Cancer cells divide more quickly than healthy cells, and chemotherapy drugs effectively target those cells. Unfortunately, fast-growing cells that are healthy can be damaged too. There are many different chemotherapy drugs with the potential for many different side effects.
Symptoms & Signs. Dark circles under the eyes are a common complaint of both men and women, although they can occasionally be seen in children. As people age, the skin becomes thinner and collagen is lost, sometimes enhancing the appearance of blood vessels beneath the eyes and making the area appear darker.
Allergies Causing Dark Under Eye Circles. Dark circles under the eyes, when related to nasal allergies, are called allergic shiners. Allergic shiners are related to nasal congestion, which can occur for other reasons besides allergies, such as with the common cold or with sinus infections. These dark circles under the eyes are a major concern for many people, as it makes them look tired and unhealthy.