Exanthem 3: rubella
Rubella is a mild disease in childhood occurring in winter and spring.
• Prodrome: the incubation period is 14–21 days during which time the child may have a mild illness with low-grade fever.
• Exanthematous phase: maculopapular rash starting on the face, then spreading to cover the whole body, and lasting up to 5 days.
• Other features: suboccipital and post-auricular lymphadenopathy.
If there is a risk of a non-immune pregnant woman has been exposed to the child, then the diagnosis should be confirmed by serology.
• Prevention: immunization with MMR.
Very rarely children may develop arthritis, myocarditis, encephalitis, or thrombocytopenia. (When MMR vaccine uptake is reduced, remember foetal rubella syndrome if a non-immune mother is infected early in preg-nancy.)