Measles
Aetiology and epidemiology
Measles is caused by a paramyxovirus and occurs in epidemics in winter and spring. It is still a leading cause of morbidity and mortality; especially in less developed countries. The infection is spread by droplets, or, less commonly, by aerosol spread. The primary site of infection is the nasopharynx.
The incubation period for measles is typically 7-21 days. The infectivity period usually commences several days before the onset of the symptoms and lasts until up to 4 days after the appearance of the characteristic rash.
Clinical assessment
Measles is characterised by an erythematous maculopapular rash beginning on the head, with a cephalocaudal progression.
The clinical case definition of this disease has been defined as a fever >38.3°C or ‘felt hot’ if not measured, a generalised maculopapular rash lasting in excess of 3 days and at least one of: cough, conjunctivitis or coryza.
Other associated signs described in measles are:
- Pin-point elevations of the soft palate, which coalesce to cause a reddened pharynx
- Blue-white Koplik’s spots occurring on the buccal mucosa opposite the second molar and lasting around 1-2 days
 |
 |
| Fig 1: Typical measles rash | Fig 2: Koplik’s spots are pathognomonic of measles |
Investigations
The clinical case definition of measles has a low positive predictive value in settings of low prevalence and therefore a laboratory diagnosis is important [3].
The investigation for measles is performed using oral fluid or serum sampling for measles immunoglobulin M (IgM) antibody.
In acute cases, measles can be detected by taking throat swabs or testing the urine.
Management
Measles is a notifiable illness and notification is required based on clinical suspicion.
Children diagnosed with measles should be kept off school until 5 days after the appearance of the rash.
The treatment of measles is largely symptomatic and the majority of children will recover uneventfully.
Patients should be advised to attend, however, if symptoms do not resolve within 1 week or if unusual symptoms develop.
Additional treatment options
High fatality rates are still seen in more vulnerable patients, e.g. the immunocompromised, the malnourished and those living in less developed countries. In these instances, a range of additional treatment options can be considered.
| Prophylactic antibiotics | Shown to reduce the incidence of some complications in children in areas with high case-fatality rates, e.g. pneumonia, otitis media and tonsillitis [4] |
| Human normal immunoglobulin (HNIG) | Shown to prevent or reduce the severity of an attack in infants under 12 months, immunocompromised children and pregnant patients (if used within 72 hours of exposure) |
| Measles, Mumps and Rubella (MMR) vaccination | Indicated in healthy unimmunised or partially immunised children if used within 72 hours of exposure to measles |
| Vitamin A supplements | Shown to reduce mortality and pneumonia-specific mortality in children under two years, for example in less developed countries [5] |
Complications
A number of complications can potentially arise from measles:
- Otitis media
- Bronchopneumonia
- Laryngotracheobronchitis
- Diarrhoea
- Acute encephalitis
- Sub-acute sclerosing pan encephalitis