NHS guidance Is my child too ill for school? It can be tricky deciding whether or not to keep your child off school, nursery or playgroup when they're unwell. There are government guidelines for schools and nurseries about managing specific infectious diseases at GOV.UK. These say when children should be kept off school and when they shouldn't. If you do keep your child at home, it's important to phone the school or nursery on the first day. Let them know that your child won't be in and give them the reason. If your child is well enough to go to school but has an infection that could be passed on, such as a cold sore or head lice, let their teacher know.