Dark circles under the eyes have several distinct causes, and the one driving yours determines what (if anything) will help. They fall into a few broad categories: visible blood vessels showing through thin skin, excess pigment in the skin itself, structural shadows from lost volume, and congestion from allergies or sinus issues. Most people have some combination of these, and genetics play a role in nearly all of them.
Why Under-Eye Skin Shows Everything
The skin beneath your eyes is among the thinnest anywhere on your body. Underneath that delicate layer sits a dense network of tiny blood vessels. Because there’s so little tissue between those vessels and the surface, any change in blood flow, pigmentation, or skin thickness becomes immediately visible. It’s the same reason a bruise on your eyelid looks far more dramatic than one on your thigh.
As you age, the skin around your eyes actually thickens slightly due to structural changes and fluid retention, but the supportive fat and collagen beneath it diminishes. The net effect is a hollowed appearance that casts shadows, making dark circles more prominent even if the skin itself hasn’t changed color at all.
Vascular Dark Circles
The most common type appears as a blue, purple, or pinkish hue beneath the lower eyelid. This happens when dilated blood vessels show through translucent skin. When you’re tired, stressed, or dehydrated, those capillaries widen further. In some cases they can even break, leaving behind traces of hemoglobin that degrade into darker pigments as the body reabsorbs them. This is the same process that turns a bruise from purple to yellowish-green, except under the eyes it happens on a much smaller, subtler scale.
People with lighter skin tones tend to notice vascular dark circles more because there’s less melanin masking the underlying color. If you press gently on the dark area and it temporarily fades, that’s a strong sign blood flow is the primary cause rather than pigmentation.
Pigment-Based Dark Circles
Some dark circles come from actual excess melanin deposited in the skin, producing a brownish hue rather than a blue or purple one. This type is more common in people with darker skin tones and often runs in families. Sun exposure worsens it, since UV light triggers melanin production in an area that’s already prone to hyperpigmentation.
Conditions like eczema or contact dermatitis around the eyes can also drive pigment changes. Chronic rubbing or scratching of itchy skin stimulates melanin production over time, a process called post-inflammatory hyperpigmentation. This is why allergies can cause dark circles through two separate pathways: congestion beneath the surface and pigment buildup from repeated rubbing.
Allergies and Sinus Congestion
If your dark circles worsen during allergy season, the explanation is surprisingly mechanical. When your immune system reacts to allergens, the moist lining inside your nose swells. That swelling slows blood flow through the veins around your sinuses, and those veins sit close to the surface right under your eyes. When they become congested and swell, the area looks darker and puffier. Doctors sometimes call these “allergic shiners.”
This type of dark circle often comes with other telltale signs: nasal congestion, sneezing, itchy eyes, or a visible crease across the lower nose from habitual upward rubbing. Treating the underlying allergy, whether seasonal or triggered by dust mites or pet dander, typically improves the circles noticeably.
Structural Shadows and Volume Loss
Not all dark circles involve color changes in the skin at all. A significant number are optical illusions created by shadows. As you age, the fat pads that cushion the area beneath your eyes shift and shrink. Meanwhile, the ligaments holding everything in place gradually weaken. One key structure, the tear trough ligament running from the inner corner of your eye down toward the cheekbone, loosens over time and allows the fat above it to descend. The result is a visible groove, sometimes called a tear trough deformity, that catches light and creates a shadow resembling a dark circle.
Bone loss in the upper jaw contributes too. The same way a deflating balloon develops creases, the gradual resorption of the underlying bone leaves the soft tissue with less structural support. This is why some people develop dark circles in their 40s or 50s even if they never had them before. The central portion of the retaining ligament beneath the eye is the weakest link, stretching more than the edges, which is why the hollowing often appears most pronounced directly below the pupil.
Sleep, Stress, and Lifestyle
Sleep deprivation genuinely makes dark circles worse, though it doesn’t create them from nothing. When you’re exhausted, your body produces more cortisol to keep you alert, and cortisol increases blood volume. That means more blood flowing through those tiny under-eye capillaries, making them more visible. Fatigue also makes your skin paler overall, which increases the contrast between your face and the darker area beneath your eyes.
Dehydration has a similar effect. When your body lacks water, the skin around your eyes (already thin and vulnerable) looks more sunken and dull, exaggerating shadows and making blood vessels more apparent. Alcohol and high-sodium diets can worsen things in the opposite direction, causing fluid retention that puffs up the under-eye area and creates shadows along the lower border of the swelling.
Smoking accelerates collagen breakdown and narrows blood vessels, both of which thin the under-eye skin and reduce its ability to mask what’s underneath. Screen time itself doesn’t cause dark circles directly, but the eye strain and disrupted sleep patterns that come with late-night screen use certainly contribute.
Genetics and Skin Tone
For many people, the primary cause is simply hereditary. If your parents had prominent dark circles, you likely inherited thinner under-eye skin, a deeper tear trough, or a tendency toward periorbital hyperpigmentation. Some families pass along under-eye hollowing that appears as early as the teenage years, well before aging plays any role.
Skin tone matters too, but not in a simple “more melanin equals more circles” way. Darker skin is more prone to the pigmentary (brown) type, while lighter skin more easily reveals the vascular (blue-purple) type. Both are equally common, just driven by different mechanisms.
Medical Conditions Worth Knowing About
In most cases, dark circles are a cosmetic concern rather than a medical one. But certain systemic conditions can cause or worsen them. Thyroid disease, particularly an overactive thyroid, can cause puffiness and changes around the eyes. Iron deficiency anemia reduces oxygen delivery to tissues, which can make the under-eye area appear darker. Hay fever and atopic dermatitis are among the more frequent medical contributors.
If your dark circles appeared suddenly, are accompanied by significant swelling, or look noticeably different on one side versus the other, those are reasons to have a doctor take a closer look. Gradual, symmetrical dark circles that have been present for years are almost always benign.
Treatment Options by Cause
Because different mechanisms produce different types of dark circles, no single treatment works for everyone. The first step is identifying which type you have. A quick test: look at the color. Brown suggests pigmentation. Blue or purple suggests visible blood vessels. If the darkness disappears when you pull the skin taut or look upward, it’s likely a shadow from volume loss.
For pigment-driven circles, topical ingredients that inhibit melanin production and consistent sunscreen use are the standard approach. Retinoids can help by increasing skin cell turnover. For vascular circles, cold compresses, adequate sleep, and managing allergies make the most immediate difference. Products containing caffeine can temporarily constrict blood vessels and reduce the appearance.
For structural hollowing, topical products have limited effect because the problem is beneath the skin, not in it. Hyaluronic acid fillers injected into the tear trough can restore volume and reduce shadowing. The American Academy of Ophthalmology notes that fillers work best for subtle contour defects where surgery would be excessive, but they’re not ideal for patients with very thin or inelastic skin, where the filler can actually make the area look worse. For more advanced hollowing with significant skin laxity, surgical options that reposition fat and tighten tissue provide longer-lasting results.