There are numerous reasons for growing a white beard, which can be categorized as physiological and pathological. Pathologic causes include endocrine diseases and skin diseases. 1. Physiological: Natural growth and aging of the body can cause a decline in melanin secretion, resulting in white beard and gray hair and other symptoms, which is a normal physiological phenomenon and does not require additional special treatment. 2. Pathological: endocrine disease is one of the most common causes of long white beard, such as thyroid dysfunction and other diseases, these diseases make melanin synthesis abnormal, thus appearing this symptom; there may be skin diseases, such as vitiligo and other diseases, vitiligo can make the hair follicle loss of pigment, thus appearing this symptom. If you suspect that the white beard is pathological, you need to go to the hospital for professional diagnosis and treatment.