Can't you just wear a hypo-allergenic balaclava under the helmet of your choice?
Nope. It's not just what I touch, it's what I breathe. I have had to have all my zippers in trousers made from metal, all the buttons in all my clothing made from natural materials (bone, shells, wood), all tags removed, no elastic anywhere etc.
Try finding non-elasticated socks without elasthan or nylon or other chemical compound. It's practically impossible, but it is to that extent I have to go.
A silk balaclava would do nothing for me after a couple of minutes or so when it got warm. Then it would have soaked up the chemical crappola from the helmet, and then I'm back at square one.
If only it were my skin like when people had nickel allergies. That would be easy to live with.
