Rubella

rubella · German measles · three-day measles

A mild illness in the patient and a serious one for a fetus - the reason to make the diagnosis is the pregnant contact.

GPBand B

Red flags

Any contact with a pregnant woman - this is the reason the diagnosis matters, and it needs same-day action
Rubella in a pregnant patient - urgent obstetric and health protection discussion
Failure to notify - rubella is a notifiable disease
A purpuric rash, bruising or bleeding - post-infectious thrombocytopenia is a recognised complication
Severe headache, drowsiness or confusion - encephalitis is rare but described

Recognise

On light skin

Fine pink discrete macules and papules beginning on the face, in a child who is only mildly unwell, with tender lymph nodes behind the ears and at the back of the neck.

On brown and black skin

The rash is faint even in pale skin and may be genuinely invisible in brown and black skin, so the diagnosis rests far more heavily on the lymphadenopathy and the contact history. Palpate for the suboccipital and postauricular nodes, which are the most reliable tone-independent sign. Do not exclude rubella because you cannot see a rash in a child with tender nodes behind the ears and a relevant exposure.

In any skin tone

Tender suboccipital, postauricular and posterior cervical lymphadenopathy - often more striking than the rash
A mildly unwell patient - no significant prodrome, unlike measles
The rash is discrete and fades in about three days
Joint pain, particularly in adolescent girls and adult women
Immunisation and contact history, including any contact with a pregnant woman

Distribution

Begins on the face and spreads to the trunk and limbs over about 24 hours - faster than measles - and fades within about three days. Lesions stay discrete rather than becoming confluent.

Photographs

The rubella rash on the abdomen. Fine pink macules, far paler and less confluent than measles, over a background of normal skin. Rubella's r — The rubella rash on the abdomen. Fine pink macules, far **paler and less confluent than measles**, over a background of normal skin. Rubella's rash is faint even on light skin, so on brown and black skin it is frequently not seen at all and the diagnosis rests on the suboccipital and postauricular lymphadenopathy. The only openly licensed photograph found for this entry shows light skin. **That is a limitation of this page, not of the disease** - a darker-skin photograph is still being sought.
Fitzpatrick II (Fitzpatrick type estimated from the photograph, not stated by the source) · CDC Public Health Image Library #4514 · Wikimedia Commons - Rubella.jpg · Public domain

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Measles — Measles is much more unwell, with a three to four day prodrome and a confluent descending rash
Parvovirus B19 (slapped cheek disease) — Also mild with joint symptoms, and also matters in pregnancy; the facial appearance differs
Scarlet fever — Scarlet fever has a sandpaper texture, perioral pallor and a sore throat
Roseola infantum — Roseola's rash appears as the fever breaks in an infant, which rubella's does not

What to do in the ED

Isolate on arrival and notify the health protection team the same day on clinical suspicion - rubella is notifiable
Ask explicitly about contact with anyone pregnant, and act on the answer today rather than leaving it to the GP
Arrange oral fluid testing as directed by the health protection team; clinical diagnosis is unreliable and laboratory confirmation matters here
Check immunisation status and recommend MMR where indicated
Assess for thrombocytopenia if there is any purpura or bleeding
Advise exclusion from school or work for five days after the rash appears, and avoidance of pregnant contacts

Disposition

Supportive care at home with notification and exclusion advice. Pregnant patients and pregnant contacts need same-day obstetric and health protection input.

Safety-netting

Stay away from school, nursery or work for five days after the rash started, and keep away from anyone who is or might be pregnant. Tell us straight away if you have been near a pregnant woman. Return if bruising or bleeding appears, if there is a severe headache, or if the patient becomes drowsy or confused.

Sources

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