There are many reasons for hair loss on girls' heads, and it is normal if there is a small amount of hair loss. If hair loss is serious, you can look at: 1, genetic gene. If parents lose their hair, it will also affect their children, which may cause hair loss on the girl's head. 2, often take birth control pills, birth control pills contain a lot of estrogen and progesterone, long-term use of birth control pills may lead to hair loss in girls. 3, long-term use of computers, computer radiation comparison will lead to abnormal head fat secretion and hair follicle blockage, resulting in hair loss. 4. Scalp seborrheic dermatitis is related to the increase of androgen secretion in the body. Abnormal endocrine leads to exuberant secretion of sebaceous glands in scalp, clogging pores and alopecia, which can be improved by using ketoconazole lotion. 5, malnutrition, due to various reasons, girls' nutrition is uneven, malnutrition, will also cause hair loss on the top of the head.