Rubella in Children
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Direct answer
Rubella is a mild, usually self-limiting viral exanthem caused by the rubella virus, and it matters chiefly because infection in early pregnancy can cause congenital rubella syndrome. It presents with a fine pink maculopapular rash that spreads from face to trunk, low-grade fever and tender postauricular and suboccipital lymphadenopathy. The measles-rubella vaccine is the main preventive measure.
What you must remember
- Causative agent: rubella virus, an RNA virus spread by respiratory droplets.
- Incubation: about 14 to 21 days, and the child is infectious from about a week before the rash until about a week after it appears.
- Prodrome: low-grade fever, malaise and sore throat, often mild or absent in children.
- Lymphadenopathy: postauricular, suboccipital and posterior cervical nodes, often tender, are the classic clue.
- Rash: a fine pink maculopapular rash that starts on the face, spreads to the trunk and limbs, and clears in about three days.
- Forchheimer spots: petechiae on the soft palate are described in rubella.
- Congenital rubella syndrome: cataract, sensorineural deafness and patent ductus arteriosus, with the highest risk in the first trimester.
- Prevention: measles-rubella vaccine in the national immunisation programme.
Rubella and measles at the bedside
Both diseases give a rash and fever, so the examiner expects the features that separate them. Many children with rubella are missed because the illness is mild, so a careful look at the lymph nodes and the rash history matters. The table sets out the key differences in a child who presents with a rash.
| Feature | Rubella | Measles |
|---|---|---|
| Causative agent | Rubella virus | Measles virus |
| Prodrome | Mild, often absent in children | Cough, coryza and conjunctivitis |
| Lymphadenopathy | Prominent postauricular and suboccipital nodes | Less prominent |
| Koplik spots | Absent | Present on the buccal mucosa |
| Rash course | Pale pink, clears in about three days | Dusky red, spreads from behind the ears, leaves brownish staining |
| Key complication | Congenital rubella syndrome | Pneumonia, encephalitis and subacute sclerosing panencephalitis |
Postauricular lymph node enlargement and a fast-clearing pink rash point to rubella. Koplik spots, a cough and a longer, brownish-staining rash point to measles, and this difference matters for notification and for infection control. A mild rubella case can resemble other viral rashes in an unvaccinated child, so the history of vaccination and contacts should be taken with care.
Where the exam tries to catch you
Questions on this topic test the lymph nodes, the rash and the risk in pregnancy.
- Trap: labelling Koplik spots as a feature of rubella Correct: Koplik spots are seen on the buccal mucosa in measles, and rubella does not produce them.
- Trap: dismissing rubella as harmless because it is mild in children Correct: its real importance lies in congenital rubella syndrome after infection in early pregnancy.
- Trap: describing the rubella rash as itchy and vesicular Correct: it is a fine, usually non-itchy, pink maculopapular rash that clears in about three days.
- Trap: reassuring a pregnant contact who has no history of rubella Correct: a non-immune pregnant woman exposed to rubella needs serological testing rather than reassurance.
Frequently asked questions
Which lymph nodes are enlarged in rubella?
Rubella typically enlarges postauricular, suboccipital and posterior cervical lymph nodes, which are often tender. Postauricular enlargement is the classic finding that helps distinguish rubella from measles at the bedside. Lymphadenopathy often appears before the rash.
How does the rash of rubella differ from the rash of measles?
The rubella rash is pale pink, fine and maculopapular, starting on the face and spreading to the trunk. It clears within about three days. The measles rash is dusky red, starts behind the ears and lasts longer, leaving brownish staining.
What are the features of congenital rubella syndrome?
Congenital rubella syndrome classically causes cataract, sensorineural deafness and patent ductus arteriosus. The risk is highest when the mother is infected in the first trimester. Other features include intrauterine growth restriction, microcephaly and hepatosplenomegaly.
Why is rubella infection in early pregnancy so important?
Rubella infection in early pregnancy can damage the developing fetus and cause congenital rubella syndrome. The risk is highest in the first trimester and falls later in pregnancy. A non-immune pregnant woman exposed to rubella needs serological testing and specialist advice.
What is the main preventive measure against rubella in India?
Measles-rubella vaccination is the main preventive measure against rubella in India. It is given as part of the national immunisation programme and protects against both diseases. Community immunity also protects pregnant women who cannot be vaccinated.