Hello
You need to find out why he is soiling.
Some ideas.
It could be a behavioural thing. That might be because to poo hurts, so he doesn't commit to it, then his body forces it out.
It could be deeper than that, he wants control over something, anything, and so is controlling his poo to the point where he can't anymore.
The most likely cause is constipation, or a memory of constipation. That leads to soiling because of the constipation and behavioural issues as the child does all they can to avoid going to the toilet/anything to do with poo.
this shows the Bristol stool chart, which it will really help your GP if you have done this. Basically you and your boy have a long hard peer at his poo, and the chart, and have jolly and fun discussions all about how it looks. Keep a diary between now and the appointment.
All this might help his to feel engaged in this little problem, and make him feel in control and less afraid of the dr.
Maybe five him a clip chart and white coat and he can pretend it's a Nina and the nerones episiode?
If you are seeing squidgy, sticky poo in his pants, but then large stool in the loo, I can nearly promise you it is constipation. The gp may look at his bottom to check his anus doesn't have tiny fissures [tears] or piles - as the pain will make everything worse.
Likey outcomes are treating constipation with lactalose. This takes days to kick in, and you have to keep going and rememeber it everyday. It's a pita. You may need to go onto something like Movicol. which also takes days and is needed everyday.
My dd's consultant says it takes as long to reverse the issue, as it did to get there. SO my dd has the condition for nearly 4 years, so we are looking at 4 years to get better.
My advice is to ignore the behavioural worries for now. Lets see if he has constipation, and get it treated. As that resolves, you may find the behavioural stuff just melts away. If not then the two may be more entwined and there are heaps of ways of working passed that.
Our life with constipation involves the following. You may not have a constipated bot, but if you do this is what helps us.
:battling to get 1 litre of fluid into dd1 everyday
:using pure juices, undiluted. Big no-no at the dentist, but as her paed says, would you rather have tooth worries or agony pooing. I know my answer!
:movicol everyday, sometimes twice.
:5 portions of fruit & veg in their natural form. Not puree etc, she needs to whole fruit/veg to make it work.
:we watch fibre intake. Yes it should be high, but it should be matched with huge amounts of fluid to ensure the stool produced isn't mega.
:plenty of toilet time. My dd has no idea she needs a poo. SO I watch for signs. Shuddering, pale, grumpy, on edge, wired, anxious, pacing, hiding, sitting down suddenly, bad breath, loss of appetite. If I see any of that we spend 30 mins on the loo.
:Time on the loo. Books, snacks, toys, portable dvd....we have done it all. What works best of all is letting her squat on the loo seat, gravity works it's magic.
:chiropractor. She usually does 3-5 poo's ont he day she goes. No idea why or how, but there you are.
It may be he is not constipated at all, but at his age and with his behaviours I wouldn't be at all surprised.