Baldness may be caused by androgenetic alopecia, patchy baldness, malnutrition, hypothyroidism, etc. It needs to be analyzed according to the symptoms. 1. Androgenetic alopecia: Most common in males, often develops in puberty, manifested as progressive reduction, thinning and alopecia or thinning of hair on the head, this disease has a genetic predisposition, androgen is one of the important mechanisms for the development of this disease. 2. Patch baldness: Patch baldness is a psychogenic, autoimmune-associated, non-scarring hair loss disease that can occur on any part of the body. It is currently believed that it may be related to genetics, mental and emotional stress, endocrine disorders, immunoinflammation and other factors, and may belong to the category of polygenic diseases. 3. Malnutrition: If the patient’s long-term diet is not balanced or gastrointestinal dysfunction leads to malnutrition, it will affect the hair follicles, so that the supply of nutrients to the hair is insufficient, which will lead to alopecia areata and baldness. 4. Hypothyroidism: Hypothyroidism can lead to thinning and drying of hair, which can also cause baldness. When baldness occurs, it is recommended to go to the hospital in time for a detailed examination and standardized treatment under the guidance of the doctor.