Yellow hair in a 2-year-old child may be caused by genetic factors, or it may be triggered by malnutrition, zinc deficiency and other factors. 1. Genetic factors, if someone in the family has yellow hair color, affected by genetic factors, the child may also appear this symptom. 2. Malnutrition, if you often do not pay attention to the child’s diet, malnutrition, partiality and picky eating, the body lacks zinc, may lead to hair growth is affected, hair yellow symptoms. 3. Improper care, if you usually do not do a good job of hair care, often use poor quality shampoo, may also lead to hair yellow. 2-year-old child hair yellow may also have other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, give targeted treatment or treatment.