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What does solar radiation do to your skin

The skin uses sunlight to help manufacture vitamin D, which is important for normal bone formation. But sometimes it's ultraviolet light can be very detrimental.

Within the skin's outer layer are cells that contain the pigment melanin. Melanin protects the skin from the sun's ultraviolet rays, which can burn the skin, and over time, could reduce its elasticity and causes premature ageing. Sun tanning occurs as a result of exposure to sunlight. The skin then produces more melanin and darkens. The tan fades as these cells move toward the surface and are sloughed off.

Too much exposure to ultraviolet or UV rays can cause sunburn as UV rays penetrate the outer skin layers and pass into the deeper layers, where they can damage or kill skin cells. People who do not have much melanin should protect themselves by covering up sensitive areas, wearing sunblock and limiting their total exposure time.

Frequent and prolonged exposure to ultraviolet rays over many years is the chief cause of skin cancer, and for this reason, it is important to examine skin regularly for the development of suspicious growths or changes that make occur in the skin. Early detection and treatment are key to increasing the cure rate for skin cancer.

How does solar radiation cause skin cancer, photo-ageing, and damage to the skin?

Skin is composed of three layers: the epidermis, or outermost layer; the dermis, or middle layer; and the basement layer. The dermis contains collagen, elastin, and other fibres that support the skin's structure. It is these elements that give skin its smooth and youthful appearance and that are damaged by UV radiation (UVR).

The UVR that affects the skin is composed of two different types of waves, UVA and UVB. When UVR hits the skin, cells in the dermis scramble to produce melanin to the epidermis. This is the process that gives you a tan, which is really just your skin attempting to block the radiation from penetrating your skin.

Most skin cancers are a direct result of exposure to the UV rays in sunlight. Both, basal cell and squamous cell cancers (the most common types of skin cancer), tend to be found on sun-exposed parts of the body and is typically related to lifetime sun exposure. The risk of melanoma, a more serious but less common type of skin cancer, is also related to sun exposure, although perhaps not as strongly. Skin cancer has also been linked to exposure to some artificial sources of UV rays.

UVB rays are shorter than UVA rays, and are the main cause of sunburn. But it is the UVA rays with their longer wavelength, that is responsible for much of the damage we associate with photo-ageing. UVA rays penetrate deep into the dermis, where they damage the collagen fibres. This damage causes increased production of abnormal elastin. The unusual amounts of elastin result in the production of enzymes called metalloproteinases. These enzymes, which rebuild damaged collagen, often malfunction and degrade the collagen, resulting in a compromised skin barrier. As this process is repeated with daily UVA exposure, the skin forms wrinkles and the depleted collagen results in leathery skin.