White patches on the back of the neck may be related to unpigmented nevi, vitiligo, lichen planus and so on. 1. Apochromatic nevus: If it appears on children or infants, it is usually congenital pigment loss. Resulting in anaplastic nevus, the edge of the nevus is blurred and most of them may be jagged, which can grow in the same proportion with the affected children and usually does not affect the health. 2. Vitiligo: closely related to mental stress and autoimmune dysfunction. It is mainly due to the damage and destruction of local skin melanocytes, resulting in a lack of melanin. The color of white spots is usually porcelain white. 3. lichen planus: after Malassezia infection of local skin, it will produce the function of inhibiting melanin production, resulting in local white spots. White patches on the back of the neck can also be seen in other causes, it is recommended to seek medical attention in a timely manner, follow the doctor’s instructions for relevant examinations, with the help of the doctor to clarify the cause, and targeted treatment or treatment.