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.
Many people associate allergies with dark circles. This is a real and established connection. In fact, many doctors consider dark circles as an indication of allergies in children. Allergies cause dark circles in two ways: first, histamine reactions themselves can cause dark smudges to appear under the eyes. The biology of this is way too complicated to get into here.