The sun is shining, the birds are singing, but your skin cells are howling. And especially if you overuse these warm rays. From simple sunburn, to pigment spots to skin cancer, including solar keratosis: multiple damages but only one responsible! Explanations.

Le solar radiation corresponds to the set of electromagnetic waves emitted by the sun. It is made up of ultraviolet rays, cosmic rays, radio waves and visible light. Solar radiation is filtered by the ozone layer before reaching dry land. It is essential for the survival of most plants via the process of photosynthesis.

If sunlight brings many benefits to humans (such as regulating the circadian rhythm and mood but also the synthesis of vitamin D), it can also become deleterious in the event of prolonged or repeated exposure: eye damage, sunburn, premature aging, pigmentation disorders, solar intolerance, immune disorders, solar keratosis, malignant melanoma or skin cancer.

Ultraviolet light penetrates skin cells and generates free radicals that damage them. They are the cause of wrinkles, fine lines, and age spots but also the development of skin cancer.

There are three types of ultraviolet (UVA, B and C). Prolonged exposure to UVA rays causes premature aging of the skin as they penetrate deep into the dermis. They are present at all hours of the day and pass through glass and windows. UVA rays provide a superficial and non-lasting tan.

In order to slow down the process of skin aging, it is essential toavoid repeated sun exposure or extended. Hat, parasol, cap and sunscreen (with a minimum SPF of 30) should be recommended, especially in the summer season. Besides, a healthy diet favoring antioxidant foods (especially fruits and vegetables) and moisturizers (based on an active agent such as hyaluronic acid) are essential in order to prevent skin aging. Good sleep, regular physical activity and smoking cessation are also recommended.

While UVA rays promote skin aging, UVB rays alter the pigmentation of the skin. Indeed, UVB affects the epidermis (the surface layer of the skin), stimulates the production of new melanin, which leads to a massive increase in the quantities of dark pigments. While UVB rays provide a long-lasting tan, they can also cause skin hyperpigmentation.

Hyperpigmentation is characterized by the appearance of more or less dark spots on one or more regions of the body. Dark or dark skin is the most at risk:

• Melasma (also called chloasma) results in dark and irregularly shaped areas on the chin, forehead, cheeks or even the bridge of the nose. It results from prolonged or repeated sun exposure, especially during hormonal changes in women. It more readily affects pregnant women (we speak of the pregnancy mask) and women who use estrogen-progestogen contraception;
• Lentigos are small rounded dark spots. They are linked to age and excessive sun exposure. They appear on the areas of the body most often exposed to the sun: face, arms, neck, décolleté or hands;
• Post-inflammatory pigmentations result in persistent brown spots that follow the healing of a skin disease such as acne. They are favored by sun exposure;
• Photoreactions to certain cosmetics or certain drugs: sun exposure can lead to the appearance of spots when taking certain drugs or when applying certain cosmetic products.

Hyperpigmentation: what to do

The first step to avoid hyperpigmentation is to apply an anti-UV cream daily to the face. Certain dermo-cosmetics make it possible to prevent and gently treat hyperpigmentation: Thiamidol, Vitamin C, Dioic Acid, Polyphenol, exfoliating agents, etc. Treatments for persistent melasma or lentigo most often involve medicated creams based on hydroquinone or retinoids. Peeling or laser can also be recommended as a last resort because these methods remain aggressive for the skin.

Actinic keratosis commonly known as “solar keratosis” is one of the leading causes of consultation with a dermatologist in France.⁽¹⁾. It is characterized by the appearance of one or more lesion (s) red (s), crusty (s), rough to the touch. This condition develops in areas exposed to the sun: skull, face, neck, arms, hands, etc.

Actinic keratosis testifies to an exhaustion of the solar capital of the individual and his excess of exposure to the sun during his life. The disease begins around the age of 60 and is a marker of skin cancer risk^(1). The only way to protect yourself is to protect yourself from the sun by preferring shaded areas and by wearing a hat, long sleeves and sunscreen during hot seasons.

The treatment aims to eliminate the lesions either directly in medical consultation by cold (nitrogen) or by the daily application of topical drugs. Sometimes these treatments are combined with dynamic phototherapy.

Sun: beware of burns!

UVB rays are responsible for burning the skin commonly known as “sunburn”. The latter are characterized by a rosaceous to red plaque spread over an area of ​​the body. They are often painful. When the skin is dewy, the sunburn is usually mild. However, when the plaque is red, it is a true second degree burn and when the skin turns purplish, it indicates a third degree burn. The sunburn is then sometimes associated with blisters.

Generally, the sunburn disappears spontaneously (on condition of avoiding any exposure to the sun) over a period varying from a few days to a few weeks or months in the most serious cases. The skin then eventually flakes and it is then recommended to opt for SPF 50 protection in order to avoid relapses. Fair skin is particularly at risk of sunburn.

Be careful, sunburn should not be confused with benign summer lucitis (or sun intolerance). Like sunburn, it is linked to excessive sun exposure. However, it differs from it by its clinical picture since it presents red patches accompanied by small itchy pimples.

UV as a risk factor for skin cancer

Carcinomas represent 90% of skin cancers⁽²⁾ and generally strike from the age of 50 and on areas most exposed to the sun. Melanoma, a more aggressive form of skin cancer, can affect young adults. A study published in Cancer Epidemiology, Biomarkers & Prevention⁽³⁾ has shown that women who have suffered at least five sunburns with blisters before the age of 20 have an 80% higher risk of developing melanoma than those who have not had this type of accident. The conclusion of this work was that while the accumulation of UV doses over the course of life increases the risk of carcinoma, the risk of melanoma is more associated with sunburn in youth.

Did you know that the sun is the first risk factor for pigment spots but also for premature aging? In order to avoid these inconveniences, it is recommended to opt for a beauty routine including anti-UV, moisturizing and depigmenting agents.