Hyperpigmentation is a common skin disorder caused by an overstimulation of melanin in the skin that results in dark spots or patches on the face or body. It can affect people of any race or skin colour.
What causes hyperpigmentation?
Hyperpigmentation is characterized by a localized overproduction of two pigments: melanin (the pigment responsible for skin colour and produced by melanocytes) and lipofuscin (a pale yellow-brown pigment composed of oxidized proteins and lipids that have lost their function). Although lipofuscin generally does not appear until later in life, its formation can start very early, even before the age of 12.
Many factors can contribute to hyperpigmentation:
Sun exposure causes the stimulation of cells called melanocytes, responsible for the production of melanin. To protect other cells from UV radiation, melanocytes increase their melanin production.
Skin trauma arising from certain skin disorders or controlled skin trauma treatments, such as laser resurfacing or other cosmetic procedures, that result in skin inflammation, may increase melanin production.
Estrogens are capable of stimulating melanin production, which is why hyperpigmentation can also occur as a side effect of hormone treatments, pregnancy, and hormone-altering drugs such as oral contraceptives.
Certain autoimmune and gastrointestinal diseases, as well as metabolic disorders and vitamin deficiencies.
The main drugs implicated in causing skin pigmentation are nonsteroidal anti-inflammatory drugs, antimalarials, amiodarone, cytotoxic drugs, tetracyclines, heavy metals and psychotropic drugs.
- Other skin injuries, including those related to acne: when picking at a pimple, the pimple heals and disappears and leaves a reddish-brown spot on the skin.
Types of hyperpigmentation
There are four main types of hyperpigmentation:
Lentigines include sunspots, freckles, age spots and liver spots. When melanocytes overact and trigger too much melanin, it results in sunspots, typically in the form of freckles or larger age spots. Age spots appear on the body because of a reaction to UV radiation. Commonly known as sun or liver spots, they are brown to black macules that commonly appear on sun-exposed skin after the age of 40 and are due to uneven or excessive production of melanin. They are a significant visual clue to a person’s age and their presence can add up to 10 years to a persons perceived age.
One of the most common types of hyperpigmentation, it is caused by injury or trauma on the skin, such as a cut, burn, scrape, or acne.
Melasma or Chloasma
Mostly affecting women, melasma is triggered by hormonal changes, pregnancy or certain medications. It commonly appears as patchy areas of darker skin on the forehead, cheeks and upper lip that typically appear darker right after sun exposure.
Hyperpigmentation due to illness
Such as Addison’s disease, an endocrine disorder that causes an overproduction of melanin resulting in dark spots or darker skin tones.