On the first day a rash appears as small red patches about 3-4cm across. Within a few hours of these developing, small blisters appear in the centre of these patches.

During the next 3 or 4 days further patches will appear and the earlier ones will turn "crusty" and fall off.

Oily Calamine Lotion may be applied to soothe the often severe itching. Cool baths may also help. The most infectious period is from 2 to 3 days before the rash appears and up to 5 days after this date.

Children may return to school as soon as the last "crusts" have dropped off.