There is a black patch of skin on my back, what's going on?

Some people find that some of the skin on their backs is dark. In this case, they should pay attention to whether it is caused by a lack of scientific diet. If they prefer to eat foods rich in zinc, iron and copper, it is easy to cause dark skin. The use of drugs and black precipitation may also cause this symptom. So after understanding the cause, we will know how to prevent it.

1. The foods you like are rich in zinc, copper and iron. Certain foods are also the cause of darkening of the skin. Foods rich in metal elements such as copper, iron, and zinc have this disadvantage. These metal elements can directly or indirectly increase the amount and activity of substances such as tyrosine and tyrosinase that are related to melanin production. These foods mainly include animal liver, kidney, oysters, shrimp, crab, beans, walnuts, black sesame and raisins.

2. The drug has affinity to melanin. Many drugs also change the normal skin color. For example, chloroquine has a strong affinity for melanin, which aggravates skin discoloration; about 10% of patients taking quinine develop blue pigment spots on their faces. Sedatives pose the greatest threat to skin color. Those who take them for a long time will develop butterfly spots on their face and neck, and their arms and other parts will turn brown-gray, light blue or light purple. In addition, repeated use of mercury-containing ointments can also leave brown pigmentation on the affected area. There are more anti-cancer drugs that cause skin color changes.

3. Certain diseases are triggers. Many diseases can change the normal skin color and make it darker. Among them, the more common ones are endocrine system diseases, chronic wasting diseases, malnutrition diseases, etc. These diseases can cause the skin to turn brown or dark brown, which is particularly obvious in exposed areas such as the face, back of the hands, joints, or areas that are subjected to pressure and friction. For example, chronic liver disease can cause chloasma on the face or darkening of the area around the eyes.

4. The natural environment damages the skin. The culprit is ultraviolet rays, which stimulate the melanin in the skin and induce skin lesions such as freckles. Even on cloudy days, the "ultraviolet rays" are still strong. Ultraviolet rays can cause skin darkening, aging, and wrinkles. Human skin's response to ultraviolet rays causes redness, tanning and increased thickness of the epidermis in acute reactions, and causes skin aging in chronic reactions.