Hi there

For some obscure reason all sports related clothing is synthetic fiber based.
Those terrible bike pants, for instance and the horrible sweatshirts with the big numbers on it. I wouldn't wear rubbish like that if it came with money attached. It stops the skin from breathing properly and causes heatrashes.
I think you should wear cottons or other natural fibers instead of plastics and see how you go.
Vitamin C helps overcome heatrash and will get rid of the skin irritations. 2000 mg daily would suffice.

Good luck

Kinetico

I agree that natural fibers would breathe much better. At the very least, you could wear a cotton barrier (like a long-sleeved t-shirt) between your skin and the equipment.

Do you share the equipment or is it just yours? Either way, make sure you clean the sweat off and make sure the equipment drys between uses. Does the rash go away when you haven't played in a little while, or is it always there now?

If it doesn't go away, you might want to see a doctor in case it is something he can treat. Does anyone else on the team have this?