Can A Penis Discharge Be An Infection?

I've noticed (for three days now) small white circles (I assume from some type of discharge) in the underwear of my 4 1/2 year old son. He CONSTANTLY plays with his penis now that he doesn't wear diapers....He is Autistic and not very verbal so I can't find out if it hurts or is itchy at all. is this normal or could it be signs of infection?