Measles

Measles

Definition

• Acute viral illness caused by the measles virus

• Characterised by fever, cough, coryza, conjunctivitis, and a descending maculopapular rash

• Highly contagious, with an incubation period of 10–14 days

• Can lead to severe complications, particularly in young children, pregnant women, and immunocompromised individuals

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Presentation

• Prodromal phase includes fever over 38°C, malaise, dry cough, runny nose, and red eyes

• Koplik spots: Small white lesions on the buccal mucosa appearing 1–2 days before the rash (pathognomonic)

• Rash: Descending, blotchy red maculopapular rash starting at the hairline and progressing downward, typically non-itchy

• Other features may include otitis media, pneumonia, and diarrhoea during the illness

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Differential Diagnosis

• Rubella: Similar rash but milder, with postauricular lymphadenopathy

• Scarlet fever: Sandpaper rash with strawberry tongue following streptococcal infection

• Dengue: Febrile illness with rash and myalgia, usually with relevant travel history

• Drug eruption: Rash due to medications, lacking respiratory or conjunctival symptoms

• Kawasaki disease: Prolonged fever with rash, conjunctivitis, and mucosal changes, but with distinct cardiac involvement

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Investigations

• Nasopharyngeal swab or urine PCR: Preferred diagnostic tests if performed within 3 weeks from rash onset

• Serology: Measles IgM and IgG antibody testing if PCR is unavailable

• Full blood count: May reveal lymphopenia during the acute phase

• Chest X-ray: To evaluate for complications such as pneumonia when indicated

• Additional tests: Consider screening for other infections (e.g., COVID-19) if clinically warranted

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Management

• Isolation: Place the patient in a closed room and ensure staff use appropriate PPE (surgical mask plus N95)

• Infection control: Perform terminal cleaning after patient departure and trace contacts who were exposed up to 30 minutes post-exposure

• Notification: Report immediately to public health authorities

• Post-exposure prophylaxis:

  • MMR vaccine within 72 hours for unvaccinated or exposed individuals

  • Immunoglobulin within 6 days for high-risk groups including immunocompromised individuals, pregnant women, and infants under 6 months

• Supportive care:

  • Ensure adequate hydration and administer antipyretics such as paracetamol for fever

  • Monitor for complications like pneumonia, encephalitis, or otitis media

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Prevention

• Vaccination:

  • Two doses of MMR vaccine provide over 99% protection; aim for 95% coverage to maintain herd immunity

  • Offer catch-up vaccination for individuals born between 1966 and 1994 who may have received only one dose

  • In outbreak settings, consider MMR vaccination from 6 months of age, with the first dose repeated if administered before 11 months

• Infection control in practice:

  • Isolate symptomatic patients on arrival and screen for travel history and exposure

  • Maintain current immunisation records for staff and patients

• Public health measures:

  • Follow guidelines for contact tracing and outbreak management during increased measles activity

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Notes

• Infectious period: Patients are contagious from 5 days before to 5 days after rash onset

• Complications: Approximately 10% of cases may result in pneumonia, otitis media, or acute encephalitis; subacute sclerosing panencephalitis is a rare, fatal long-term complication

• Detailed documentation of exposures and prompt public health notification are essential in outbreak settings

• Educate patients and caregivers on the critical importance of vaccination and early isolation measures

• Consider epidemiological factors and current global measles trends, including decreased immunisation rates and increased travel-related cases