For some weeks now Dory has blisters on both big toes. On the outer side, a very unusual spot for blisters. I checked and rechecked her shoes, they could not be the problem, she should have enough room for her toes. Nevertheless, we went to the children's shoe shop today. One of those recommended by podiatrists.
The shop assistant took a close look at Dory's toes and feet and agreed the shoes still fit. But some people can't endure the seams on the toes of socks and it is very likely this is causing the problem. And then she came up with the solution:
"Some children have to wear their socks inside out or hand knit socks." Yay!
We did buy a pair of boots anyway :)