“Look at your dirty neck, do not wash it properly!” “I wash it, I wash it every day, I rub it every day, it’s still so black, I don’t know what’s going on!” This is not a few cases, many people with obese body type are troubled by their own neck, armpits and other places where the skin is dark, can not be washed clean problem. This is the time to be aware that this may be a precursor to diabetes. This black neck disease is medically called pseudo acanthosis nigricans, also known as obese acanthosis nigricans, mainly because obese people often sweat in the skin folds, long-term wet, coupled with repeated friction, resulting in skin thickening, black, skin thickening to a certain extent formed a layer of black velvet skin damage, medically known as velvet-like changes. In the long run, a more prominent sarcoma will grow on this layer of black velvet, forming a skin flab. They often occur in the neck, armpits, thighs, under the breasts, and other areas where the skin folds. Studies have shown that this pseudoacanthosis nigricans is a manifestation of the presence of insulin resistance in the body and overproduction of insulin. There are receptors for insulin and insulin-like growth factors on human fibroblasts and skin keratinocytes. This high insulin binds to the receptors and stimulates excessive proliferation of keratinocytes in a manifestation of acanthosis nigricans. Insulin resistance and hyperinsulinemia in the body are the pathophysiological processes of prediabetes mellitus type 2. Without early and timely intervention, it will one day develop into diabetes. In recent years, with the increase in the number of obese children in China, the trend of childhood pseudoacanthosis nigricans has increased significantly. Parents always complain that children are not hygienic, in fact, children, especially small fat pier, neck black may really not be lazy children, but pseudo acanthosis nigricans in the blame. The younger the age at which obesity occurs and the longer the history of the disease, the greater the risk of leading to diabetes. We always mistakenly believe that diabetes is a disease that only affects older people, but this is not the case. Today, the onset of type 2 diabetes is significantly younger, and type 2 diabetes in children is no longer a minority. Therefore, a dark neck may no longer be a sign of whether a person is hygienic or not, but a signal from the body to alert us that there is likely insulin resistance in your body. If your family or friends are troubled by this black neck disease, make sure to go to the hospital for timely examination. Early intervention, active participation in physical exercise, diet control, weight loss, and prevention of the occurrence and development of diabetes.