Factors Affecting Skin Function
Environments that dehydrate the skin can considerably affect the skin condition, and hence its functions. Examples include centrally heated and air-conditioned homes and offices.
Out of doors, sun and wind together may produce very severe drying effects, especially if they are experienced over a long period of time.
Water and harsh household detergents and cleaning fluids are the most damaging factors of all, particularly to the hands. People who work as cleaners or apprentice hairdressers expose the skin of their hands to water and chemicals all day long, almost every day. This can result in chronically dry and chapped hands, which may result in a form of irritant dermatitis if left untreated. In turn they may become prone to develop allergies to products with which they come into contact, producing an allergic dermatitis.
Climate and skin condition
Climate can make a considerable difference to the state of all our skins. Where we live in the world, and whether we are adapted to the local climate there, may also be critical.
The humidity of the air is important to the way we feel and how our skin condition fares. Humidity is largely determined by temperature: this is because the air can hold more water vapour at higher temperatures. In winter the air cannot hold as much water, and on a very cold day there is virtually no moisture in the air at all. This is why we can often see people's breath in frosty weather: as the warm, moist air from the lungs cools down, the water vapour in it turns into tiny liquid drops that form clouds.
In hot weather, most of us find dry air more comfortable and pleasant than very humid air. The tropics are hot and humid, while Scandinavia can be warm and dry. Many people find hot, humid weather trying and difficult to tolerate: this is the kind of weather in which, in certain countries, seems to accentuate a tendency for riots to break out! The skin, however, prefers humidity to dryness.
Skin condition in winter
The condition of skin can change from day to day, and even from hour to hour. It may be affected by general health, by changes in hormones during the menstrual cycle and by the immediate environment. Skin that felt normal in the morning may feel greasy and uncomfortable after a day spent travelling in crowded trains and working in an office with rather inefficient ventilation.
Skin needs to maintain water balance with the environment for ideal function. As we have seen, the epidermis, particularly the stratum corneum, acts as a partial water barrier, helping to regulate the amount of water in the skin. This barrier itself needs adequate water (more than 10%) to function properly.
This water is used to ensure that the other vital part of the barrier, the lipid structures between the cells of the stratum corneum, is maintained in a fluid state. Damage to the stratum corneum - for example, by washing with harsh soaps, which removes both external and internal lipids - can disrupt this barrier and set up a 'vicious circle' of drying.
Dry Skin in Winter
In fact, skin has to fight a daily battle against the drying effects of the environment.
But this drying effect is worse in the winter months. Although air in the winter months often feels damper, on average it has less relative humidity than in the summer - that is, humidity compared to that of the skin.
In winter the difference between the concentration of water in the air and that in the skin exerts a considerable drawing force on water in the skin. If dry skin becomes drier, the lipid structure of the barrier tends to break up. As a result, water cannot be retained so easily. The cycle of water loss is set up again.
Another factor is that the stratum corneum simply doesn't like the cold. Cold makes keratin stiffer and less flexible - you will probably be familiar with the 'tight' feeling that skin has in the winter.
As a result of all these factors, skin tends to be drier and in worse condition in the winter months than at other times of the year. In extreme cases, this constant drying effect can lead to cracking, flaking and redness. In the winter, skin tends to lose the battle against the environment. That's when it needs to be looked after most.
In the winter, a moisturizer can be regarded as essential to maintain healthy skin - even so-called 'normal' skin. As we will see later, a moisturizer performs several important functions. It enables lost water to be replaced, and then helps to keep it in the skin by the humectants (water-binding agents) that it contains (see Moisturizers). One such is glycerol. Scientists have shown that humectants play a vital role in the skin by helping to maintain the lipids of the epidermis in good condition, vital to its water-retaining properties.
A good moisturizer will deliver water to the skin effectively and keep it in the skin for as long as possible.
Coming in from the cold
Coming into a warm room from the cold outdoors will often restore a rosy glow to the skin and soften it to some degree. This is due to the blood vessels in the skin opening up in the warmth.
This will not help to restore moisture, however. It may even encourage more water loss, since the air in centrally heated houses is often drier than that outside!
Sebum production in winter
Sebum (the lipid mixture produced by the skin's sebaceous glands, see Special Skin Structures) is produced at a fairly constant rate in each individual, though rates vary from one person to another and tend to be higher overall in the teenage years. It does not change in response to time of day or season, though sebum will obviously build up on the skin throughout the day. (This is why skin feels sticky at the end of the day.)
Since sebum production is neither significantly lower or higher in the winter, there is no need to use a moisturizer with extra (or less) 'oil' in the winter to compensate for a lack (or excess) of sebum.
Skin appearance in winter
As we have seen (The Layers of Skin), the skin's response to cold is to close down the small blood vessels in the dermis. This diverts blood from the surface of the body to the inside, and helps to check heat loss.
The result can be that in cold weather skin loses the glow it normally gains from blood flow close to the surface, and it can tend to look dull and lifeless. Massaging with a moisturizer will help to stimulate circulation near the surface and give the skin more color, as well as improving the water content. You can do this as often as you need to - you can't over-moisturise!
Some people have a particular sensitivity to even slight drops in the air temperature, resulting in the ends of their fingers going white. This is called Raynaud's phenomenon: although it can be painful it is otherwise harmless.
The essentials of winter skin care
- Use a good moisturising product during the day - it doesn't need to be a heavy cream, but it does need to hydrate well. Use it liberally and often.
- At night, use a good night cream. Night creams are specially formulated with a higher lipid content than would normally be comfortable in the day, to help restore softness to the skin.
- Do not wash with harsh soaps. Soaps dry the skin and exaggerate the effects of the cold. Use a good-quality mild cleanser formulated for 'sensitive' skin.
- Stay warm! Keep well wrapped up, to help maintain a soft skin by preventing excessive TEWL.
