Why do S&V chips make my head hot?

[BrownSuga]

When I eat S&V or pickled onion chips (crisps), my face gets hot and feels like I'm about to break into a sweat.

Is this weird? Or is it an allergic reaction to something specific in those products (doesn't happen when eating anything else)?

Or am I inhaling the bag too fast perhaps?

Do they have MSG (monosodium glutamate) in? Some people are sensitive to it. I've noticed it even in some of the "posh" brands of crisps. Kettle chips don't have it in.

Same thing happens to me if I eat Skittles or Opal Fruits (which are not called that anymore are they?) but I guess that is the food colouring.

Just checked the pack, and they do have MSG. But I figure I must eat other stuff with MSG and only these two things seem to affect me.

I think I've a packet of skittles in the cupboard, I will test the theory on these tonight!