Dark circles appear as discoloration below the eye. “This can either be due to hyperpigmentation of the skin, or thin skin that allows blood vessels and underlying tissue to show through,” explains board-certified dermatologist Rebecca Marcus, M.D., FAAD.
This discoloration is starkly different from eye bags in terms of cause and appearance. Eye bags are consistent outpourings of tissue below the eye that are, “Usually caused by fat herniation as the tissue becomes less firm with age,” Marcus says.
Dark circles are also different from general eye puffiness. “Puffy eyes usually refers to swelling around the entire eye, which may be a result of an allergy, dietary factors (salt, alcohol), illness, or other sources of inflammation,” Marcus says. Some of these same factors can lead to dark circles, too—more on that below.