The left side of the head long white hair may be a normal physiological phenomenon, may also be caused by genetic factors, vitiligo and other diseases. 1. physiological phenomenon: the left top of the head white hair may be a normal physiological phenomenon, with age, resulting in hair pigmentation degenerative decoloration caused by physiological white hair, usually do not need special treatment. 2. genetic factors: the head of the left side of the long white hair may be genetic factors, if the family has a teenage white hair, will increase the chances of disease, if the patient daily nutritional deficiencies or hair pigment particles are relatively small may also cause the head of the left side of the long white hair situation. 3. Vitiligo: If the patient himself suffers from vitiligo and other diseases, the lesions involved in the head of the head of the left side of the head of the skin, damage to the hair follicles in the melanocytes, resulting in its normal synthesis of melanin, can also cause the head of the left side of the head of the symptoms of the hair, the patient may also appear in localized skin pigmentation of the case of hypopigmentation. It is recommended that the patient timely medical examination, clear cause for targeted treatment, so as not to delay the condition.