Androgenetic alopecia and baldness can be differentiated by medical history, clinical manifestations, and hair pulling test. 1. Medical history: Androgenetic alopecia has a genetic predisposition and develops around puberty. Some of the baldness patients have family history, and it is closely related to stress and other neuropsychiatric factors, and can occur at any age. 2. Clinical manifestations: androgenetic alopecia is mainly manifested as progressive reduction, thinning and alopecia of head hair, with characteristic “high forehead” or “horseshoe shape”; patchy baldness is mainly manifested as sudden and coarse line of round or oval hair loss area, with clear boundary and no inflammation. Smooth skin, no inflammation, etc. 3. Hair pulling test: Androgenetic alopecia can appear positive hair pulling test, i.e., within 5 days without washing the hair, pulling up 50~60 hairs with fingers, gently sliding along the hair shaft to the tips of the hair, and pulling down more than 6 hairs. It is recommended that hair loss patients go to the hospital in time, after the cause of the disease is clear, under the guidance of the doctor for standardized treatment.