My husband without CAH, gets dark circles under his eyes when he is getting sick or is sick. I said if we ever had kids I wish to God they would be the same way so I could tell just by looking at them. Sure enough, my daughter with CAH gets the same dark circles if she is getting sick. I think it also depends on the skin you have. It seems to me more Italian or Jewish people seem to have a tendency to get the dark circles. We are German and Polish.  So we have pretty fair skin. I don’t get dark circles unless I haven’t slept in days. My niece gets dark circles and the puffy eyes always. No CAH. So you never know.