A cold shower and a cup of coffee may help you mentally recover from a sleepless night, but the telltale circles under your eyes announce to the world that you're feeling tired. Whether they're faint purple shadows or dark blue smudges, undereye circles make you look exhausted--and may also make you look older than you really are.
You may notice smudges and shadows under your eyes in the morning or at the end of a long day, but doctors define dark circles as uniform, round areas of darker pigmentation that appear under both of your eyes, according to the Mayo Clinic. Though the Mayo Clinic says they're most common in adults, children can get dark circles, too.
When you're tired, your skin can get dull and dehydrated, causing hollow areas below your eyes and allowing dark blood vessels and tissue beneath your skin to show through, according to the New York Times. The thin, delicate skin around your eyes may be especially susceptible. Sleeplessness can also cause fluids to accumulate around your eyelids, puffing them up so that they cast dark shadows onto the area under your eyes, according to the Mayo Clinic.
If lack of sleep is an ongoing problem, talk with your health-care provider so you can look for a solution. If your dark circles are just an occasional problem, Jeannette Graf, an associate clinical professor of dermatology at the Mount Sinai School of Medicine in New York City, recommends in "Real Simple" magazine that you use a cold compress when you wake up to soothe puffiness and follow up with an eye cream that contains caffeine, which will constrict blood vessels so they're less noticeable. Use a retinol cream at night to stimulate collagen production to prevent thinning skin.
If you had a sleepless night and need to hide your dark circles fast, "Allure" magazine suggests opting for an emollient concealer that's an exact match for your skin color--don't go a shade lighter--and applying it on top of a light-diffusing eye cream.
Though lack of sleep can cause or exacerbate dark circles, sleeplessness isn't the most common cause of dark circles. If you regularly get enough sleep and still have dark circles, your over-pigmented eyes may be caused by allergies, eczema, nasal congestion, irregular pigmentation or genetics. Treatments for dark circles are similar whatever their cause, but consider seeing a dermatologist if you're not sure what's causing your dark circles. You should also see a dermatologist if your dark circles are under only one of your eyes.