Newborns with hard lumps on the left side of the neck are considered to be the presence of strabismus, lymphadenitis, sebaceous cysts and other diseases. 1. Strabismus, if there is a muscular strabismus, there will be a mass in the area of the sternocleidomastoid muscle, so there will be a hard lump on the left side of the neck of the newborn baby. 2. Lymphadenitis, clinical lymphadenitis, due to lymph node congestion and edema, may produce newborns with hard lumps on the left side of the neck. 3. sebaceous cysts, if the sebaceous glands secretion, sebaceous gland ducts blocked, resulting in sebaceous cysts, may appear newborn baby neck hard lumps on the left side of the symptom. There may be other reasons for the lumps on the left side of the neck of newborns, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.