PassFinals
Paediatrics

Measles

A highly contagious morbillivirus infection causing fever, cough, coryza, conjunctivitis, Koplik spots and a cephalocaudal maculopapular rash, requiring immediate isolation and public-health action.

In a nutshell

Measles causes fever, cough, coryza, conjunctivitis and Koplik spots followed by a face-to-body maculopapular rash. It is extremely contagious and notifiable: isolate and contact the health protection team immediately. Treatment is supportive, with urgent attention to pneumonia, dehydration, encephalitis and vulnerable contacts.

Classic presentation

An undervaccinated child with high fever, the three Cs and Koplik spots, followed by a rash beginning behind the ears or on the face and spreading downwards.

Key points

  • The three Cs are cough, coryza and conjunctivitis.
  • Koplik spots appear on the buccal mucosa before or around the start of the rash.
  • The rash spreads cephalocaudally and may become confluent.
  • Measles is infectious from 4 days before to 4 days after rash onset.
  • Suspected measles is isolated and notified without waiting for PCR.
  • Serious complications include pneumonia, dehydration and encephalitis; risk is higher in infants, pregnancy and immunocompromise.
  • Vitamin A is not a routine outpatient prescription; hospitalised high-risk children require specialist discussion.
  • Close contacts need UKHSA risk assessment for prompt MMR/MMRV or immunoglobulin.

First-line investigation

Clinical diagnosis plus UKHSA-directed oral-fluid/PCR/serological confirmation, without delaying isolation or notification.

Management

Isolate and notify

  • Keep suspected measles out of shared waiting areas, isolate promptly and contact the local UKHSA health protection team without waiting for PCR.3,1,4

Assess severity and confirm through UKHSA

  • Assess respiratory, neurological and hydration status, then arrange the UKHSA-directed testing pathway; do not delay clinical management while awaiting results.1,3

Treat the patient and complications

  • Give fluids and age-appropriate symptom relief, treat bacterial complications, and seek specialist advice for pneumonia, neurological disease, severe immunocompromise or hospitalised high-risk children.2,3,6

Protect susceptible contacts

  • Use current UKHSA contact guidance for prompt MMR/MMRV vaccination or human normal immunoglobulin according to age, pregnancy, immune status, exposure and contraindications.1,3,5

Complete exclusion and prevention

  • Exclude for at least 4 days after rash onset, give written safety-netting and complete vaccination catch-up for susceptible household contacts.2,5

Exam traps

  • Do not wait for laboratory confirmation before isolating a clinically suspected case.
  • Measles is not just a rash: pneumonia, dehydration and encephalitis are the important complications.
  • A close contact may need post-exposure vaccination or immunoglobulin even when the index patient is not yet laboratory-confirmed.
  • Vitamin A is specialist, not routine outpatient, treatment in current NHS England guidance.
  • MMR/MMRV vaccination status must be checked for the whole household.

Illustrations

Koplik spotsClinical photograph of small white Koplik spots on the buccal mucosa, pathognomonic of measles and appearing before the rash.CDC, Wikimedia Commons · Public domain
Measles rashA clinical photograph showing the widespread erythematous maculopapular, partly confluent rash of measles across the trunk.Photo Credit: Content Providers(s): CDC/Dr. Heinz F. Eichenwald, Wikimedia Commons · Public domain

Key sources

  1. UKHSA: National measles guidelines (Current England guidance on suspected-case recognition, testing, isolation, notification and post-exposure management.)Updated 30 Jul 2026
  2. NHS: Measles (Current NHS information on symptoms, complications, exclusion and self-care.)
  3. NHS England: Measles guidance for healthcare services (Current NHS provider guidance on triage, isolation, testing, high-risk groups, complications and contacts.)Updated 21 May 2026
  4. UKHSA: Notifiable diseases and how to report them (Current England notification requirements; suspected measles is urgent.)Updated 19 May 2026
  5. NHS: MMR and MMRV vaccine (Current NHS vaccination schedule and catch-up information.)
  6. BNF online (Current UK prescribing information for symptomatic treatment and medicines used for complications.)
  7. UKHSA: Measles, the Green Book chapter 21 (Current UK measles immunisation and MMRV schedule guidance.)Updated 14 Apr 2026

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.