The darkening and bluing under the child’s eyes may be caused by physiological factors such as thin skin and lack of sleep, or it may be caused by factors such as post-inflammatory hyperpigmentation. 1. Physiological factors: the skin under the child’s eyes is relatively thin and tender, localized veins, blood through, will be manifested in the local skin black and blue phenomenon. Secondly, if the child does not have enough sleep, it will also lead to black and blue skin. 2. Post-inflammatory hyperpigmentation: If the child’s eyes are suffering from allergic dermatitis or eczema and other diseases, when the disease subsides, the local melanin precipitation phenomenon may occur, which is also manifested as black and blue. There are many reasons why children’s eyes are black and blue, they should be examined in time, cooperate with the doctor’s treatment, to avoid jeopardizing the health of the skin.