How the sun affects skin



While most people love the sun, not many people are aware of the damage it causes to skin. Exposure to sun in the short term is of limited consequence but prolonged exposure to sun can lead to premature aging, development of skin cancer and formation of wrinkles and photo aged skin. Harm from the sun is due to exposure from ultraviolet light (UVA and UVB). In the past, it was believed that skin fragility, easy bruising, and wrinkling were simply due to aging - we now know that prolonged exposure to sun can cause premature development of many skin changes. UVB rays from the sun typically affect outer layers of skin, including the epidermis. UV light rays are particularly intense from 10.00 am to about 3 pm. These rays are even more pronounced during the summer months. Unlike UVB, UVA rays can penetrate much deeper into the skin and cause a lot of damage. The greater the exposure to UVA rays, the more intense is the damage. Unlike UVB rays, UVA rays are not filtered by glass. Continued exposure to the sun leads to skin damage that may result in appearance of wrinkles, fine lines, photo aged skin and skin cancer. It is believed that these ultraviolet rays break down collagen and other tissue substances and interfere with DNA repair. In addition, there is irreversible damage to elastin which makes the skin becomes saggy, and there is production of free radicals that may play a role in the generation of skin cancers. When collagen synthesis is impaired, this results in disorganized collagen fibrils that result in development of solar spots. Over time, repeated damage to collagen fibers leads to lose of structural support and development of wrinkles. There is also recent evidence that prolonged exposure to sun’s UV rays can lead to impaired immunity. Cells which protect the skin are damaged by the UV light and this results in more damage and cancer formation.

When sun exposure is intense, the first finding is that of changes in skin texture. The skin starts to become rough, wrinkled, and has little elasticity. Over time, skin discoloration appears which is often known as freckles, liver spots, or solar spots. These skin discolorations may appear over the back, chest, shoulder, arms, and upper back. Many individuals notice that even the slightest trauma to skin leads to easy bruising and tearing. This is most common around the arms and neck.

There is no question that prolonged sun exposure leads to skin cancer. Initially one may develop early cancerous lesions like actinic keratosis-, which are most common on the face, neck, ears and back of hands. Other sun related skin cancers include squamous cell cancer, basal cell cancer and the dreaded melanoma.

The best way to prevent harmful effects of sun is to avoid intense exposure of sun in the first place.