GPAtlas🧭 When to suspect
Suspect chickenpox in anyone with a brief prodrome of fever, malaise and headache (often minimal or absent in young children), followed by a characteristic, intensely itchy rash. The rash evolves through macules → papules → vesicles (the classic "dew drops on a rose petal") → crusts, appears in successive crops so that all stages coexist, and typically begins on the face and trunk before spreading, sparing the limbs relatively. A history of contact with chickenpox or shingles supports the diagnosis.
The diagnosis is usually straightforward; the real clinical skill is twofold – identify the three high-risk groups in whom varicella can be life-threatening (neonates, pregnant women and the immunocompromised), and recognise the serious complications (pneumonia, encephalitis, severe bacterial infection). Most healthy children need only supportive care.
Two system changes now frame every consultation: from 1 January 2026 the combined MMRV vaccine replaced MMR in the routine childhood schedule (doses at 12 and 18 months), so milder breakthrough disease in part-vaccinated children will become a more common presentation; and chickenpox became a notifiable disease in England in 2025.
| Stage | Features and timing |
|---|---|
| Incubation | 10–21 days from exposure (commonly 14–16 days). |
| Prodrome | 1–2 days of fever, malaise and headache – often minimal or absent in young children. |
| Rash | Macules → papules → vesicles → crusts, in crops so all stages coexist; starts on face/scalp and trunk, spreads centrally, sparser on the limbs; mucous membranes may be involved. |
| Infectious period | From 1–2 days before the rash until all lesions have crusted (usually ~5 days from onset; prolonged if immunosuppressed). |
| Return to school/work | Once all lesions have crusted over. |
Source: UKHSA Green Book (chapter 34) · UKHSA / NHS England (MMRV programme)
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