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What your kids are having might be impetigo contagiosa
. It is a bacterial infection caused by Staphylococcus
and has a propensity to spread. One or two lesions can be managed with topical antibiotic
2% cream application 3 times a day. Avoid sharing of towels and clothes. An antiseptic soap containing triclosan will help. If it is extensive or not improving an antibiotic course covering staphylococcus will help and you need doctor's consultation and prescription for it.
Hope this helped.