Androgenetic alopecia, also called androgenetic alopecia, seborrheic alopecia and premature baldness, has about 160 million patients in China, of which 130 million are men. Although it has no effect on physical health, hair loss can cause considerable psychological stress to patients: when looking for a job, especially when looking for a date, thinning hair can easily cause serious lack of confidence, and many young patients come to the clinic accompanied by their parents or girlfriends. When you scratch your head, you lose a few, there is always hair on the floor sofa, and you are even more frightened when you wash your hair …… Are you moving closer to the hair loss camp? In fact, hair growth is a cyclical, periodic process, each hair growth after a certain time will enter a degenerative phase, hair roots gradually shrink, enter the resting phase, and finally fall off, and enter a new growth cycle, grow new hair. A normal person has about 100,000 hairs, of which about 10% are in the resting phase. It is normal to lose 50-100 hairs per day, which is physiological hair loss. However, if hair loss exceeds 100 hairs per day for 2-3 months in a row, you need to suspect the existence of pathological hair loss and should visit a regular hospital for consultation and examination. There are many kinds of hair loss diseases and their causes are very complicated. Among the many hair loss diseases, androgenetic alopecia accounts for the vast majority, more than 90%. In the scalp of patients with androgenetic alopecia, the hormone content of dihydrotestosterone increases, leading to accelerated degeneration of hair follicles, making them thinner, softer and shorter, and even forming empty hair follicles. On the other hand, the hair in the anagen phase is getting less and less, and the hair in the resting phase is getting more and more. Therefore, the hairs of patients with androgenetic alopecia will become thinner while becoming less and less. A doctor specialized in hair loss can help determine the presence of abnormal hair loss and the type of hair loss through a variety of tests. Here are a few relatively simple methods that do not require special instruments and that you can do for yourself at home. The most visual method is to observe the ratio of hair thickness to its root pattern. One of the simplest is the hair pulling experiment: use your thumb and forefinger to pinch a small handful of hair (about 50 or 60) from close to your scalp and stroke it upwards, the hair that is stroked off is the resting hair, if you don’t wash your hair for 5 days and more than 6 hairs are stroked off at a time, it means that there is hair loss and it is increasing. If you don’t wash your hair for 1 day and can stroke off more than 2-3 hairs at a time, you need to be careful about hair loss. In addition, there is another simple check that can greatly improve the ability to judge the state of hair with the naked eye. Because the hair is black, we can put the white hair inspection card on the back of the hair as a background to observe the ratio of the thickness of the hair, but also to better observe the state of the hair root, if it is yellow hair or white hair, you can use the black card, at home you can use white or black paper to replace the inspection card. (Figure 1) Figure 1 hair inspection card In recent years, the latest domestic introduction of a test means, dermatoscopy. The dermoscope is not a normal magnifying glass, it can observe not only the hair and pores on the surface of the scalp but also the scalp deep into the dermis through polarized light technology. Through dermatoscopy, uneven hair thickness and hair shaft diameter differences of more than 20%, as well as an increase in fine hair, a decrease in the number of hairs in the follicular unit, or even empty hair follicles can be found, in line with these characteristics to be considered for the diagnosis of androgenic alopecia, and the examination is very simple and painless. This method is very useful for diagnosing early androgenetic alopecia, especially if the onset is early or if there is no family history. The physician will also perform a staging based on the location and pattern of hair loss, which will clarify the severity of androgenetic alopecia on the one hand, and more importantly, allow the physician to develop an individualized treatment strategy for the patient with hair loss depending on the staging. The traditional Norwood-Hamilton typing and Ludwig typing have many limitations and the results evaluated by each physician sometimes vary widely. In recent years, East Asia has begun to use the Basic and Specialized Type (BASP) classification, which is a combination of staging based on the shape and location of the hairline as well as the location and severity of hair loss on the crown of the head. The specific types include L, M, C and U. The letters represent the shape of the hairline, so U type has a larger area of hair loss than C type; V and F types represent the area of hair loss on the top of the head. This method is now also gradually recognized worldwide Hair loss typing requires standardized photography, which can be used not only for judgment of the condition, providing a basis for the formulation of treatment plans and prognosis assessment, but also as an indicator for efficacy observation in the process of treatment. If available, it is recommended to take six photographs of the patient’s head: one from the front, one from 45 degrees above the front, and one from 90 degrees directly above the front, then put on a hairpin to expose the hairline and take another set of photographs from the front and two from the left and right sides, and in the case of patients with U-shaped hair loss (i.e. hair loss to the back of the head), another one from the front and back. Dr. Cheng Zhou suggests that if you need to get better analysis, judgment, advice and guidance from your doctor through online consultation, as well as long-term follow-up and treatment effect observation, it is better to take photos of hair loss and upload them. In addition, depending on the patient’s specific situation, a series of tests and examinations may be required to exclude other factors affecting hair loss. For example, thyroid function or sex hormone level check, if the gonadal development itself has abnormalities, using only hair loss drugs will not be very effective, and need to treat the original disease; female patients with symptoms such as more hair on the face, acne, menstrual irregularities, etc., need to check for polycystic ovary syndrome. Dr. Zhou reminded us that hair loss treatment as early as possible to stop the complete degeneration of hair follicles, the later the treatment, the worse the effect; at the same time, hair loss treatment is still a protracted war, must follow medical advice to adhere to long-term medication. The use of wig sets, hair pieces or pomades can improve the appearance, but be sure to choose products from regular manufacturers. Patients with a lot of oil are not recommended to use shampoos that are too strong in removing oil to prevent compensatory oil secretion from making the oil more serious. Finally, in addition to medication, we also hope that patients with hair loss will take care of their hair in daily life, avoid excessive stress and fatigue, reduce stress, smoke less, and reduce perming, hair dyeing and other behaviors that can damage hair quality. 1. Chinese Society of Dermatology and Venereology, Hair Group. Guidelines for the treatment of androgenic alopecia in China. Journal of Clinical Dermatology 2014(43):182-186 2. Lee WS et al. A new classification of pattern hair loss that is universal for men and women: basic and specific (BASP) classification. j. Am. Acad. Dermatol., 2007 Jul;57(1):37-46.