Here is a link with skin conditions common in children:
http://www.babycentre.co.uk/l1038755/childhood-rashes-skin-conditions-and-infections-photos
And here's another link stating the different types of rashes and suggestions on how to treat them:
http://www.parents.com/baby/health/rashes/rashes/
In general, rashes can be treated locally with antiseptic or antibacterial treatment. Contact your doctor if the rash is accompanied with fever, headache or sore throat.