Under-eye dark circles, sometimes called under-eye shadows, are usually caused by conditions or genetic factors that make it easier to see the blood vessels under the skin around the eyes. In some cases, the skin around a person's eyes is very thin or pale, which makes the blood vessels underneath much more obvious. In other cases, the dark circles are more apparent because a person is tired, dehydrated, or suffering from allergies. In some cases, they can also be a sign of fluid retention caused by dietary choices, though they may also be a symptom of a more serious medical condition that causes a person to retain fluid. Another possible cause of under-eye shadows is anemia.
While frustrating, dark circles under the eyes are generally not a symptom of a serious medical condition. In many cases, people are born with a tendency toward under-eye discoloration, either because of their skin's texture or because their skin is highly pigmented in certain areas. Further damage to the skin from sun exposure can also contribute to the appearance of dark circles under the eyes. Age also plays a part in under-eye discoloration, as fat under the skin decreases as the skin itself thins and deteriorates, making it easier to see the blood vessels underneath the eyes.
Dark circles can be exacerbated by various lifestyle choices. One of the best-known contributors to dark circles is a lack of sleep, which contributes to facial paleness, making under-eye shadows more pronounced. Allergies may cause sufferers to rub at their eyes, which can irritate blood vessels and make them more prominent. Smoking or certain dietary habits can also lead to fluid retention, which may likewise make the blood vessels under the eyes more noticeable.
In some cases, dark circles can be a sign of a more serious condition. Anemia, a condition of low iron in the blood, can result in dark circles, as can water retention caused by kidney problems. Individuals who suffer from under-eye discoloration that doesn't go away after the implementation of a better sleep schedule, the treatment of allergies, or other lifestyle changes should consult a medical professional, particularly if they have other symptoms that point to ill health. Health care professionals can assess the situation and take tests to rule out an underlying health problem. In some cases, cosmetic treatments may be available to help the patient improve his appearance.