Are these bruises excessive in a sporty active 12 year old?

[pharmachameleon]

My 12 year old DS is super active, sporty but clumsy and often has bruises on his legs. He was at scout camp this weekend and when he was going into the bath tonight I was shocked with the state of his legs. They are completely covered in bruises but they are a reddish colour too. Should I be worried? They are only on the bottom of his legs and nowhere else on his body.
I'm trying to put the thought out of my head and not think about awful blood diseases. Anyone else have a child with so many bruises? I should add he's blonde and really pale usually.

@OneFrenchEgg Oh that is interesting. When I read up on it it said there was no traetment.
What treatment do you receive?

@antelopevalley we all have prescriptions for medication for if we have an injury - it's to be used in response and we have packs at school and home.
Also preventative meds - so before minor things like teeth extractions or mole removal we inform the clinic and they agree a treatment plan.
We have medical alert cards so that for anything more serious we have more intense medication (DVAP??) which you have to have a trial for.
There's quite a bit thinking about it, mainly to prevent a quiet but significant bleed continuing I suspect.

I bet he's doing something in particular that is causing them.
My daughter used to get loads of bruises on her leg when she pushed her bike and the pedals used to crash into her shins.

@OneFrenchEgg Thanks for replying. I just bled lots as a child when I had an injury. But it is much better now I am an adult so I will leave it. Luckily my children seem fine.

@antelopevalley no worries - I was more concerned about my dd as I lost a lot of blood during child birth and I didn't want that risk unchecked for her. Plus we suspect that older generations may have been taking inappropriate medication (undiagnosed) which didn't help.