The sun and your child's skin

The sun emits radiation that penetrates the skin. Essential to our good health, these rays can also cause harmful effects for the body. And when faced with UV rays, a child's skin is more fragile than that of an adult: it defends itself less well against the sun's attacks and retains the “memory” of sunburn for many years. Childhood is therefore a key period facing the sun, and parents have a major role to play in preserving their child's skin. Learn with us to better understand the dangers of the sun and the ways to effectively protect your baby! SOLAR RADIATION The different radiation Among the solar radiation that reaches the Earth, there are three types of radiation having effects on the body: • visible radiation (what the human eye perceives), • infrared (IR), • ultraviolet (UV): UVA and UVB. The ozone layer stops UV rays whose wavelength is less than 290 nanometers (UVC) and the shortest UVB (280-290 nm). Effects on the skin The effects of radiation on the skin vary depending on their wavelength: the longer the wavelength of radiation, the deeper it penetrates into the skin. Thus, UVA and UVB have different consequences: • UVB is responsible for tanning, sunburn, skin aging and skin cancer. They are harmful to the skin. • UVA rays, which penetrate deeper, are responsible for tanning but also for aging and wrinkles in the skin. UVA rays are less energetic than UVB rays, but they are much more abundant: they represent 98% of UV, compared to only 2% for UVB. Moreover, they are constant throughout the day and throughout the year, while UVB is strong at midday and in summer, but weaker in the morning, evening and in winter. Good sun protection must therefore be active against both UVA and UVB rays. Radiation received The amount of solar radiation received by the skin varies depending on many factors: • The season: in July in the northern hemisphere, the risk of sunburn due to UVB is 100 times greater than in winter.• Latitude: the intensity of the sun is maximum at the equator where the radiation is vertical and therefore has a shorter path through the ozone layer.• Altitude: the amount of UVB increases by 4 % for every 300 meters of elevation. This partly explains the major risk of sunburn in the mountains. • The time: in the morning and evening, the radiation is oblique. It crosses more of the ozone layer between 11 a.m. and 2 p.m.: UVB radiation is then at its maximum. • Clouds: depending on their thickness and their altitude, they can filter UV rays a little but a sunburn is always possible under a hazy sky. • The nature of the ground: the power of reflection is different depending on whether it is snow (85%), sand (17%), water (5%) or grass (3%). Thus, the mountain combines all the dangers with more UVB because of the altitude, and more reflection on the snow. • Water: this reflects up to 20% of UV rays, hence a risk from sunburn, including underwater.THE EFFECTS OF THE SUN ON THE SKINThe positive effects The sun's rays cause positive biological reactions, the main one of which is the synthesis of vitamin D. This vitamin stimulates calcium metabolism and promotes growth bone. The sun also has a beneficial effect on morale, and it can, for example, be used to prevent seasonal depression. Negative effects However, solar radiation also has harmful biological effects, both in the short term and in the long term: - In the first hours following exposure, two types of phenomena can appear, depending on the duration and intensity of the exposure and phototype of the subject: • The caloric effect due to infrared can lead to sunstroke, with discomfort and/or headaches, or even heat stroke, with acute dehydration and impaired consciousness. This occurs especially in children. • The epidermis can be burned by UVB, and partially by UVA, and a sunburn can then appear. - After several years, repeated exposures without appropriate effective protection can lead to deterioration of skin cells: • UVA accelerates skin aging and causes the destruction of the elastic fibers of the skin. • UVB, with the help of UVA, induce skin cancers through the mechanism of photocarcinogenesis. We distinguish between epitheliomas, which appear in the form of small rounded whitish or pinkish growths or persistent crusts, and malignant melanomas, appearing on healthy skin or resulting from the transformation of a mole. To detect these melanomas early, you must be attentive to any mole that changes in appearance in shape, color or thickness and do not hesitate to regularly consult a doctor. UNEVEN SKIN TYPES FACING THE SUNFacing Exposure to the sun, the skin implements natural biological defense reactions. The stratum corneum thickens and cells called melanocytes produce a natural pigment, melanin, which gradually colors the skin: this is tan. But not all skin is equal to the sun: depending on its ability to produce melanin and therefore to tan, it is more or less resistant to UV rays. We can thus determine six different phototypes: Phototype Hair Complexion Tan Freckles Tan I Red Milky +++ Constant + 0II Light Blonde ++ Constant Light Tan III Blonde/Brown Light Matt + Frequent Light or Dark Tan IV Matt Brown 0 Rare Dark Tan V Matt Brown 0 Exceptional Very darkVI Matte Black 0 Absent Black