Hyperpigmentation refers to excessive melanin production by melanocytes, resulting in areas of skin that are darker than the surrounding skin tone. This process is triggered by the activation of tyrosinase—the key enzyme in melanogenesis—in response to various stimuli, such as UV radiation, skin inflammation, hormonal fluctuations, or repeated friction. Hyperpigmentation is not a single condition but a mechanism common to several skin manifestations, the intensity and location of which vary depending on the triggering cause and phototype.
The term “hyperpigmentation” encompasses several distinct conditions that share the same underlying mechanism but have different causes. Melasma is a hormonal form of facial hyperpigmentation, often triggered by pregnancy, birth control, or sun exposure, and typically presents with symmetrical borders. Age spots (actinic lentigines) result from cumulative sun exposure over several decades, primarily on sun-exposed areas (hands, face, décolletage). Post-inflammatory hyperpigmentation, on the other hand, appears after local skin trauma, regardless of age or hormonal status.
Post-inflammatory hyperpigmentation (PIH) occurs after a skin lesion: an acne pimple, cut, burn, eczema, or friction. Inflammation locally stimulates melanocytes, which produce excess melanin at the site of the healed lesion, leaving a brown or grayish mark that lasts for several weeks to several months. This phenomenon particularly affects medium and dark skin types, in whom the melanocyte response to inflammation is naturally more pronounced. The mark usually fades on its own, but its fading can be accelerated with targeted skincare.
Several cosmetic active ingredients act on melanogenesis to help even out the complexion. Vitamin C inhibits tyrosinase and provides additional antioxidant protection; it combines effectively with vitamin E to enhance protection against oxidative stress. Licorice, rich in glabridin, is a natural tyrosinase inhibitor recognized in skin-brightening cosmetics. Niacinamide limits the transfer of melanin to surface keratinocytes, helping to visually reduce dark spots over several weeks of regular use.
Sun protection is the most critical measure for preventing the worsening or recurrence of hyperpigmentation: even moderate sun exposure reactivates melanin production in areas already affected by hyperpigmentation. Daily use of SPF 50 sunscreen is essential when treating hyperpigmentation, even on cloudy days. Avoiding scratching or picking at inflammatory lesions (acne, insect bites) reduces the risk of post-inflammatory hyperpigmentation. Regular gentle exfoliation promotes cell turnover and the gradual fading of pigmented areas, provided that sun protection is consistently reinforced in the days that follow.
A dermatology consultation is recommended if a spot changes in shape, color, or size; bleeds or itches; or in cases of widespread hyperpigmentation that does not respond to standard skincare products. A dermatologist may recommend more targeted solutions (prescription depigmenting treatments, medical peels, or laser therapy) when cosmetic treatments are insufficient to reduce the discoloration.
