Neck black wash may be sun exposure, inflammation, acanthosis nigricans and other causes.
1. Sun exposure: If the neck is in a sunny environment for a long time, ultraviolet radiation can stimulate the melanocyte function to enhance, which leads to increased melanin synthesis, resulting in the phenomenon of the neck black and black can not be washed off.
2. Inflammation: neck skin due to the occurrence of infection, allergy patients, after the cure, usually appear after the inflammation of hyperpigmentation. Mainly because the inflammation products can produce stimulation of melanocytes, which leads to an abnormal increase in melanin synthesis, resulting in epidermal hyperpigmentation, which leads to the phenomenon of the neck black black can not be washed off.
3. Acanthosis nigricans: this disease can lead to localized skin melanosis, can appear neck black symptoms, can also appear in the groin, armpits and other skin folds more parts.
It is recommended that patients with black neck that cannot be washed off should go to the hospital in time, under the guidance of the doctor to clarify the cause of the disease and take effective treatment.