disease
Many diseases will change the normal skin color and make it black. Among them, the most common diseases are endocrine system diseases, chronic wasting diseases and malnutrition diseases.
For example, Addison's disease caused by hypoadrenocortical function can make the skin brown or even dark brown, which is distributed in exposed parts such as face, back of hand and joints, especially wrinkles or compression and friction. Another example is chronic liver disease, which can cause chloasma on the face or blackening around the orbit. In addition, melanosis patients' melanin mostly accumulates on the face, especially on the forehead, cheeks, behind the ears, neck and other parts, which is unsightly.
In addition, acromegaly, hyperthyroidism, hemochromatosis, chronic infectious diseases such as tuberculosis, malaria and leishmaniasis, dermatomyositis, renal failure, cancer and other diseases can also cause melanosis of the skin.
There is also a kind of skin diseases, especially those caused by some allergic foods, such as raw onions, garlic, peppers, peppers, leeks, wine, fish and shrimp, kelp, chickens and ducks, pig's trotters, pig's heads and other foods, commonly known as "hair", which can also induce skin allergic reactions, produce rashes, and finally leave pigments, making the skin black.
medical science
Many drugs can change the normal skin color, among which drugs for malaria are the most harmful. After three or four months of general medication, 25% of the users can deepen the skin pigment. For example, adipine can make skin color orange; Chloroquine has strong affinity for melanin, which can aggravate the blackening of skin color; About 10% of patients taking quinine have blue pigment spots on their faces.
Among sedatives, chlorpromazine is the most threatening to skin color. If you take it for a long time (such as mental patients), butterfly spots will appear on your face and neck, and your arms will turn brown-gray, light blue or light purple.
The skin blackening caused by metal drugs can not be ignored, for example, arsenic combines with sulfhydryl groups in tyrosinase of epidermal melanocytes, which makes copper in a free state, activates tyrosinase, increases the synthesis of melanin and darkens the skin color. In addition, repeated use of mercury-containing ointment is easy to leave brown pigment on the lesion.
Among anticancer drugs, there are many drugs that cause skin color change. For example, myelin can turn skin color into reddish brown, and bleomycin can produce melanin deposition.
Others, such as anti-leprosy drugs, are worried about turning the skin dark gray, while the anti-epileptic drug phenytoin sodium is worried about inducing chloasma, which is particularly harmful to women.
food
Some foods are also the bane of skin blackening, and foods rich in copper, iron, zinc and other metal elements have this shortcoming. This is because these metal elements can directly or indirectly increase the quantity and activity of tyrosine, tyrosinase and dopaquinone related to melanin production. Remember, these foods include animal livers, animal kidneys, oysters, shrimps, crabs, beans, walnuts, black sesame seeds, raisins and so on. Women who love beauty should eat carefully.
sunlight
Ultraviolet rays in the sun will stimulate melanin in the skin, induce skin lesions such as freckles, and affect beauty. Therefore, beauty experts say that sunlight is the enemy of skin, emphasizing that women should be especially careful.
Wipe yourself with a wet towel.
Many people like to rub their skin hard when taking a shower, in order to clean it up. As we all know, excessive force or repeated rubbing can easily lead to skin blackening, which is called "friction melanosis".
The pathological cause of friction melanosis has not been completely revealed, but it has been confirmed by experts that it is directly related to rubbing. This is due to the local skin being subjected to strong friction, oppression and other mechanical stimulation, which is more common in people who have strong friction with bath towels or chemical fiber bath towels. It is characterized by light brown to dark brown pigmentation, diffuse reticulation, and is prone to occur in the protruding parts of bones such as clavicle, ribs, scapula, elbow and knee.
Prevention and control countermeasures
Generally speaking, after removing the causes of discoloration, such as disease recovery, drug withdrawal, fasting hair, using sunscreen, and taking a bath without overexertion. , skin color will have a certain degree of recovery.
You can also eat more foods rich in vitamin C, such as tomatoes, fresh dates, hawthorn, spinach, citrus, kiwi fruit, green vegetables and so on. Vitamin C can interrupt the process of melanin production, prevent the generated dopaquinone from further oxidation and reduction to dopa, reduce the synthesis of serum copper and serum copper oxidase, and keep the skin fair.
You can also help with wine and vinegar. The method is: add peeled apples into rice wine, soak for several days, then add buckwheat, after one week, filter out the medicinal liquor and rub the skin. Or mix vinegar and glycerin at a ratio of 5: 1 and apply it to the face, or make the thick skin delicate and white.