Paediatrics chapters
Measles, mumps and rubella
The three viral illnesses prevented by MMR vaccine: how each spreads, the stages and signs, key complications such as pneumonia, SSPE, orchitis and congenital rubella, and treatment and prevention.
- Measles is a very infectious RNA paramyxovirus illness: 3-5 days of fever, cough, coryza and conjunctivitis with Koplik spots, then a maculopapular rash spreading from behind the ears and hairline downwards; pneumonia is the usual cause of death and every child gets vitamin A.
- Mumps gives tender parotid swelling that hides the angle of the jaw; meningoencephalitis, orchitis (after puberty) and pancreatitis are the main complications.
- Rubella is mild, with post-auricular and suboccipital nodes and a 3-day rash; its danger is congenital rubella syndrome (cataract, PDA, deafness) when a mother is infected early in pregnancy.
On this page
Overview
Measles, mumps and rubella are three RNA virus infections of childhood that share one vaccine (MMR). In Pakistan measles is the most important: it is very contagious, it kills malnourished children through pneumonia and diarrhoea, and it is a frequent question topic. Mumps is usually mild but gives orchitis and meningitis. Rubella is trivial in children but devastating to a fetus.
Measles (rubeola)
Aetiology and spread
- A single-stranded RNA paramyxovirus with one antigenic type; humans are the only natural host.
- Spread by droplets and the airborne route; extremely contagious.
- Infectious period: Akbar gives 3 days before to 6 days after the rash; Nelson gives roughly 4 days either side of the rash (from 5 days before) (1-2 days before symptoms). Both mean: the child spreads it before the rash is seen.
- Most common in malnourished children under 3 years; rare under 4-6 months because of maternal antibody; most cases occur in winter.
- The virus multiplies in the respiratory tract and nodes, then spreads by two viraemias to skin, lungs and other organs.
Pathology (exam terms)
- Warthin-Finkeldey cells: multinucleated giant cells in lymphoid tissue.
- Hecht giant cell pneumonia: measles pneumonitis in children with poor cell-mediated immunity; often fatal.
- Koplik spots: tiny foci of serous exudate and cell proliferation in the buccal mucosa.
Clinical features
Incubation: about 10-12 days to the first symptoms (Nelson 8-12 days; about 14 days to the rash).
| Stage | What you see |
|---|---|
| Prodrome (catarrhal), 3-5 days | High fever, cough, coryza, conjunctivitis (the "3 Cs"), photophobia, a harsh barking cough worse at night |
| Koplik spots | Grey-white grains on a red base inside the cheek, opposite the lower molars; appear just before the rash and vanish within about 12-24 hours |
| Rash stage | Fever climbs to 40-40.5 °C as the rash appears. Faint macules start behind the ears and along the hairline, spread to face, trunk and limbs over about 3 days, become confluent, then fade in the same order leaving brownish staining and fine (branny) peeling that clear in 7-10 days |
| Recovery | Fever settles once the rash reaches the feet; cough may linger |
- The "measly look": red eyes, puffy lids, swollen nasal bridge, running nose and a miserable face.
- Others: posterior cervical nodes, mild splenomegaly, abdominal pain from mesenteric nodes; a transverse inflamed line on the lid margin (Stimson line).
- Severity of illness parallels the extent and confluence of the rash.
- Haemorrhagic (black) measles: confluent bruise-like rash with bleeding from mouth, nose or gut; very toxic, often fatal.
- Modified measles: mild, short illness in children with partial immunity (maternal antibody, immunoglobulin, vaccination before 12 months). Akbar notes inapparent cases do not spread infection.
Koplik spots are pathognomonic but short-lived; fever, rash, cough and conjunctivitis together are diagnostic in practice.
In roseola the rash comes as the fever falls; in measles the fever rises further when the rash appears.
Complications
| System | Complication |
|---|---|
| Respiratory | Otitis media (commonest, Nelson); bronchopneumonia (viral or secondary bacterial: pneumococcus, Staph. aureus, group A strep) is the commonest cause of death |
| Gut | Post-measles diarrhoea, often fatal in the malnourished; cancrum oris (noma); tipping into marasmus or kwashiorkor |
| Eye | Conjunctivitis, corneal ulceration, rarely optic nerve damage; vitamin A lack makes eye damage worse |
| Nervous system | Acute encephalitis in about 1 per 1000 cases, a few days after the rash; CSF shows lymphocytes, raised protein, normal glucose. SSPE years later |
| Immune | Measles depresses cell-mediated immunity: the tuberculin test turns negative and quiescent TB can flare |
| Others | Myocarditis, thrombocytopenia |
Akbar notes that nephrotic syndrome, eczema and asthma may temporarily improve after measles.
Subacute sclerosing panencephalitis (SSPE)
- A slow persistent measles virus infection of the brain, appearing on average 7-10 years after measles; Nelson puts the rate at about 1 per million cases.
- Measles at a young age (before 2-4 years) raises the risk.
- Features: falling school performance and behaviour change, then myoclonic jerks, dystonia and choreoathetosis, dementia, and death.
- Diagnosis: raised measles antibody in CSF, burst-suppression pattern on EEG (periodic complexes), brain biopsy.
- Treatment: supportive. Akbar lists isoprinosine (with or without interferon) and carbamazepine for jerks; there is no cure and it is always fatal.
Investigations
- Diagnosis is clinical.
- White cell count is low (leucopenia) with relative lymphocytosis.
- Measles IgM appears 1-2 days after the rash and confirms the diagnosis; virus RNA by PCR; giant cells in nasal smears in the prodrome.
- Report suspected cases to the public health team.
Differential diagnosis of the rash
| Illness | Pointer |
|---|---|
| Rubella | Milder, prominent nodes, no Koplik spots, low fever |
| Roseola infantum | Rash appears as the fever settles |
| Scarlet fever | Fine sandpaper rash, strawberry tongue |
| Kawasaki disease | No Koplik spots, no heavy prodromal cough, thrombocytosis |
| Meningococcaemia | Petechial rash, shock, no cough or conjunctivitis |
| Drug rash | Drug history, no cough |
Management
- No specific antiviral: supportive care at home unless complicated.
- Paracetamol for fever, fluids and nutrition (continue breastfeeding), clean the eyes and nose, humidified room for cough.
- Antibiotics only for secondary bacterial infection (pneumonia, otitis).
- Vitamin A for every child with measles (reduces deaths and eye damage), once daily for 2 days:
| Age | Dose (Akbar) |
|---|---|
| 12 months and older | 200,000 IU |
| 6-11 months | 100,000 IU |
| Under 6 months | 50,000 IU |
If there are signs of vitamin A deficiency, a third dose is given 2-4 weeks later.
Vitamin A is given to all children with measles, not only to the malnourished.
Prevention
- Live attenuated vaccine (subcutaneous, 0.5 ml). Akbar's EPI table lists measles-1 at 9 months and measles-2 at 15 months; in an epidemic it may be given from 6 months. The current national schedule uses a measles-rubella vaccine; check the latest timing at EPI Pakistan (checked 8 Nov 2026).
- Efficacy is lower at 9 months (maternal antibody) than at 12 months, which is why a second dose is given.
- After exposure: vaccine within 72 hours can prevent disease (vaccine incubation is shorter than the wild virus); immunoglobulin (0.25 ml/kg) within 6 days for infants under 6 months, pregnant women and the immunocompromised.
- Contraindications to live vaccine: pregnancy, severe immunodeficiency or high-dose steroids, recent immunoglobulin. Children with HIV who are not severely immunosuppressed should be vaccinated.
Mumps
Aetiology and epidemiology
- RNA paramyxovirus; spread by droplets, direct contact and saliva-soiled objects.
- Peak age 5-10 years; about 30-40% of infections are subclinical.
- Incubation 12-25 days (usually 14-18).
- Most infectious from 1-2 days before to 5 days after the parotid swelling.
- One attack gives lasting immunity.
Clinical features
- Little or no fever, malaise, earache, pain on chewing; sour drinks make the pain worse.
- Parotid swelling (one or both sides): fills the hollow behind the jaw, hides the angle of the jaw and pushes the ear lobe up and outward; reaches its maximum in 1-3 days and settles over about a week.
- Redness at the opening of Stensen's duct; the submandibular glands may also swell.
Complications
| Complication | Key facts |
|---|---|
| Meningoencephalitis | Commonest extra-glandular illness in children; CSF cells are found in many more than show symptoms; usually benign |
| Epididymo-orchitis | Common after puberty, rare before; usually one-sided, in the first week; testis may shrink but sterility is rare |
| Pancreatitis | Epigastric pain and vomiting; raised amylase |
| Deafness | Rare; from inflammation of the auditory nerve |
| Others | Oophoritis, thyroiditis, myocarditis, arthritis |
Diagnosis and management
- Clinical; serum amylase rises with the swelling; mumps IgM; leucopenia with relative lymphocytosis.
- Differentials: other viral parotitis, suppurative parotitis (one-sided, red, pus from Stensen's duct, Staph. aureus, high white count), cervical adenitis, drug-related or recurrent parotitis, stone in the duct.
- Treatment is supportive: paracetamol or ibuprofen, soft diet, rest, scrotal support for orchitis. No antiviral; immunoglobulin is not useful.
Mumps = "Mouth, Meninges, Male gonads, Pancreas".
Rubella (German or 3-day measles)
Aetiology and spread
- Single-stranded RNA togavirus; humans are the only host.
- Spread by droplets; most contagious from about 2 days before to 5-7 days after the rash.
- 25-50% of infections are subclinical. Maternal antibody protects for about 6 months.
Clinical features
- Incubation 14-21 days (typically 16-18).
- Mild prodrome, low-grade fever.
- Tender post-auricular, posterior cervical and suboccipital lymph nodes: the hallmark.
- Pink maculopapular rash that starts on the face, spreads down and lasts about 3 days; lighter and less confluent than measles.
- Forchheimer spots: pink spots on the soft palate in about 20%.
- Arthritis of small hand joints, mainly in adolescent and adult females.
Diagnosis and treatment
- Rubella IgM (positive about 5 days after onset) or a fourfold rise in IgG.
- Treatment is supportive. Complications in children are rare (thrombocytopenia, encephalitis).
Congenital rubella syndrome (CRS)
Risk depends on timing of maternal infection:
| Maternal infection | Fetal effect (Nelson) |
|---|---|
| First trimester | Fetal infection in over 90%; defects in up to 85% if in the first weeks |
| 13-16 weeks | Abnormalities in about 35% |
| After about 4 months | Disease rare |
Classic findings:
- Eyes: cataract, glaucoma, retinopathy (salt-and-pepper), microphthalmia.
- Heart: PDA and peripheral pulmonary artery stenosis.
- Ears: sensorineural deafness (commonest single defect).
- Brain: microcephaly, intellectual disability, meningoencephalitis.
- Newborn: growth restriction, hepatosplenomegaly, jaundice, thrombocytopenia, "blueberry muffin" rash, bone lucencies.
Infants with CRS shed virus for about a year and must be kept away from pregnant women.
Cataract + PDA + deafness = congenital rubella.
Rubella vaccine is not given in pregnancy and pregnancy is avoided for 28 days after it, yet no case of CRS has been reported after accidental vaccination.
MMR vaccine at a glance
- Live attenuated; Nelson's schedule is 12-15 months and 4-6 years; Pakistan's EPI uses measles-rubella at 9 and 15 months (check the current schedule).
- The second dose catches primary vaccine failures, not a booster.
- Contraindications: pregnancy, severe immunodeficiency, steroids at over 2 mg/kg/day for over 14 days, recent immunoglobulin, anaphylaxis to neomycin or gelatin.
- Side effects: mild fever or a measles-like rash; febrile seizures; transient joint pains in older girls from the rubella part.
Expect: Koplik spots and their site; the order of rash spread and brown staining; fever rising with the rash (unlike roseola); pneumonia as the main killer and otitis media as the commonest complication; vitamin A doses by age; encephalitis rate and SSPE (EEG, CSF antibody, myoclonus); tuberculin anergy after measles; post-exposure vaccine within 72 hours and immunoglobulin within 6 days; mumps parotid signs, orchitis after puberty, raised amylase; rubella nodes and Forchheimer spots; congenital rubella triad and timing risk; MMR contraindications.
Quick revision
- Measles: RNA paramyxovirus; fever, cough, coryza, conjunctivitis; Koplik spots; rash from hairline downwards.
- Pneumonia kills; otitis is commonest; diarrhoea and noma in the malnourished.
- Vitamin A for all: 200,000 / 100,000 / 50,000 IU by age, 2 days.
- SSPE: years later, myoclonus, burst-suppression EEG, CSF measles antibody, fatal.
- Post-exposure: vaccine within 72 hours, immunoglobulin within 6 days.
- Mumps: parotid swelling hiding the jaw angle; orchitis after puberty; meningoencephalitis benign.
- Rubella: posterior nodes, 3-day rash; CRS = cataract, PDA, deafness.
- EPI (Akbar): measles at 9 and 15 months.
Written by The House Job from standard references (Basis of Paediatrics by Pervez Akbar; Nelson Essentials of Paediatrics; Park's Preventive and Social Medicine).
FAQ
Why does measles kill children in poor countries?
Measles weakens immunity and gut lining, so pneumonia, diarrhoea and malnutrition follow, especially in children who are already undernourished or short of vitamin A.
Can measles be prevented after contact?
Yes. Live vaccine given within 72 hours, or immunoglobulin within 6 days for high-risk contacts, can prevent or soften the illness.
Does mumps orchitis cause infertility?
The affected testis may shrink, but because it is usually one-sided, true sterility is rare.
Why is rubella important if it is so mild?
Infection early in pregnancy can damage the fetus, causing cataract, heart defects and deafness, so girls are immunised before childbearing age.