Skin that really swells up/reddens when bumped/scratched, then goes back to normal?

[Boboma]

My DD (4) has strange skin. Any slight knocks/bumps/rubs/scratches in any part of her body flare up with a really angry, raised rash. It looks like something awful has happened, but really quite quickly her skin goes back to normal. eg if we wash her face with a cloth she looks like she has fallen badly on her face - but only for 15 mins or so. She has some congenital conditions so this has always been the least of our worries, but she has just started school and the teacher was alarmed (I had forgotten to mention it). I don't think that it is anything to worry about, but I just wondered if anyone else's DCs have this and have any way of explaining it?

My DS is very similar! He was in the bath this evening and was scratching his leg and it looked like he'd been attacked! but had gone by the time he got out of the bath! he's always been very easy to mark, my skin is quite similar although not quite as bad. I don't really no why it occurs although i guess it has something to with the fact DS has quite sensitive skin and is also quite fair.
I can see why it panics others though!

My friends dd has something similar, in her case it's to do with too much histamine production. She also has urticaria which I think might be connected.

Its called dermographia iirc - my mum has it. If you gently run your fingernail along her leg you can write your name. It gets worse when her histamine levels are high

Thanks - I'm glad to hear that she's not the only one. Thanks for the name CMOTdibbler (always good when things have an impressive name!). I've just looked at it on wikipedia and that's it exactly. It also seems to be pretty common. At least I know a little more now to explain it.....

I have this. I can write my name on my arm with gentle fingernail pressure. It's gotten better as I've got older. Haven't noticed it in DD though.

My DH has this. He takes antihistamines every day to keep it at bay. Still though sometimes he can pull a t-shirt on and his face looks like he's been in a fight.