The common causes of spots on the chest are: i. If the skin on the chest area is infected by fungus to form lichen planus, untimely treatment or the use of hormone-containing food during the treatment process leads to skin pigmentation to form patches. Second, the chest area is exposed to allergic substances causing allergic dermatitis, and long-term use of glucocorticoid products also tend to form plaques. Third, after women enter puberty, the normal metabolism of the chest skin is affected by the level of estrogen in the body, which is also prone to chest plaques. If one of the parents has long spots on the chest, the chances of their children having long spots on the chest will also increase. If there is pigmentation on the chest with obvious itchy skin, it is considered to be caused by pathological factors, and it is necessary to go to the dermatology department of the hospital for consultation in time.