Rubella (German measles)
Introduction
Rubella is a generally mild viral exanthem caused by the rubella virus (a togavirus). Endemic rubella is now uncommon in the UK because of widespread MMR immunisation, but sporadic cases and small outbreaks still occur. Prompt recognition in the emergency department has important clinical and public‑health implications, particularly for pregnant women and their contacts (Green Book; GOV.UK).
At a glance
- Aetiology: rubella virus (togavirus).
- Incubation: 14-21 days (most rashes occur 14-17 days after exposure).
- Infectious period: approximately 7 days before symptoms to 4 days after rash onset.
- Rash: pink maculopapular eruption beginning on the face/behind the ears and rapidly generalising; typically lasts 1-5 days and fades by day 3-5.
- Lymphadenopathy: tender posterior auricular and suboccipital nodes are characteristic.
- Complications: rare (immune thrombocytopenia, post‑infectious encephalitis); adults commonly have transient arthralgia/arthritis.
- Pregnancy risk: highest in the first 8-10 weeks of gestation (risk of major fetal damage in surviving infants up to ~90%); risk declines thereafter and is uncommon after 16 weeks, although sensorineural deafness may occur with later infections.
- Exclusion: avoid school/childcare until 5 days after rash onset.
- Notification: notifiable disease-notify local Health Protection Team/UKHSA on clinical suspicion (do not wait for laboratory confirmation) (Green Book; GOV.UK).
Clinical features
Children often have a mild or absent prodrome (low‑grade fever, coryza, conjunctivitis); adults more commonly develop systemic symptoms and...