Rubella
Exam Tips
- Do not diagnose rubella clinically alone in UK exams: state that laboratory confirmation is required and that rubella is notifiable to the HPT.
- Classic node pattern is postauricular + suboccipital + posterior cervical lymphadenopathy, often preceding rash.
- Rash timing pearl: incubation about 14-21 days; infective from 7 days before to up to 10 days after rash onset; highest infectivity at rash eruption.
- In any pregnant patient (especially <20 weeks) with rubella-like rash, exclude rubella even if vaccinated and test for parvovirus B19 in parallel.
- CRS risk is gestation-dependent: highest in first trimester, falls after 11-16 weeks, rare after 16 weeks except possible hearing loss; know the triad (deafness, eye defects, congenital heart disease). See Figure: CRS triad diagram and fetal-risk-by-week chart.
Definition
Rubella (German measles) is an acute infection caused by rubella virus (a Rubivirus) and spread by respiratory droplets or direct contact with nasopharyngeal secretions. It is usually a mild, self-limiting febrile rash illness, but it is clinically important because maternal infection in early pregnancy can cause congenital rubella syndrome (CRS) with major fetal harm; therefore suspected cases require laboratory confirmation and public health notification in the UK.
Pathophysiology
After inoculation, rubella virus replicates in the nasopharynx and regional lymph nodes, then causes viraemia with dissemination to skin and other tissues, producing a transient maculopapular exanthem and lymphadenopathy. Incubation is typically 14-21 days (often rash at day 14-17), and infectivity runs from about 7 days before to 4-10 days after rash onset, peaking as the rash appears. In pregnancy, transplacental spread can disrupt organogenesis and vascular development; fetal risk is highest in the first 8-10 weeks (severe multi-organ defects common), falls in weeks 11-16, and is low after 16 weeks (though hearing loss can still occur up to around 20 weeks). See Figure: gestational-age risk curve for CRS and transplacental spread timeline.
Risk Factors
- No or incomplete MMR vaccination (fewer than 2 documented doses)
- Recent close contact with a person with suspected or confirmed rubella in the previous 3 weeks
- Travel to, or residence in, regions where rubella remains endemic
- Pregnancy without proven immunity, especially before 20 weeks' gestation
- Not spending childhood in the UK (possible lower historical vaccine coverage depending on country of origin)
- Household or institutional exposure during a local outbreak
Clinical Features
Symptoms
- Often asymptomatic (up to half of infections)
- Mild prodrome: low-grade fever, malaise, coryzal/URTI symptoms
- Rash beginning on face/neck then spreading caudally over trunk and limbs
- Mild itch with rash in some patients
- Arthralgia or arthritis (particularly in adolescents/adult women)
- Mild non-purulent conjunctival irritation
Signs
- Pink/light-red discrete maculopapular rash, usually lasting 3-4 days
- Tender postauricular, suboccipital, and posterior cervical lymphadenopathy (can precede rash by 5-10 days)
- Temperature typically <39 degrees C
- Usually mild systemic upset compared with measles
- Occasional synovitis in small joints
Investigations
Management
Lifestyle Modifications
- Advise rest, oral hydration, and simple fever control
- Exclude from school/work and avoid contact with susceptible pregnant people for at least 5 days after rash onset (follow local UKHSA/HPT advice)
- Use droplet/contact hygiene measures at home (hand hygiene, respiratory etiquette, avoid sharing utensils during infectious period)
- Confirm and update MMR status after recovery for non-immune individuals (MMR is contraindicated during pregnancy)
- Urgently involve obstetric/infectious diseases teams for any suspected infection in pregnancy
Pharmacological Treatment
Antipyretic/analgesic (supportive care; no specific antiviral therapy)
- Paracetamol adult: 500 mg-1 g orally every 4-6 hours when required (max 4 g/24 h)
- Paracetamol child 1 month-11 years: 15 mg/kg every 4-6 hours (max 4 doses in 24 h)
- Ibuprofen adult: 200-400 mg orally three times daily with food when required (usual max 1.2 g/day OTC; up to 2.4 g/day on prescription)
- Ibuprofen child 3 months-11 years: 5-10 mg/kg per dose 3-4 times daily (max 30 mg/kg/day)
Avoid aspirin in under-16s (Reye syndrome risk). Use ibuprofen cautiously/avoid in dehydration, active GI ulceration, NSAID hypersensitivity, severe renal impairment, or NSAID-exacerbated asthma. In pregnancy, paracetamol is preferred for fever/pain; avoid routine NSAIDs, especially from 20 weeks onward unless specialist advice. Antibiotics are not indicated unless a separate bacterial diagnosis is confirmed.
Post-exposure and prevention
- MMR vaccine 0.5 mL subcutaneous injection (2-dose schedule, at least 1 month apart if catch-up required)
MMR is a live vaccine: contraindicated in pregnancy and severe immunosuppression. It is not useful as treatment for established rubella but is key for prevention and outbreak control.
Complications
- Miscarriage, intrauterine fetal death, or stillbirth after maternal infection
- Congenital rubella syndrome: sensorineural deafness, congenital cataract/other eye defects, congenital heart disease (classically PDA, pulmonary artery stenosis)
- Neurodevelopmental sequelae: microcephaly, developmental delay, autism-spectrum features, inflammatory CNS lesions
- Endocrine sequelae in CRS survivors (for example diabetes mellitus, thyroid dysfunction)
- Intrauterine growth restriction and chronic multisystem fetal inflammation (brain, liver, lung, bone marrow)
- Post-infectious arthritis/arthralgia (often prolonged in adults)
- Thrombocytopenic purpura (rare)
- Encephalitis and other rare neurologic complications (myelitis, optic neuritis, peripheral neuritis, Guillain-Barre syndrome)
Prognosis
In immunocompetent non-pregnant children and adults, rubella is usually mild and resolves within about 1 week, though joint symptoms can persist for weeks to months in some adults. Prognosis is markedly worse for fetal outcomes when non-immune maternal infection occurs early in pregnancy, with the greatest risk of severe CRS in the first trimester.
Sources & References
🏥BMJ Best Practice(1)
💊BNF Drug References(1)
- Ketorolac trometamol[contraindications]
✅NICE Guidelines(1)
- Rubella[overview]
📖Textbook References(2)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1497, 1498)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1497, 1498)[context]