Aging - The skin under the eyes is thin and delicate to begin with. As we grow older, skin around the eyes becomes thinner making blood vessels more prominent, causing dark circles.
Genetics - Hereditary and genetics can also play a big role in the development and dominance of dark circles around the eyes.
Nutritional deficiency - Dark circle around the eyes can be due to poor nutrition. A healthy and nutritious diet filled with vitamins like A, C, K, E and nutrients can help to get rid of dark circles.
Sleep deprivation and tiredness - A lack of sleep or excessive tiredness results in pale skin, making blood under the skin become more visible and appear more blue or darker.
Smoking and drinking - Late night parties, smoking and drinking can play havoc with your skin and result in dark eye circles. Dark eye circles could be a sign of loss of water from the body (dehydration) due to excessive drinking and intake of caffeinated drinks.
Sun exposure - Increased exposure to the sun can draw pigmentation of the skin’s surface and create dark circles. Long sun exposure produces more melanin around eyes than usual, giving them a darker color. There are two main layers of skin, the outer layer of skin known as epidermis and inner layer known as dermis. When excess melanin is being made in the epidermis it appears brown, and when there is more than usual melanin in the dermis it looks blue or blue grey.
Hormonal changes - In women, the skin undergoes lots of changes during the phase of pregnancy and menstruation, causing darkening under the eyes.
Allergies - Any condition that causes the eyes to itch may contribute to darker circles due to rubbing or scratching the skin around them. Apart from that, some food allergies can also cause the area under the eyes to appear darker. In fact, dark circles in children often indicate allergy problems.