how to reduce or even eliminate the marks left by acne?

Even after the acne blemish is gone, it can leave marks on the skin. Among these marks, you will find:

• Post-inflammatory hyperpigmentation marks, which are a type of hyperpigmentation, manifesting as persistent brown or black spots. Depending on the color of the skin, they are caused by an increased production of melanin in response to an inflammatory reaction. Indeed, the appearance of these hyper-colored areas is based on the production of inflammatory cytokines, with pro-pigmentogenic properties, by the surrounding cells. These cytokines activate the melanocytes (melanin-producing cells), leading to a significant release of melanosomes (pigment granules) and therefore to a surplus of melanin. Although this phenomenon can affect all skin types, it is generally more common among people with mixed to dark skin (phototypes IV to VI).

• Post-inflammatory erythema (PIE) is a small, persistent, pinkish-reddish flat spot that appears as a result of inflammatory acne. When the skin experiences a bacterial infection, the blood flow to the area of the acne increases. As a result, these marks are caused by the dilation of the blood capillaries. These red marks are more visible on lighter skin.

Unlike acne scars, these marks are temporary and usually disappear without leaving scars after several months (between 3 and 24 months). Sometimes it takes several years. However, the speed of their disappearance depends on your exposure to the sun, which can lengthen the healing time. It also depends on the difference between the color of your skin and the color of the mark.

People who suffer from EPI necessarily have a decrease in the lipidic barrier function of the epidermis. However, the most fundamental thing is to keep the skin hydrated, as it needs water to heal better. The care products used, must target both inflammation and the repair, as well as the maintenance of the skin barrier. The following agents should therefore be favored:

• Azelaic acid: In addition to their antioxidant properties, azelaic acid also has anti-inflammatory activity. Studies have shown that azelaic acid inhibits the production of pro-inflammatory cytokines, such as the interleukins IL-1β and IL-6, and the transcription factor TNF-α. Furthermore, another study showed that azelaic acid promotes the regulation of kallikrein-5 (serine protease) in epidermal keratinocytes, which will in turn lower cathelicidins (anti-microbial peptides), decreasing the inflammatory processes.

• Centella asiatica: This herbaceous plant, native to Asia, is used in cosmetics for its healing and repairing properties due to the presence of madecassoside and asiaticoside. It is also appreciated for its moisturizing action due to the presence of sugars that have a strong affinity with water and therefore increase the moisture content of the skin. Finally, Centella asiatica also has an anti-inflammatory activity, thus reducing inflammations.

• Ceramides: Those are lipids naturally present in the skin. They constitute 50% of the skin barrier. The ceramides in care products allow to regenerate the skin's own ceramides and thereby restore the lipidic layer of the epidermis. They help to maintain the skin hydrated and protected against the external attacks, therefore limiting irritations. Indeed, they maintain the cohesion of the various elements of the skin and form a protective layer.

• Niacinamide: This vitamin increases the synthesis of ceramides, free acids and cholesterol, which are contained in the intercellular spaces of the stratum corneum. This encourages a functional cutaneous barrier and therefore a good level of hydration. It also has anti-inflammatory properties.

• Panthenol: Also known as provitamin B5, this cosmetic ingredient has the ability to absorb and retain moisture from the air to increase the water content of the stratum corneum, but also to create a film on the surface of the skin to reduce transepidermal water loss. Clinical studies have also reported its healing potential by stimulating cell growth, which would result in faster healing.

To treat acne marks, there are other options. These range from topical medication solutions to laser treatments and peelings:

• Intense Pulsed Light: This non-invasive, non-ablative treatment uses high-intensity pulses of light. To eliminate brown spots, pulsed light targets melanin on the surface of the skin to remove discoloration.

• Chemical peel: The principle of the peel is slightly similar to that of the scrub. It consists of applying a chemical substance (glycolic acid, salicylic acid, tricholoroacetic acid, etc.) in various concentrations to the skin in order to trigger a controlled desquamation of the epidermis. Melanocytes and marks left by pimples are removed. As a result, blisters form and eventually peel off leaving a smooth skin without hyperpigmentation. This procedure should be performed by a dermatologist, preferably in the fall or winter.

• Low-energy laser pigment therapy: The goal is to destroy hyperpigmented skin cells using high-energy light. The result is new, blemish-free skin. However, this treatment can cause slight damage (burning sensation, irritation...) and HPI

• The KLIGMAN Trio: Dr. KLIGMAN has developed a formula based on the combination of three uniquely synergistic components: hydroquinone (tyrosinase inhibitor), hydrocortisone (anti-inflammatory action) and retinoic acid (accelerates cell renewal). Together, they have demonstrated a depigmenting effect on the various stages of the melanin cycle. The effects of depigmentation appear after 3 to 5 weeks of treatment. However, this solution may cause irritation and sensitivity. Moreover, it does not exclude a recurrence of brown spots.