When allergies strike, they trigger the production of chemicals called histamines, which inflame blood vessels, making them visible through the thin skin beneath your eyes. If you're not sure whether your dark undereye circles are caused by allergies or something else, try stretching the skin beneath your eyes gently with your fingers. If the color remains the same, your dark circles are probably caused by allergies. If your circles get even darker, aging or genetics is probably to blame.
Ask your doctor to recommend a prescription or over-the-counter antihistamine medication for your allergies, and take your medication as directed, recommends New Jersey ophthalmologist Robert Mirsky on the Cosmopolitan website.
Use your ring finger to lightly dab a small amount of 0.5-percent hydrocortisone cream below your eyes if they are itchy as well as dark-circled, recommends Cheryl M. Burgess, medical director at the Center for Dermatology and Dermatologic Surgery in Washington, D.C., on the Oprah.com website.
Cut two thin slices from a potato and put them over your eyes for about 10 minutes twice a week to lighten dark circles. Potatoes contain catecholase, an enzyme that has a mild bleaching effect on skin, explains makeup artist Shalini Vadhera on the Cosmopolitan website.
Wear broad-spectrum sunscreen every day to prevent sun damage that makes dark circles more noticeable.
Use a retinol eye cream at night to stimulate collagen production. Increasing under-eye collagen makes allergy-related blood vessel swelling less obvious.