If you are experiencing patches of discoloured skin, you may be wondering: what is skin pigmentation, and what causes it? Let’s find out.
What is Skin Pigmentation?
Skin pigmentation refers to the colour of the skin, and is determined by the presence and distribution of melanin. There are primarily two types of melanin: eumelanin, which is responsible for brown and black pigments, and pheomelanin, which contributes to red and yellow pigments. The amount and type of melanin in the skin varies among individuals, leading to differences in skin colour. Excess production of melanin in certain areas of the skin can result in hyperpigmentation, a common condition characterised by patches of darker or discoloured skin.
What Causes Hyperpigmentation?
Now we have answered the question “what is skin pigmentation”, let’s find out what causes it. There are various causes of hyperpigmentation, each of which are important to know when deciding on the best treatment. Let’s take a look.
Damage caused by excessive sun exposure is one of the main causes of hyperpigmentation. If you spend too long in the sun, your skin will try to protect itself from the detrimental UVA rays by producing more melanin. The extra melanin production is the reason for the glowy tan you can achieve out in the sun. However, when the sun doesn’t make melanin evenly, you will notice the hyperpigmentation appear in blotchy patches. The damage caused by sun exposure often appears with age, so the hyperpigmentation is often referred to as sunspots, age spots, or liver spots.
Medical Conditions: Addison’s Disease
Though increased pigmentation in itself is not harmful, it can sometimes be a symptom of a medical condition. Addison’s disease is a rare disorder of the adrenal glands that results in patches of hyperpigmentation. Usually, this hyperpigmentation occurs in areas of the body most exposed to friction and the sun, such as the face, neck, elbows and knees. This condition has a stimulant effect on hormones, resulting in increased melanin synthesis.
Some medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), certain antibiotics and chemotherapy drugs may cause hyperpigmentation as a side effect. An estimated 10-20% of hyperpigmentation cases result from medications. Though hyperpigmentation as a side effect can happen to anyone, it is more common in women.
Hormonal changes within the body can result in hyperpigmentation. This is a common experience during pregnancy, when hormone levels increase significantly. Hyperpigmentation during pregnancy usually occurs on the face, so it is also known as melasma, or the ‘mask of pregnancy’. You can find out more about melasma here.
Over 125 genes are known to affect skin pigmentation, and genes are also responsible for the regulation of melanin production. Some individuals may have a genetic predisposition to developing hyperpigmentation, shown through conditions such as freckles. The number of melanocytes, the melanin producing cells that are within the skin, is also genetically predetermined.
Inflammation & Trauma
Skin inflammation caused by conditions like acne, eczema, or psoriasis can trigger an overproduction of melanin, leading to hyperpigmentation in the affected areas. Skin injuries such as cuts or burns may cause hyperpigmentation during the healing process. This is known as post-inflammatory hyperpigmentation.