UTI in 2yr old?

[Trishalynn]

my dd is grabbing herself down there and crying owww every time she pee's she does have a little diaper rash, nothing bad at all only a slight one. So how would you tell if its a UTI? She's only been doing this today for the past couple of hours so I don't know if the rash was actually bothering her that much or if its an infection? are there other signs to watch for? she's not potty trained yet. thanks!