Dark circles and bags under eyes can make you look older than you are. Dark circles are a common problem faced by both men and women. Compared to other parts of the body the skin around our eyes is very thin and extremely delicate. And so any changes in the deeper layers of the skin will appear on the surface. Dark circles under your eyes are most commonly caused by fatigue. But there are other causes too and these include allergies allergic rhinitis (hay fever) atopic dermatitis (eczema) contact dermatitis genetics pigmentation irregularities scratching or rubbing eyes and sun exposure.