infants, adults, those who are pregnant, immunocompromised, and the chronically ill or malnourished. Usually, they affect the respiratory system and the central nervous system.1

Possible complications of measles include:1,5,6

  • Otitis media
  • Pneumonia: occurs either early in the illness with pulmonary involvement of measles or later, as a result of bacterial superinfection.
  • Tracheobronchitis
  • Convulsions
  • Encephalitis
  • Subacute sclerosing panencephalitis (SSPE): a rare degenerative disease of the CNS, causing seizures and affecting motor, cognitive, and behavioural function. Usually seen in children, more commonly boys, who contracted measles at a very young age. SSPE occurs five to ten years after initial exposure to the virus and is always fatal.
  • Sight impairment: patients with vitamin A deficiency are at an increased risk of death and severe sight impairment.
Measles infection in pregnancy

Measles acquired in pregnancy can lead to:13

  • Miscarriage or stillbirth
  • Premature birth
  • Low birthweight

A potentially fatal pneumonitis can also occur in the mother as a result of measles infection in pregnancy.6


Key points

  • Measles is a highly contagious respiratory infection caused by an RNA morbillivirus of the paramyxovirus family.
  • Measles is spread through respiratory droplets from coughing, sneezing, close personal contact, or direct contact with nasal or throat secretions.
  • Patients present with fever, cough, conjunctivitis, coryza, and the characteristic erythematous maculopapular rash. Pathognomonic Koplik’s spots may also be seen on the buccal mucosa.
  • Measles is usually self-limiting, with symptoms resolving in about a week.
  • The MMR vaccine is used to prevent measles.
  • Complications of measles include otitis media, pneumonia, encephalitis, subacute sclerosing panencephalitis and blindness.

Reviewer

Dr Zhivka Chuperkova

Paediatrician, Paediatric Neurologist
Medical University of Varna


Editor

Dr Chris Jefferies


References

  1. NICE CKS. Measles. Last revised in March 2018. Available from: [LINK]
  2. UK Health Security Agency. Measles: the green book, chapter 21. Last updated 31 December 2019. Available from: [LINK]
  3. UK Health Security Agency. Confirmed cases of measles, mumps and rubella in England and Wales: 1996 to 2021. Updated 1 February 2022. Available from: [LINK]
  4. NHS inform. Measles. Last updated: 29 April 2022. Available from: [LINK]
  5. BMJ Best Practice. Measles infection. Last updated on 08 Apr 2022. Available from: [LINK]
  6. Patient.info. Measles. Last edited 30 Sep 2020. Available from: [LINK]
  7. CDC Public Health Image Library. ID#: 6111. Licence: [Public domain]
  8. CDC Public Health Image Library. ID#: 3168. Licence: [Public domain]
  9. Patient.info. Kawasaki Disease. Last edited 7 May 2020. Available from: [LINK]
  10. NICE CKS. Glandular fever (infectious mononucleosis). Last revised in July 2021. Available from: [LINK]
  11. NHS. MMR (measles, mumps and rubella) vaccine. Last reviewed on 8 April 2020. Available from: [LINK]
  12. NHS Digital. Childhood Vaccination Coverage Statistics – 2020-21. Published on 30 Sep 2021. Available from: [LINK]
  13. NHS. Measles. Last reviewed on 21 February 2022. Available from: [LINK]

 

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