Eyes that look youthful, beautiful, and well-rested make the face aesthetically appealing. Such eyes are decisive in shaping one’s personality while eyes having dark circles underneath may play a spoilsport. [1, 2]
What are Dark Circles under the Eyes?
Dark circles under the eyes, medically termed periorbital dark circles, refer to the area of the skin beneath the eyes which appears darker than the surrounding skin. They are easily noticed on the face because the skin around the eyes is thinnest among the skin of all other body parts which makes the underlying blood vessels show up. The under-eye area may look dark in different shades like blue, purple, brown, or black, depending upon one’s natural skin color. These dark circles make the eyes look fatigued and old than they are.
Dark circles are usually not considered to be a medical problem but rather an aesthetic dermatologist concern. They can affect anyone irrespective of age, sex, or race. However, dark circles under the eyes are mostly found in aged people, individuals with darker skin tones, and those who have a family history of under-eye dark circles. Sometimes, good rest and proper sleep can be a remedy for this unwanted problem. [1, 3]
Causes of Dark Circles Under the Eyes
Researchers have found many causative factors behind those shadowy half-moons. Here are the common ones:
1. Aging and Thinning Skin
As one gets older, the thin skin under the eyes becomes thinner as the skin stops producing enough collagen- the skin’s structural protein. This makes the numerous dark blood vessels passing through the under-eye area more obvious and appear as dark circles. When there is any clotting in these vessels, the skin overlying it turns into a blue-black tinged region. Furthermore, aging could also cause the hollowed areas or tea troughs to develop that have shadow-effect on the under-eye region, hence giving an appearance of dark circles. [1, 2, 3]
If one is suffering from any seasonal allergies or hay fever, there is triggered histamine release in the body. Histamines are the chemicals produced by the immune system to help the body get rid of any allergens or foreign substances that have entered the body through a wound or any opening of the body. They lead to allergic reactions that are accompanied by an itchy feeling. Subsequent rubbing and scratching of the skin can result in swelling and breaking of the blood vessels present in the under-eye area. If that happens, the skin overlying these blood vessels may appear darker than the rest of the face. [1, 2]
3. Genetic Predisposition
Sometimes, bad genes can turn out to be the culprit of dark circles. Some studies have shown that dark circles concern can run in family, it’s a hereditary factor. In some families, the members may have dark-pigmented under-eye region and rest all normal skin or they may be dark-skinned with a higher risk of developing dark circles, or else they have deep-set eyes which makes the dark circles more noticeable. 
4. Lack of Sleep
Anyone having poor sleeping habits would have pale skin under the eyes and the blood vessels in that region could become prominent. This would give a tired look to the eyes, the appearance of dark circles. 
5. Bad Lifestyle Choices
Smokers and alcohol abusers are more likely to have under eye dark circles. This is because they have disrupted sleep patterns which can result in the collection of fluids beneath the eyes, thereby causing or exacerbating the appearance of dark circles. Excessive drinking of alcohol causes dilation of the blood vessels under the eyes which makes dark circles show up. Smoking tobacco can even break the collagen and elastin of the skin, thus making dark circles prominent. 
6. Menstruation and Pregnancy
At the time of pregnancy or menstruation, women experience hormonal fluctuations which in turn significantly affect their skin. One such effect is seen under the eyes as dark circles because of hyperpigmentation. 
7. Long or Frequent Sun Exposure
Sun exposure can increase the production of melanin (the flesh-colored pigment) by the melanocytes. Moreover, too much UV exposure from the sunlight encourages the breakdown of collagen. Fewer collagen results in thinner skin which eventually makes the blood vessels more obvious. In both cases, a darker shade of the skin beneath the eyes appears. 
8. Too Much Stress
Dark circles can also reflect one’s stress. When one’s body is stressed, the blood flow to the face gets affected resulting in no normal flushing to the face. The lack of blood supply causes the skin under the eyes to appear pale and blood vessels to become more noticeable, hence giving the appearance of dark circles. 
People who don’t drink enough water daily would have dull-looking skin and their eyes would appear sunken. As a result, the under-eye region would have pronounced blood vessels and shadow effects. [1, 3]
10. Skin Concerns
Contact Dermatitis and Eczema are two skin issues that can cause the under-eye blood vessels to dilate and dark circles to easily show up. 
11. Certain Diseases
Researchers believe that anemia or liver diseases can cause dark circles to appear under the eyes. 
12. Nutritional Deficiency
Those who are not taking all nutrients to keep skin healthy in their daily diet are likely to develop dark circles. The body must have adequate levels of Vitamins A, C, E, and K to prevent dark circles.
Ways to Deal with Dark Circles Under the Eyes
- Make Changes to Diet- Pick food items containing more antioxidant pigments that help keep the blood vessels stronger; limit the intake of salty food as it could cause puffiness; hydrate the body with fresh fruit juices, water, and electrolyte-rich fluids.
- Protect the Peepers- Take proper sleep at night; stay away from sun exposure or wear sunscreens, sunglasses, and large hats for sun protection when outside; don’t rub the eyes too much.
- Pamper the Under-Eye Skin- Try black tea bags, slices of cucumber, or skin creams and serums like those containing Vitamin K that could reduce under-eye dark circles.