Uneven skin tone, or hyperpigmentation, is a common skin condition that causes patches of skin to become darker than the surrounding areas of skin. Hyperpigmentation appears around the mouth, and on the face most commonly. What’s more, there are several distinct types of the condition.
Hyperpigmentation is also more prominent in Black skin and darker skin tones.¹
Types of Skin Pigmentation
Firstly, age spots, sometimes called liver spots, are a common type of hyperpigmentation. They are small, darkened patches of skin, that appear as age spots on the face, as well as the hands and other areas commonly exposed to the sun.
Another type is melasma. These are similar to age spots but are usually larger and appear most commonly during hormonal changes.
The third most common type is post-inflammatory hyperpigmentation (PIH). This occurs when the skin produces excess melanin after it has been injured or irritated.
Hyperpigmentation Causes
There are several different causes. Firstly, sunlight is the number one cause of hyperpigmentation.
This is because sunlight triggers the production of melanin, which is the skin’s natural pigment. Melanin acts as the skin’s natural sun protector which is why your skin goes darker and tans in the sun. However, too much sun exposure can cause the body to produce too much melanin, leading to uneven skin tone and darker patches.
Additionally, hormonal changes are another big cause. This form of skin pigmentation occurs most commonly in women because of the female sex hormones, estrogen and progesterone, stimulating the overproduction of melanin. This then leads to the formation of dark spots. This type of pigmentation is most common in periods when estrogen levels are high, such as during pregnancy, or when taking birth control.
Thirdly, conditions such as acne can also cause skin discolouration. Hyperpigmentation from acne appears as dark patches on the skin, after acne blemishes have faded. Pigmentation can occur following inflammation, as inflammation can stimulate the production of melanin.
References
1. C. Davis E D, Callender V. Postinflammatory Hyperpigmentation A Review of the Epidemiology, Clinical Features, and Treatment Options in Skin of Color. The Journal of Clinical and Aesthetic Dermatology. 2010 Jul; 3(7): 20–31.
2. Vashi N, Kundu R. Facial Hyperpigmentation: Causes and Treatment. British Journal of Dermatology. 2013;169:41-56.