Apart from lack of good sleep and fatigue, there are some other common causes of dark circles under eyes. They include physical causes, genetic causes and aftermath/symptoms of certain medical condition
Other causes of dark circles under eyes are;
Heredity: Dark circles under the eyes may run within the family. That is why it also occurs in children because it can be inherited
Allergies: Nasal allergies can affect the areas under the eyes and make it appear darken.
Excess Sun Exposure: This may cause the skin to produce excess melanin (pigment responsible for skin color)
Iron deficiency causing insufficient oxygen-rich blood from getting to the eyes tissue
Aging : This can result to thinning of the skin, loss of fat and reduced collagen and hence making dark circles under the eyes more obvious.
Rubbing or scratching of the eyes
Atopic Dematitis (Ezcema)
Fluid Retention as a result of weight gain, pregnancy or excess salt intake
Lifestyles such as excessive smoking, drinking and over-stressing
Too much sleep and lack of sleep can both result in dark circles under the eyes