The skin has many important functions. It protects us from disease, injury and changes in temperature.
The skin has two main layers. The outer layer is called the epidermis. It contains basal cells and squamous cells, which link tightly together to form a barrier, and melanocytes, which produce melanin, the substance that gives the skin its colour. The layer underneath the epidermis is called the dermis. The dermis contains the roots of hairs, glands that make sweat and oil, blood and lymph vessels and nerves. Below this is a layer of fat.
What happens to the skin in the sun?
Each time your unprotected skin is exposed to ultraviolet (UV) radiation, it causes changes to take place in the structure of the cells and in what they do. Over years of exposure to UV radiation, the skin becomes permanently damaged. The damage worsens with more UV radiation exposure.
These changes are often described as “premature ageing”, but they are, in fact quite different to normal ageing in the skin. In old age, the skin that is not exposed to the sun is smooth, without spots or blemishes. It is a little thinner than younger skin, but there are relatively few wrinkles and it remains fairly firm.
Skin that has been exposed to the sun, on the other hand, becomes thickened, rough and leathery. Gradually, over 20 to 40 years, it acquires many blotches and blemishes and fair skin particularly may become yellowish. It becomes loose, and it is covered with fine wrinkles broken by a number of deep creases. These effects are seen especially on the skin that gets the most sun – the face, the back of the neck, the backs of the hands and the arms and neckline.
The changes to your skin from sun damage range in a spectrum. At one end of the spectrum is what can be called photodamage where there may be a change in the colour (pigmentation and redness), contours (wrinkles) or texture (dry, roughened skin) of the skin.
More severe sun damage may then manifest as skin cells damaged to the extent they are more likely to develop into skin cancers. These precancerous areas of skin are commonly called sunspots but medically are termed solar keratoses. The most serious level of sun damage to the skin is when the skin develops cancerous growths i.e. skin cancers.