Potty training regression

I ahve a 4 year old son who has been fully potty trained for two whole years. He has never pooped or peed in his pants since then. However, about three weeks ago, he started resisting going poop and has begun soiling his pants on an almost daily basis. It is usually not a big load, just little bits. He avoids answering why he is doing this. Today he is telling me it hurts when he poops. Everytime he has had an accident in his undies, it is poop that smells like moth balls. Not a usual poop smell. Other than that, his poops are normal in size, color, and smell. Now he has begun running away from me if I suspect he has had an accident and reisits me changing his pants. What could be going on???? I am VERY concerned! Please help.

[DustyL]

Google "encopresis" it sounds VERY MUCH like encopresis and is easily treated =] Good luck!

[cedarsong]

Thanks for the advice. I have looked into encopresis, but my child is still pooping on a daily basis, and the poops are totally "normal" looking and smelling, and definitely not hard or too soft. I'm thinking it's emotional rather than physical. He does not strain or express any pain when he's pooping and he doesn't need to sit on the toilet for long periods of time. I asked again whether it hurt him to poop and he said "no". Still perplexed..........

[flantastic]

give him only lactose free dairy products and NO FRIED FOODS for one month.  Bet you will see some major changes.  Worked for my daughter (via gastro visit).  She went thru the exact same thing.  Once they take a 'painful poop' they are hesitant to poop again.  Then it backs up and causes pain.  Once we changed her diet we never had problems again.