After autumn, many people find that their hair has dropped even more severely. What's going on? Do you also choose the season for hair loss? What is the true meaning of hair loss, and how much hair is still within the normal range every day? Today, dermatologists teach everyone how to "experience anxiety on the head". Autumn hair loss makes some sense. From the number of hair loss patients who visit daily dermatology clinics, there is no specific seasonal pattern for hair loss. However, there was a study on scalp hair follicles in healthy individuals, which showed that the proportion of hair in the resting period reached a small peak throughout the year in July. This part of the hair that is in the resting period will fall off at the end of the resting period (2-3 months later), and based on time, it happens to be autumn. So, some people's hair loss worsens in autumn, which may be a normal physiological phenomenon. Losing 100 hair pieces per day is not considered hair loss. Hair loss refers to the process and symptoms of hair loss. The scalp hair follicles have a normal cycle, including the growth period (2-8 years), regression period (2-8 weeks), rest period (2-3 months), and hair loss period. So, a certain degree of hair loss is a normal physiological process. The hair loss that we pay attention to in daily life usually refers to abnormal hair loss. There are different types of abnormal hair loss, such as alopecia areata, androgenic hair loss, or hair loss during rest period. Is it too much to lose 100 hair every day? According to the clinical grading scale for hair loss, the number of hair loss is divided into 6 levels. Level 1 is 10 hairs/day, Level 2 is 50 hairs/day, Level 3 is 100 hairs/day, Level 4 is 200 hairs/day, Level 5 is 400 hairs/day, and Level 6 is 750 hairs/day. Grade 1-3 hair loss is normal. If it reaches grade 4 or above, or even reaches grades 5 or 6, it is considered excessive hair loss. So, the average daily hair loss of less than 100 is normal, so there is no need to worry too much. If the daily average hair loss exceeds 200, it is important to note that there may be excessive hair loss. This is the main reason for alopecia. Different types of alopecia have different causes. Among them, androgenic alopecia has the highest incidence rate. Androgenic alopecia is characterized by a slow progressive pattern of alopecia, with males exhibiting alopecia in the frontotemporal and top of the head; Women have significantly sparse hair near the midline of the head. The causes of androgenic alopecia are multifaceted, and current research shows that genetic factors and androgens play a decisive role in the pathogenesis. Factors such as inflammation around hair follicles, increased life pressure, tension, anxiety, unhealthy lifestyle, and dietary habits can all exacerbate the symptoms of androgenic alopecia. The main characteristic of hair loss during the rest period is an increase in acute or chronic hair loss. There are many factors that are affected, including physiological factors, fever, stress, medication, endocrine, organ dysfunction, hair cycle disorders, nutrition, and local factors. COVID-19 infection is also an important inducement of telogen alopecia, which may be caused by hypoxia, inflammation, metabolic abnormalities and drugs. Hair loss after COVID-19 usually occurs 1-2 months after infection. Hair loss usually lasts 2-3 months. It is usually self limiting. After the inducement is eliminated, the hair will resume growth. If the amount of hair loss is large, it will take about half a year to one year