Understanding the physiological processes that cause skin ageing can allow us to better address skincare needs and deliver optimal treatment outcomes.
Skin ageing itself does not affect a person’s life span, however it can affect the way they perceive themselves and can even have a negative impact on their relationships with others.
Ageing skin is easily recognised: loss of elasticity, sagging jowls, wrinkles and the appearance of parchment-like skin. There are two main processes of skin ageing: intrinsic and extrinsic. Intrinsic ageing is involuntary and reflects the genetic background of the person whereas extrinsic ageing is caused by external factors such as sun exposure, poor nutrition, smoking and alcohol. Extrinsic ageing is implicated in premature ageing and one of the most common causes of extrinsic ageing is the damage caused by the sun.
Ageing manifestations
Scientific research has found keratinocytic dysplasia and accumulation of solar elastosis results in cutaneous carcinogenesis of the extrinsically aged skin. Unfortunately extrinsic ageing superimposes itself on intrinsic ageing and therefore it becomes impossible at times to separate these two processes of ageing.
The sun is a major contributing factor to extrinsic ageing, causing photodamage as a result. There are numerous signs of photoageing that are fundamentally related to a person’s skin colour and more importantly their exposure to the sun. The latter can be controlled and education about sun damage and skin cancers is therefore vital. Most schools begin this education in a person’s primary years with the hope that this information will be consistently adhered to throughout their life. Unfortunately, tanned skin is perceived to be ‘healthy’ by many people, and sunbaking and visiting tanning solariums puts their health at a significant risk.
Skin ageing is apparent through the manifestations of telangiectasia, skin wrinkling, leather-like dry skin, lentigenosis and hyperpigmentation. Collagen in the dermis becomes calcified, leading to deep lines and furrows and wrinkling of the superficial skin. Comprehensive recommendations for sun protection to prevent premature ageing caused by the sun includes:
- Avoiding deliberate tanning, including solariums
- Avoiding the sun when it is at its strongest during the day, between the hours of 10am and 4pm
- The use of protective clothing such as a wide-brimmed hat, long sleeves and wearing swimsuits made of fabrics that deflect the sun’s harmful rays.
- Always wearing sunscreen which is broad-spectrum based (UVA and UVB) and has a built-in sun protection factor of minimum SPF 15. This should be applied 20 minutes before going out in the sun and then re-applied every two hours, depending on the circumstances.
Other factors of extrinsic ageing are related to poor health and inadequate nutritional diet, lack of exercise, alcohol abuse and cigarette smoking, varying degrees of subjective stress and poor posture leading to kyphosis (spinal problems).
Additionally, continual repetition of facial expressions can lead to the development of wrinkling, and poor sleeping habits and habitual specific sleeping positions over many years contribute to ‘sleep lines’.
Extremes of environmental conditions such as cold and heat assists in the depletion of trans-epidermal water loss, causing to the skin to become dry and dehydrated, The salient point to note however is that extrinsic ageing can be modulated and delayed by the personal choices and judgments a person makes on a daily basis.
Scientific research has found that examination of the intrinsically aged skin under a microscope revealed ‘epidermal atrophy, flattening of the epidermal ridges and dermal atrophy’. Intrinsically aged skin displays an increase in the number of collagen fibrils (not thickening) and this is especially evident in the increase of collagen type III to collagen type I ratio. Age-related changes occur throughout the epidermis, dermis and hypodermis (subcutaneous tissue,) resulting in a host of changes in the topography of the skin.
The effects on the stratum corneum
Other studies find that the stratum corneum in the epidermis does not become thinner but there is an increase in scaling (sloughing off) of the cells in this layer. Because the rate of cellular division is slower in the elderly, the dead skin cells which are lost are not readily replaced. This important factor in slow cell replacement in the epidermis leads to the epidermis becoming compromised and therefore its susceptibility to increased permeability of allowing substances to pass through is enhanced.
The effect of ageing on melanocytes and collagen
Recent evidence suggests that there is a reduction in the number of melanocytes between 8 and 20 percent per decade as one gets older. This reduction contributes to the greater risk that the elderly have for sun-induced cancers because the healthy melanocytic activity absorbs the carcinogenic ultraviolet light, which affords each of us protection from the sun. Additionally, as one ages, the number of Langerhans cells which are responsible for skin immunity also diminishes.
The ageing dermis is characterised by marked changes in collagen production as well as the development of cross-linkages of elastin fibre thus leading to the appearance of the dermis becoming thinner and translucent. The collagen in the elderly is seen as thickened fibrils that appear to be ‘larger and coarser’. The presence of calcified collagenous fibres in the elderly leads to the significant appearance of wrinkles on the skin. This is due to the fact that collagen provides the tone and mechanical stability of the dermis and because collagen becomes calcified with age, there is a loss in bonding strength between the epidermis and the dermis leading to the wrinkling of the skin.
Loss of skin elasticity and resiliency increases with ageing. This is due to the fact that the ageing elastic fibres undergo the chemical process of cross-linkages and become somewhat calcified in this process. The outward appearance of cross-links is seen in the sagging skin of the elderly. Other changes in the dermis reflect the gradual atrophy of the sudoriferous glands and the sebaceous glands .This leads to the elderly having a much drier and scalier skin. The aged skin demonstrates increased trans-epidermal water loss (TEWL) and is therefore susceptible to becoming dry in low humidity environments. As mentioned earlier, the epidermal barrier is compromised resulting in a higher rate of permeability of substances into the skin as well as abetting the reverse process of water loss from the skin.
Furthermore, the elderly also lose their ability to regulate body temperature and are therefore adversely affected by heat exhaustion. Some other notable changes in the elderly include the ‘greying of hair’ due to the decreased number and activity of the hair follicles as well as the gradual loss of pigment from the hair. There is also thickening and the development of ridges on the nails due to increasing deposition of calcium as well as loss of sensitivity to touch where there is a loss of hair on the skin.
Ageing and the hypodermis
In the hypodermis, the elderly skin displays both a loss and gain of subcutaneous tissue, which is site specific. The face, shins, and hands show a reduction in subcutaneous fat while the waist in women and the abdomen in men have accumulated deposits of fat. Where the subcutaneous fat is lost, together with a loss of blood supply, there are chances that the elderly bedridden persons will develop bedsores especially where the skin passes over the protruding bony areas and is subjected to pressure.
The elderly also exhibit a lower body temperature because the loss of subcutaneous fat also allows heat to be lost through the skin surfaces. This is one of the reasons why the elderly person feels the cold and puts on layers of clothing when in actual fact it may be a warm day.
Treatment objectives
Skin rejuvenation objectives should include four key areas:
- Protection against environmental ageing For example, the use of sunscreens for sun protection, supported by serums that also give the skin added support against solar ageing should be our first line of defence. These include a combination of Vitamins C and E as scientific evidence suggests that these two nutrients when combined offer added defence against sun damage.
- Protection against transdermal water loss Ensuring appropriate hydration levels will enhance the skin and retain its youthful appearance. In fact, if the skin is dehydrated this will compromise the skin’s ability to absorb and respond as effectively to your rejuvenation treatments. Therefore, maintaining optimum hydration levels in the skin is paramount to the success of your treatments.
- Exfoliation As the skin’s exfoliation process slows down with ageing, effective removal of dead skin through appropriate mechanical or chemical means will support the skin’s renewal process and allow for better penetration of active ingredients. However, this must be achieved, while still protecting the integrity of the stratum corneum.
- Support collagen production As collagen is the building block of the skin and responsible for keeping the skin dense and firm, procedures that stimulate collagen production and support its integrity should also be the cornerstone of any treatment when addressing skin ageing.
When skin therapy treatments are based on a thorough understanding of how the body ages and the resultant manifestations, the root of the problem can be addressed to achieve results that offer real solutions.
