Periorbital hyperpigmentation (POH), or periorbital melanosis, is a benign and very common dermatological condition that is characterized by dark circles located around the eyes, most often seen on the inferior eyelids. POH is present nearly equally in males and females but may affect more women due to hormonal influences. It is seen more frequently in individuals with darker skin phototypes, and it tends to worsen with age.

Many endogenous and exogenous factors can contribute to POH including genetics, postinflammatory hyperpigmentation (allergies, periorbital eczema), drug-related causes (vasodilatory medications, glaucoma medications such as latanoprost, hormonal therapy), procedures (blepharoplasty, rhinoplasty, chemical peels), and environmental / lifestyle changes (sun exposure, lack of sleep, stress, alcohol, caffeine, smoking).

The underlying pathogenetic mechanisms can be summarized as follows: increased melanocyte or melanophage density or increased melanin production; changes in vasculature; or mechanical changes in skin laxity, muscle, or tear trough that contribute to shadowing effect.