Rubella (German Measles)
Summary
Rubella is a mild viral illness caused by the Rubella virus (Togaviridae family). In children and adults, it typically presents with low-grade fever, maculopapular rash (Starts on face, spreads downwards), and characteristic posterior cervical and suboccipital lymphadenopathy. The illness is usually self-limiting and mild. However, the critical importance of rubella lies in its teratogenic potential – infection during early pregnancy (Especially first trimester) can cause Congenital Rubella Syndrome (CRS), which includes cataracts, congenital heart defects, sensorineural deafness, and developmental delay. Rubella is now rare in countries with high MMR vaccination coverage but remains a concern in unvaccinated populations and imported cases. Rubella is a notifiable disease in the UK. Prevention through MMR vaccination is the key public health strategy. [1,2,3]
Clinical Pearls
"Mild in Children, Catastrophic in Pregnancy": Postnatal rubella is trivial. Congenital rubella causes devastating multi-system defects.
"Posterior Cervical + Suboccipital Lymphadenopathy": Classic finding. Nodes behind the ears and at the base of the skull.
"First Trimester = Highest Risk": Rubella infection in first 12 weeks of pregnancy = 85-90% risk of CRS or fetal loss.
"MMR Vaccine = Elimination": Rubella is vaccine-preventable. Two doses of MMR provide lifelong immunity.
Demographics
| Factor | Notes |
|---|---|
| Age | Historically affects children 5-9 years. Now rare due to vaccination. |
| Sex | Equal. |
| Incidence (UK) | Very rare. less than 50 cases/year (Thanks to MMR). |
| Global | Remains endemic in some developing countries with low vaccine coverage. |
Transmission
| Factor | Notes |
|---|---|
| Route | Respiratory droplets. Direct contact with nasopharyngeal secretions. |
| Incubation Period | 14-21 days (Average 16-18 days). |
| Infectious Period | 7 days before rash to 7 days after rash appears. Most infectious when rash erupts. |
Rubella Virus
| Feature | Notes |
|---|---|
| Family | Togaviridae. |
| Genus | Rubivirus. |
| Genome | Single-stranded positive-sense RNA. |
| Serotypes | One serotype (Infection or vaccination confers lifelong immunity). |
Postnatal Rubella (Children/Adults)
| Feature | Notes |
|---|---|
| Prodrome | 1-5 days. Low-grade fever, Malaise, Headache, Mild conjunctivitis, Coryza. Often minimal or absent in children. |
| Lymphadenopathy | Posterior Cervical, Suboccipital, Post-auricular. Tender. Appears before rash. Persists for weeks. |
| Rash | Maculopapular (Pink-red spots). Starts on face → Spreads to trunk and limbs within 24 hours. Fades by Day 3 ("Three-Day Measles"). Non-confluent. |
| Arthralgia / Arthritis | Common in adolescent girls and adult women. Affects fingers, Wrists, Knees. Self-limiting. |
| Subclinical Infection | ~25-50% of rubella infections are asymptomatic. |
Differentiating Features (Rash)
| Feature | Rubella | Measles |
|---|---|---|
| Prodrome | Mild / Absent | Severe (Cough, Coryza, Conjunctivitis) |
| Koplik's Spots | Absent | Present |
| Rash Confluence | Non-confluent | Confluent |
| Duration | 3 days | 5-6 days |
| Desquamation | None | Yes |
| Severity | Mild | Significant |
Risk by Gestational Age
| Timing of Maternal Infection | Risk of CRS |
|---|---|
| less than 12 weeks (First Trimester) | 85-90% risk of defects or fetal loss. |
| 13-16 weeks | ~35% risk. Usually deafness alone. |
| >16 weeks | Low risk. Deafness possible. |
| >20 weeks | Minimal risk. |
Classic Triad of CRS
| Defect | Notes |
|---|---|
| Cataracts | May be unilateral or bilateral. Present at birth. |
| Congenital Heart Defects | PDA (Most common), Pulmonary artery stenosis, VSD. |
| Sensorineural Deafness | Most common single defect. May be only manifestation if infection after 16 weeks. |
Extended CRS Features
| System | Manifestations |
|---|---|
| Eyes | Cataracts, Microphthalmia, Glaucoma, Retinopathy ("Salt and pepper"). |
| Cardiac | PDA, Pulmonary stenosis, VSD, ASD. |
| Hearing | Sensorineural deafness. |
| CNS | Microcephaly, Intellectual disability, Behavioural disorders, Meningoencephalitis. |
| Haematological | Thrombocytopenic purpura ("Blueberry muffin" rash), Haemolytic anaemia. |
| Other | Hepatosplenomegaly, Jaundice, Low birth weight, IUGR, Bone lesions. |
Late Manifestations of CRS
| Manifestation | Notes |
|---|---|
| Diabetes Mellitus | Increased risk in adulthood. |
| Thyroid Disorders | Autoimmune thyroiditis. |
| Progressive Rubella Panencephalitis | Rare. Neurological deterioration in second decade. |
Diagnosis (Postnatal Rubella)
| Test | Notes |
|---|---|
| Serology (IgM) | Rubella-specific IgM (Positive from rash onset to 6-8 weeks). Confirms recent infection. |
| Serology (IgG) | IgG seroconversion (4-fold rise in paired sera) confirms acute infection. Single positive IgG indicates past infection or vaccination. |
| PCR | Rubella RNA from throat swab, Urine, Blood. Useful in early infection. |
Diagnosis (CRS / In Pregnancy)
| Test | Notes |
|---|---|
| Maternal Serology | IgM positive or IgG seroconversion = Recent infection. If IgG positive only and high avidity = Past infection (Reassuring). |
| Fetal Diagnosis | Rubella PCR on amniotic fluid (Amniocentesis after 15 weeks). Fetal blood (Cordocentesis) for IgM. |
| Infant Diagnosis (CRS) | Persistent rubella IgM in infant. Rubella PCR (Pharynx, Urine – Babies can shed virus for months). Clinical features. |
Management Algorithm
SUSPECTED RUBELLA
(Rash, Lymphadenopathy, Exposure history)
↓
CONFIRM DIAGNOSIS
- Rubella IgM serology
- OR Rubella PCR (Throat swab, Urine)
↓
NOTIFY PUBLIC HEALTH
(Rubella is a NOTIFIABLE DISEASE)
↓
POSTNATAL RUBELLA (Non-Pregnant)
┌──────────────────────────────────────────────────────────┐
│ SUPPORTIVE CARE │
│ - Rest │
│ - Fluids │
│ - Paracetamol for fever/Arthralgia │
│ - Self-limiting (3-5 days) │
│ │
│ ISOLATION: │
│ - Avoid contact with pregnant women │
│ - School exclusion for 5 days after rash onset │
└──────────────────────────────────────────────────────────┘
↓
RUBELLA IN PREGNANCY
┌──────────────────────────────────────────────────────────┐
│ URGENT REFERRAL TO OBSTETRIC/FETAL MEDICINE │
│ - Confirm diagnosis (Serology, IgM, Avidity) │
│ - Counselling on CRS risk (Based on gestation) │
│ - Fetal assessment (USS, Amniocentesis) │
│ - Discuss options (Including termination if less than 16 weeks) │
│ - Public Health notification │
└──────────────────────────────────────────────────────────┘
↓
CONGENITAL RUBELLA SYNDROME (CRS)
- Multidisciplinary team (Paediatrics, Cardiology, Ophthalmology,
Audiology, Developmental)
- Supportive/Corrective treatment (Cataract surgery, Cardiac surgery)
- Hearing aids/Cochlear implants
- Developmental support and early intervention
- Infection control (Infants shed virus for months – Isolate from
pregnant women)
Prevention (Key Strategy)
| Measure | Notes |
|---|---|
| MMR Vaccine | Live attenuated. Dose 1: 12-13 months. Dose 2: 3 years 4 months. Two doses = 99% protection. |
| Pre-Pregnancy Screening | Check rubella IgG status. Vaccinate susceptible women BEFORE pregnancy. Avoid pregnancy for 1 month post-vaccination. |
| Postpartum Vaccination | If seronegative in pregnancy, Vaccinate immediately postpartum (Before discharge). |
| Contact Tracing | Identify susceptible pregnant contacts. Serology. Immunoglobulin NOT effective for post-exposure prophylaxis. |
Postnatal Rubella
| Complication | Notes |
|---|---|
| Arthralgia / Arthritis | Common in adolescent/Adult females. Transient. |
| Thrombocytopenia | Rare. Self-limiting. |
| Encephalitis | Rare (~1 in 6000). Post-infectious. Recovery usually good. |
Congenital Rubella Syndrome
| Complication | Notes |
|---|---|
| CRS Features | As above (Cataracts, CHD, Deafness, etc.). |
| Late-Onset Diabetes | Increased risk. |
| Progressive Panencephalitis | Rare. Neurodegeneration in second decade. |
| Factor | Notes |
|---|---|
| Postnatal Rubella | Excellent. Self-limiting. Full recovery. |
| CRS | Depends on severity. Significant long-term morbidity. Lifelong support often needed. |
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Rubella in Pregnancy | PHE / UKHSA | Urgent serology confirmation. Counselling. Fetal assessment. Notification. |
| MMR Vaccination | JCVI / Green Book | Two doses. Universal immunisation. Pre-pregnancy screening. |
What is Rubella?
Rubella (German Measles) is a viral infection that causes a mild illness with a rash and swollen glands. In children, it is usually very mild and gets better on its own in a few days.
Why is it important?
The danger of rubella is if a pregnant woman catches it, especially in the first 3 months. The virus can seriously harm the developing baby, causing problems with the heart, eyes, hearing, and brain – called Congenital Rubella Syndrome.
What are the symptoms?
- Low-grade fever.
- Pink-red rash starting on the face and spreading down.
- Swollen glands behind the ears and at the back of the neck.
- Joint aches (Especially in women).
Many people have no symptoms at all.
How can it be prevented?
The MMR vaccine protects against Rubella. Two doses provide lifelong protection. It is important for:
- All children (At 12-13 months and again at 3-4 years).
- Women planning pregnancy who are not immune.
What if I'm pregnant and exposed to Rubella?
Contact your GP or midwife immediately. A blood test can check if you are immune. If you are not immune and have been exposed, you will be referred for specialist advice.
Primary Sources
- Public Health England. Rubella: the green book, chapter 28. 2013 (Updated 2019).
- Banatvala JE, et al. Rubella. Lancet. 2004;363(9415):1127-1137. PMID: 15064032.
- World Health Organization. Rubella vaccines: WHO position paper. Wkly Epidemiol Rec. 2020;95(27):306-324.
Common Exam Questions
- Classic Lymphadenopathy: "Which lymph nodes are characteristically enlarged in Rubella?"
- Answer: Posterior Cervical, Suboccipital, Post-auricular.
- CRS Triad: "What is the classic triad of Congenital Rubella Syndrome?"
- Answer: Cataracts, Congenital Heart Defects (PDA), Sensorineural Deafness.
- Highest Risk Gestation: "At what stage of pregnancy is rubella infection most likely to cause CRS?"
- Answer: First Trimester (less than 12 weeks) – 85-90% risk.
- Prevention: "How is Rubella prevented?"
- Answer: MMR Vaccination (Two doses).
Viva Points
- Three-Day Measles: Rubella rash lasts ~3 days (vs Measles ~5-6 days).
- Notifiable Disease: Report to Public Health.
- Vaccine Timing in Pregnancy: Do NOT vaccinate in pregnancy. Vaccinate postpartum if seronegative. Avoid pregnancy for 1 month post-vaccination.
- Blueberry Muffin Baby: Thrombocytopenic purpura in CRS.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.