What is the etiology and pathogenesis of hair loss in young people?

1, alopecia caused by endocrine disorders. Hair growth is influenced by a variety of endocrine hormones, so when the endocrine is abnormal, it will often cause hair loss diseases, and androgenetic alopecia is also the most common type of hair loss in men, mainly due to the high level of androgen in the human body. 2. Neurogenic alopecia. Under the action of mental stress, the human hair muscles contract, the hair stands upright, the autonomic nerve or central nervous system function is disordered, the papillae of hair follicle is greatly changed, and malnutrition leads to the inhibition of hair growth function, the hair enters a static stage, and hair loss occurs. 3. Nutritional alopecia. Hair is an external manifestation of physical condition. Malnutrition and abnormal metabolism will cause changes in hair quality and hair color, severe malnutrition and even diffuse alopecia. 4, physical hair loss. Common physical factors leading to hair loss include mechanical stimulation and exposure to radioactive substances. 5, chemical hair loss. Chemical factors can lead to hair discoloration and even hair loss. Common things, such as unreasonable hair dyeing and hair loss caused by chemicals intake. 6, infectious alopecia. The infection of various pathogens is the main factor of hair diseases, mainly including the damage of hair papilla caused by head infections such as bacteria, viruses, fungi, spirochetes and parasites. 7. Symptomatic alopecia. Some systemic or local diseases may be accompanied by alopecia. For example, women have hair loss symptoms after giving birth to a baby. Common and hypothyroidism, often seen dry hair, dry skin, increased sensitivity to cold, accompanied by narcolepsy,