Melanin production can be affected by a number of factors. However, it is important to note that skin pigmentation is generally determined by hereditary factors.
Sun Exposure
One of the most important factors that affect skin pigmentation is ultraviolet light exposure which comes from sun exposure. The melanin found in the skin is the natural defense against the harmful effects of the sun. Depending on the amount of time spent in the sun and the amount of exposure, the skin will react by creating more melanin to filter out the UV light.
Brief exposure will cause immediate tanning of the skin where the melanin will become darker, but the amount will remain the same. This will take a few hours or days to resolve. However, in cases of longer and heavier UV exposure, the amount and activity of melanocytes will increase. This can take months to resolve and for the skin to return to normal.
According to Dore Aesthetics, it is possible for sun exposure to cause dark spots on the facial skin. Liver spots or sun spots are the result of long-term exposure and are also linked to aging. People with fair skin are also more prone to freckles which are seen in sun-exposed areas such as the face.
Medical Conditions
There are many medical conditions which will cause the skin to darken. This will include diseases related to the adrenal glands, liver disease, hyperthyroidism, some types of cancer and diabetes. If you see any strange changes to the tone of your skin, you should consult a doctor to see if there is a medical cause.
Hormones
Women who are pregnant or taking oral contraceptives are more prone to melasmacontraceptive pills. These are large, dark brown patches that appear on the face, often located on the forehead, cheeks and over the nose. The spots are caused by the higher levels of estrogen in the body which will increase the melanocyte activity.
Medications
There are some medications that will increase the production of melanin. These medications will include certain anti-seizure drugs, antibiotics, heavy metals, painkillers and chemotherapy drugs. The increased production will generally occur on sun-exposed areas such as the arms and face.
Post Inflammatory Hyperpigmentation
Skin inflammation and injury can cause the skin to speed up the rate of melanin production. This will cause dark spots to appear in the damaged area and when this happens it is called post-inflammatory hyperpigmentation.
This can be caused by eczema and other skin conditions such as acne and chemical damage. These spots are known to take years to clear. If chemical peels and skin lighteners are used incorrectly, they can cause this and do more harm than good to the skin.
These items are known to damage and irritate the skin which leads to it producing more pigmentation. There are many people who have suffered from darker skin tones after they have used these products. Some of the popular skin lightening products on the market are known to cause ochronosis which causes a blue-black discoloration of the skin.
Dry Skin
While dry skin itself will not cause the tone to darken, it will make the skin more prone to itching and irritation. This will lead to skin darkening because of the trauma that is caused to the skin.
Obesity
There are many skin problems caused by obesity including skin darkening. People who suffer from obesity will generally have higher hormone levels which cause acne. Obesity will also lead to acanthosis nigricans which is a thickening and darkening of the skin. This will most common in the skin folds, but can also occur on the face.
Poor Nutrition
Skin health is affected by your diet and there are certain vitamins and minerals which your body needs to fight against harmful free radicals. These nutrients will also play a role in the production of new skin and wound healing. Poor nutrition will quicken skin aging and damage.
