The different types of dark spots
The term ‘pigment spot’ generally refers to any abnormality in skin pigmentation. It therefore does not refer solely to brown spots: depending on the colour observed, several types of spots can be distinguished.
Brown spots, or hyperpigmentation, refer to darker pigmentation in certain areas of the skin. They may be linked, in particular, to increased melanin production or the accumulation of certain oxidation pigments 6(1)
Red patches, or inflammatory patches, may appear following skin inflammation, as in the case of certain marks left by acne or rosacea
White patches, or hypopigmentation, are a result of a reduction in skin pigmentation.
Pigment spots can also be categorised according to their stage of development:
Visible spots are already present on the skin’s surface and can be seen with the naked eye. Their intensity and size may change over time
Invisible spots are still imperceptible to the naked eye, but are already beginning to form beneath the skin’s surface. These clusters of melanin act as a ‘reservoir’ for future pigmented spots
Deep spots are embedded in the deeper layers of the epidermis, or even at the dermo-epidermal junction. They are often older, and may be more diffuse, widespread or persistent.
The aim of a treatment for dark spots is to act on them, whether they are already visible or still forming, whilst targeting the mechanisms that may contribute to their formation.The mechanisms underlying the development of dark spots
When it comes to brown spots, two main mechanisms can be distinguished: those linked to melanin and those linked to lipofuscin.
Melanin is a pigment naturally produced by the skin to protect it. It is produced by melanocytes and then transferred to the cells of the epidermis. Its production is regulated in particular by an enzyme called tyrosinase. When this enzyme is more actively stimulated, melanin production increases and can lead to a build-up of pigment, resulting in brown spots. (1)
This overproduction of melanin can be triggered by various factors, including UV radiation, inflammation, skin ageing or hormonal changes. It is this mechanism in particular that is involved in sunspots, post-inflammatory marks and melasma . (2)
Lipofuscin, meanwhile, is a yellow-brown pigment resulting from the accumulation of damaged and oxidised cellular residues. With age and under the influence of environmental stress, the recycling of these cellular waste products slows down: they can then gradually accumulate within the cells and form lipofuscin deposits.
However, lipofuscin itself has pro-oxidant properties. Its accumulation can promote the production of free radicals, which in turn help to stimulate melanogenesis. Lipofuscin and melanin can thus accumulate and form pigment clusters, contributing to the gradual onset of pigmentary ageing.
An anti-dark-spot approach can therefore aim to target these two complementary mechanisms, by limiting both the overproduction of melanin and the accumulation of oxidation-related pigments.
What factors contribute to the development of dark spots?
Several factors can contribute to the appearance of dark spots or make them more pronounced, particularly by affecting pigment production, inflammation or skin ageing.
Sun exposure is a major factor in the development of dark spots. UV rays stimulate melanin production (1) and can therefore contribute to the development or darkening of brown spots, such as solar lentigines.
Hormonal fluctuations can also influence skin pigmentation. They are notably involved in melasma, which manifests as brown patches often found on the face.
Inflammation is another factor to take into account. Skin inflammation, for example following a blemish, can lead to persistent pigmentation and leave a post-inflammatory mark.
Finally, oxidative stress and cellular ageing can encourage the accumulation of lipofuscin, an oxidation pigment. This phenomenon contributes to the appearance of certain brown spots and explains, in particular, why pigmentation irregularities become more common with age.
Thus, dark spots can be triggered by external factors, such as UV rays, but also by internal factors, such as hormonal fluctuations, inflammation, oxidative stress and cellular ageing. An effective approach to tackling dark spots therefore involves addressing several of these mechanisms simultaneously.
How can you distinguish between pigmentation spots, post-inflammatory marks and scars?
After a blemish, a mark may remain visible for several weeks, or even longer. However, depending on its appearance, it may be a pigmentation irregularity, a post-inflammatory mark or a genuine scar.
A post-inflammatory mark appears following inflammation of the skin, for example after a blemish. It manifests as a change in skin colour, with an area that is darker or redder than the surrounding tissue. However, the texture and surface of the skin remain unchanged.
A scar, by contrast, involves a change in the skin’s structure. It may result in a depression, a raised area or a change in skin texture. It is therefore not caused by the same mechanisms as a simple change in pigmentation.
This distinction is important for understanding what a dark spot treatment can actually achieve: it targets pigmentation irregularities and may therefore be beneficial for post-inflammatory hyperpigmentation. However, it cannot correct a scar that alters the structure of the skin.








