Playground teasing - help, please

[strugglingsocially]

DD's special need is not being able to cope with playground teasing. She is 10, will be 11 next month. She has always been sociable but, perhaps because she's a virtual only child (older siblings grown up by the time she was born), has great difficulty coping in a crowd. Perhaps this makes her a little possessive of her best friend.

She's also 'different', in the sense that she's surrounded by girly girls but is more the active, sporty kind herself. She's a scout where all the others are girl guides, and so forth. She thinks the girls in her class fuss about trivia.

The present problem is that a boy who is about eighteen months younger than her is teasing her at school and it's getting her down. I'm very good friends with his mum and he's fundamentally a nice kid but, if what DD tells me is true, has found her weak spot and is getting at her in the way, perhaps that a younger sibling might.

I don't know what to do.