In the first case, it occurs in infants and young children or in women with fair skin, mainly due to subcutaneous venous manifestation, which is manifested as nasal cyanosis. In the second case, the patient has subcutaneous bruising due to trauma to the nose, and the subcutaneous veins are dilated to show a blue nose. In this case, you can do local hot compresses to promote blood circulation, after a period of time, the local bruising will be absorbed on its own. In the third case, which is more common in young infants, it may be accompanied by labored breathing and difficulty in breathing, in addition to a blue nose. In this case, it is necessary to go to the pediatric department to improve the cardiac examination to exclude any congenital heart disease, resulting in ischemia, hypoxia and other related manifestations.