Photoaging – When the sun marks the skin
Covering an area of 1.5–2 m2 and weighing 3.5–10 kg for an adult, the skin is the largest organ of the human body. The skin protects the body against heat, light, injury, and infection. It regulates the body temperature through sweating, and it can store water and fat. Various endogenous and exogenous factors can have a detrimental effect on the skin’s condition and appearance, and thus on our wellbeing.
Warming sunrays make us feel more comfortable and natural UV light is indispensable for the production of vitamin D. But light and the sun also have their downsides. If exposed to the sun for too long, the skin is put under enormous stress, becoming strained or even burnt, and our skin does not forget this stress – not one sunbeam, and definitely no sunburn!
UV rays, especially UV-A, accelerate the aging of skin and are one of the main causes of skin cancer.
Photoaging – Cause/Origin
The skin can be categorized into three layers: the epidermis, the dermis and the subcutis. The epidermis is the outermost, visible part of the skin and includes the stratum corneum, which is mostly made up of keratinocytes (cornifying cells) and is being constantly renewed in a process of shedding and rebuilding. The dermis consists of a dense network of elastic and collagenous fibres that give the skin its tensile strength and elasticity. It is these elements that lend the skin its smooth and youthful appearance. The subcutis consists of connective tissue and fat cells, and serves as an insulating barrier and energy store.
The UV radiation our skin is typically exposed to comes in two different waveforms: UV-A and UV-B. When UV radiation strikes the skin, the melanocytes in the dermis are incited to produce melanin in order to protect the cell nucleus against DNA damage. This process gives the skin a tan, which helps to block more radiation from getting in.
UV-B rays are short-wave rays that penetrate into the epidermis and cause sunburn. But it is the UV-A rays, with longer wavelengths, that cause the majority of skin damage and are therefore principally responsible for photoaging. UV-A rays penetrate deep down into the dermis where they cause the formation of reactive oxygen species (ROS) and thus induce inflammatory processes. Most noteworthy is the formation of matrix metalloproteases, which lead to the degeneration of collagen fibres. These induced processes ultimately result in premature skin aging.
Photoaging – Consequences
When constantly exposed to sunlight and thus to UV-A radiation, especially in the exposed areas of the face, hands and arms, the skin’s protective barriers and mechanisms are weakened. Inflammatory processes accumulate, resulting in atrophy of collagen fibres and actinic elastosis. The result is a decline in skin volume and density, which manifests as slacker skin.
As we age, the skin’s natural production of hyaluronic acid also drops, meaning the skin gradually loses its capacity to store any moisture it has managed to collect. By inhibiting and disrupting the skin’s normal hyaluronic acid production, chronic photodamage (light damage) also disrupts the water binding capacity. The skin becomes dry and the texture becomes rougher and more defined by fine lines, large pores, and even wrinkles and deep creases.
Further consequences are hyperpigmentation, lentigo solaris (liver spots), vascular changes like telangiectasias, actinic purpura, hyperkeratosis, and actinic keratosis, which is ultimately a preform of squamous cell carcinoma.
These factors and visible signs of sun-induced aging can and should be avoided.
Photoaging – Prevention
The first thing is to limit sun exposure and avoid going out during the critical times (midday hours). Shade and the right clothing generally offer good UV protection, but sunscreens are indispensable. Daily sun protection (>SPF 15) of the exposed areas of the face and body reduces the effects of photoaging and lowers the risk of precancerous conditions.
Cosmetic care products should thoroughly moisturize and stimulate the skin’s synthesis of hyaluronic acid, and should also protect and build up the skin’s lipid barrier. ROS-binding actives capture and bind free radicals, thus preventing the initiation of inflammatory processes. As a priority, the choice of care products ought to actively inhibit the breakdown of collagen and elastin structures in the skin.
In addition to classical cosmetic care products, special care products with higher concentrations of actives (have a look at the blogpost dermocosmetics and cosmeceuticals) can eliminate and control specific skin problems such as pigmentations. Combining this with device-based treatments such as mesotherapy, microneedling, lasering, IPL, radio frequency, dermabrasion & chemical peels, Botox, and fillers can help photodamaged skin to recover a firmer, fresher and more youthful appearance again.
An effective way to combat photoaging and to eliminate its effects is to minimize exposure to UV light and to use sunscreens all year round. Photoaged skin can be treated by a diverse range of cosmetic measures (care products, cosmeceuticals, and device-based cosmetics).
- Dr. med. Harald Gerny (2014): Fachbuch der medizinischen Kosmetik 1st Edition, ISBN 978-3-906112-32-9
- Dr. med. Nicole Menche (2011): Biologie, Anatomie, Physiologie 7th Edition, ISBN 978-3-37-26802-1
Once burnt, twice shy – after one too many severe sunburns, I learned at a young age to protect and care for my skin. Today, I am a strong advocate of SPF 50+ suncare products and early anti-aging care.
As a user of cosmetic products, I avidly follow the current trends. As a cosmetic chemist, I am all about the latest raw materials and active ingredients. And as a medical cosmetician, I am passionate about helping patients achieve a beautiful, healthy skin with visible results.