Dark eye circles are shadows created by how light falls on the hollow areas under the eyes. This dark appearance and skin hollowness are caused by:
Ageing Volume Loss
Volume loss under the eyes forms a "tear trough," a depression under the eye which creates a shadow. Although ageing is a primary cause, some people have them as a natural deformity from a young age.
This occurs with ageing as the body's ability to produce new collagen decreases, weakening the skin's support network.
Causes vascular problems and constricts the blood vessels. This results in poor circulation, making the blood vessels appear darker and more prominent.
Lack of sleep may create paler, more translucent skin, which illuminates the blood vessels under the eyes.
Caffeine and Alcohol
Excessive caffeine and alcohol will result in dehydration, causing blood vessels to become swollen.
Nasal congestion and allergies may lead to inflammation and enlargement of the under-eye blood vessels.