How can skin peeling be prevented after sunburn?

Exposure to UV rays, particularly UVB, triggers a cascade of reactions in the skin. Within the first few hours, the exposed keratinocytes release cytokines, as well as vasoactive and neuroactive mediators, which induce an inflammatory response characteristic of sunburn, causing redness and a painful sensation. When the UV dose exceeds a certain threshold, the keratinocytes activate their apoptotic pathways and die. These cells, called "sunburn cells", are identifiable by their condensed nucleus. Their removal is a protective process : it prevents the survival of damaged cells that could, in the long term, lead to DNA mutations. This mechanism explains the peeling visible a few days after exposure.

In parallel, UV radiation activates the tumour suppressor gene p53, which stimulates DNA repair mechanisms, a phenomenon rapidly followed by keratinocyte proliferation. This intense cell division leads to epidermal hyperplasia, which thickens the stratum corneum and forms an additional barrier against future UV exposure.

The accelerated shedding of the skin following sunburn or a prolonged session of tanning corresponds to the removal of apoptotic keratinocytes and their replacement by new epidermal cells to protect the skin.

The best strategy to prevent the skin from peeling after a sunburn prevention remains key. Once keratinocytes are damaged and committed to apoptosis, it is difficult to prevent desquamation. That is why limiting the initial UV exposure is so important.

Prevention is based on two pillars: protecting the skin by applying a sunscreen and moisturising it after exposure.

Indeed, the first instinct is to apply a broad-spectrum sunscreen, covering both UVA and UVB rays. The sunscreen filters act as a shield that absorbs UV rays and converts them into heat, thereby limiting their penetration into the skin and the activation of inflammatory pathways. Furthermore, it is important to apply the cream, stick or sunscreen lotion in sufficient quantity to achieve the protection stated on the packaging. The correct amount? The equivalent of a teaspoon for the face and neck, and a tablespoon for each arm or leg. Another essential point: reapply the sunscreen every two hours, particularly after swimming or when perspiring.

Beyond sunscreen, preventing the peeling phenomenon also involves sun exposure management. Between 12:00 and 16:00, UV radiation reaches its peak intensity, vastly increasing the risk of sunburn and therefore peeling. Favour shade, wear long, lightweight clothing and a wide-brimmed hat – simple yet effective measures. This clothing-based photoprotection works in synergy with sunscreens to reduce the UV dose reaching keratinocytes.

After sun exposure, it is also important to implement certain measures to repair the skin and prevent it from peeling. We recommend, first of all, that you apply twice daily an after-sun treatment. This type of product, often enriched with humectant agents such as glycerine or hyaluronic acid, promotes water retention in the epidermis and alleviates sensations of tightness. After-sun products also contain soothing actives, such as aloe vera, bisabolol or panthenol, which help to calm inflammation and support cellular repair, thereby limiting the severity of peeling.

• SCOTT T. & al. UV radiation and the skin. International Journal of Molecular Sciences (2013).

• ZHANG S. & al. Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin. Environment International (2024).