1. Androgenetic alopecia, also known as seborrheic alopecia or male pattern baldness, mainly occurs between the ages of 20 and 50, with changes in the pace of life and work pressure, the incidence rate is gradually increasing and showing a trend of low age, with young people becoming the main force of the “hair loss army”. The occurrence of androgenic alopecia is related to genetics and androgens, psychological factors can trigger and aggravate the disease, and lifestyle such as staying up late, hair dyeing and perming can also seriously damage hair health. Hair loss can be controlled or even recovered by timely and scientific comprehensive treatment for patients with hair loss. Androgenic alopecia can occur in both men and women, but the performance varies. 2. Alopecia areata is a kind of sudden and limited hair loss, commonly known as “ghost shaving”. The disease can occur at any age, but is more common in young adults. The incidence is the same in both men and women. In most patients, hair loss areas of round or oval shape with different diameters and clear borders appear suddenly on the scalp, and in severe cases, the number increases and fuses with each other to form irregular patches, or even total baldness (total loss of hair) or alopecia areata (total loss of hair along with eyebrows, eyelashes, axillary hair and pubic hair). The prognosis is generally good in mild cases, but poor in severe cases. Most cases have recurrence, and those with the first occurrence in children are more likely to have recurrence.