Dark circles (also known as dark circles or periorbital hyperpigmentation) are dark blemishes around the eyes. There are many causes of this symptom, including heredity and bruising. Any condition that causes the eyes to itch can contribute to darker circles due to rubbing or scratching the skin around them. Hay fever sufferers in particular will notice under-eye "smudges" during the height of the allergy season. Some food allergies can also cause the area under the eyes to appear darker.