Autism and loose stools

Hi, 

our son is 5 years old and just started receptionin September. We are having issues with him having the occasional loose stool at school and touching it and smearing on toilet walls at school. Due to this I’ve had to pick him up and take him home as school said they can’t cope. They said he has Diarrhea (he has only had one accident today but has to stay off for 48hours) He otherwise is dry at home and uses the toilet to have his bowels open. I’m worried that he will identify that because I picked him up (which he was very happy about) this may happen again. He wears pants at home and prior to today hadn’t had any accidents for a month. School now are demanding he attend in pull ups. Has anyone any advice/ experienced similar situations. It’s very hard to know how to manage the situation. 

Thanks. Lucy