Hi. My son had them and yes they are contagious and caused by a Staph infection.  See your GP.

Heres some advice to look at

:www.minti.com/parenting-advice/5199/ImpetigoCommonly-known-as-school

just to add a little more on already the great information that is already here ..

you will also have to wash the bed sheets etc,, as its contageous ( just like you would wash everything when your child has nits)

Cazza has said it all if it's school sores. If it turns out not to be, one of the best ointments for any sort of rashes (is magic on nappy rash) is paw paw ointment. It's great for rashes, insect bites, sores - just about anything! It's available in supermarkets & pharmacies in tubes or jars. It's also good value as you only need use small amounts so it lasts a long time.

If your child has school sores you  need to have it checked by a doctor to be sure that it is school sores, because an antibiotic medicine or sometimes ointment is generally prescribed.

If an antibiotic ointment is recommended, the sore needs to be washed and the crusts lifted gently off for the ointment to work best.

Try to prevent the child from scratching of the sores as much as possible, eg cover sores with a watertight dressing and cut the childs fingernails.

Using an antiseptic soap may help stop spread of the infection to other parts of the body.Also if a child has School sores they need to be kept home after 24 hours of having  treatment and make sure they have their own face washer and towel, and have them washed them separate...

take care
love cazza