Dark eye circles though very common can be very challenging to treat in some cases. There are many causes that range from skin pigmentation to nose allergies which can lead to blood vessels congestion under the eye.
Another common cause is loss of volume around the eye through aging. A hollow trough appears creates a shadowing and hence darkening under the eyes.
Treatment options include lasers to lighten the skin tone, dermal fillers to restore the loss of volume around the eyes.