Do you have flaky skin in your eyebrows? Sometimes no amount of moisturizing seems to keep it at bay.
One cause can be very simple. Plucking and waxing can dry the tender skin around the eyes, including your eyebrows. A swipe of Vaseline at night can stop what seems to be "dandruff of the eyebrows."
Another common cause can be a yeast infection. Yes, that's right, a yeast infection. Not the same as the one "down below", but irritated skin can develop a yeast infection and it can persist if not treated.
Luckily, there is a very simple fix to this problem as well. At any discount store, purchase a tube of Lotramin cream. Apply it to your eyebrows and surrounding skin daily for a week. Be sure to avoid your eyelids.