allergic shiners?

[MamaDuckling]

Trying to get to the bottom of what is causing my son's dark red under eye circles.... Seem to occur sporadically, they don't irritate him but certainly look like they should be sore. I have a pic, but would certainly out me (and him) if anyone recognised DS! Not been on this forum before, is it common to post pics?

My dd's allergic shiners are more of a bluey/purple tinge; like black eyes. She's had them since she was around 3yrs, she's now 18yrs!! These can be worse during allergy season. For her it's worse with mould spores (Autumn) She also has the white line across the tip of her nose, another classic allergy sign.
Unfortunately there's not much you can do about them.