Photoaging is the gradual and irreversible deterioration of collagen, elastin and other fibers that give structure to the skin and keep it smooth, caused by age and accelerated by solar radiation. Although the sun is an energy source that, among other benefits, helps synthesize vitamin D, prolonged and repeated exposure can cause serious skin damage.

This aging of the skin can occur prematurely if frequent exposure to the sun occurs. It takes place in the areas of the body most exposed to solar radiation, especially ultraviolet, which acquire an aged appearance, show deeper wrinkles and spots. In the most severe cases, the sun can cause precancerous lesions that increase the risk of skin cancer.

Photoaging is irreversible since it is part of our natural aging, but its apparition can be delayed. We can’t control genetic factors or skin color, but we can control our skin’s exposure to the sun.

What kind of solar radiation is responsible for photoaging?

The sun generates energy as a result of the nuclear fusion process that occurs inside it. This energy is transferred in the form of electromagnetic waves that propagate in all directions, called solar radiation. Of that radiation, two-thirds reach the Earth’s surface, of which about 50% is visible light that the human eye is able to pick up. The remaining half is composed of different types of radiation, which reach our skin and some penetrate it:

• Ultraviolet (UV) radiation. It constitutes only 7% of the solar radiation that reaches the Earth’s surface, but it is mainly responsible for photoaging. It is composed of three different bands (A, B and C), but the atmosphere filters most of the UVA and UVB and all of the UVC. Therefore, the UV radiation that reaches us is composed mostly of UVA rays, with a small part of UVB rays. The higher the altitude, the higher the energy of the UV radiation. UVA rays penetrate the deepest layers of the skin, causing damage to collagen and elastin fibers mainly. It may also play a role in some types of skin cancer. In contrast, UVB radiation has greater energy but affects the first layers causing skin burns and are responsible for most skin cancers.
• Visible radiation (VIS). It is responsible for 40% of the sun’s damage to the skin. This radiation weakens its protective barrier, produces spots and photoaging.
• Infrared A (IR-A) radiation. It is a dry heat that is not felt when it crosses the skin, although it is the one that goes the deepest: it penetrates up to ten millimeters and is able to increase its temperature to 42ºC. It also increases damage to the DNA of cells, the source of precancerous lesions that can lead to skin cancer.

Risk Factors

There are a number of risk factors that lead to a greater likelihood of suffering the consequences of photoaging of the skin:

• People with lighter skin. The skin of these people produces less melanin, which is the pigment that gives color to the skin and filters out solar radiation. In these people the protection against solar radiation is less.
• Advanced age. Photoaging and solar radiation exposure injuries are cumulative.
• Race. Especially related to melanin.
• Living in places where solar radiation is higher. For example, on the coast, places with clear skies most of the year or high mountain.
• People who work outside or take part in outdoor leisure activities. Especially exposure during the middle hours of the day.
• Genetic predisposition. The degree of skin aging from sun exposure can vary depending on each person, depending on their system’s ability to repair their DNA.

Symptoms of photoaging

The main symptoms of photoaging can most often be observed in areas of the body most exposed to the sun such as the face, scalp (especially in people who suffer from baldness or people with very light hair color), neck, neckline, forearms, or back of the hands:

• A dry and rough touch (Xerosis Cutis).
• Laxity and lack of elasticity of the skin.
• Thick wrinkles and grooves (deep lines).
• Irregular pigmentation. Light brown spots up to 15 mm (lentigos), freckles and moles may appear. lentigos, especially in older people, should be monitored periodically to prevent their malignancy.
• Small hair effusions.
• Elastosis. Deep grooves of the skin yellowish, especially visible on the face and back of the neck.
• Actinic keratoses. Reddish, whitish or pink, elevated, dry and sometimes crusty patches on the skin. They are a type of precancerous lesions that poses an increased risk of skin tumors.
• Alterations such as papules (small elevated lumps) and pustules (lesions similar to blisters, filled with pus).
• Bateman’s actinic purpura. Painless red spots that appear on sun-damaged skin especially on the forearms and back of the hands.
• Favre–Racouchot syndrome. It is more common in people who smoke and have high sun exposure. It manifests with comedones (blackheads) and yellowish cysts around the face.
• Melasma: they are brown spots on the face, also known as “pregnancy mask”. In some people they arise as a hyperpigmentation related to pregnancy or the taking of certain hormones. It usually disappears spontaneously at the end of pregnancy or when the hormone treatment ceases and is easy to prevent by limiting sun exposure and using photoprotectors.

In the case of chronological or biological aging, that which occurs naturally with age and that is determined by genetics, the characteristics that our skin acquires are thin, flaccid skin, pigmented in a uniform way, with superficial wrinkles and benign lesions such as small red dots (ruby dots) and seborrheic keratosis (small rounded brown spots of scaly appearance).

Phases

According to Glogau’s classification, photoaging can have four degrees:

• Mild: Most common from 28 to 35 years old. This photoaging is characterized by wrinkles and incipient lines.
• Moderate: From 35 to 50 years old. The skin shows more visible wrinkles and actinic keratoses.
• Advanced: Typical between 50 and 65. Stable wrinkles and lines that also appear at rest along with actinic lesions, keratosis and/or lentigo.
• Severe: Occurs from the age of 60 to 75. It is characterized by deep and persistent wrinkles and abundant skin lesions.

How to treat photoaging? Can it be reversed?

With the passage of time, the skin loses its ability to heal the damages caused by solar radiation, so photoaging becomes irreversible. The best weapon against photoaging and possible damages derived from it, is prevention: avoid or reduce exposure to solar radiation and properly protect your skin. Taking into account the phenotype, the UV index of the day, and the circumstances of the exposure, there are different protection measures that a person can take:

• Reduce the time you stay in the sun,.
• Resort to physical barriers such as hats and sunglasses or apply photoprotective creams

The injuries caused by solar radiation are cumulative so it is important that we accustom our children from a young age to the use of these prevention measures.

Although photoaging is irreversible, currently, there are some treatments aimed at reducing the signs of premature aging in our skin, such as chemical peeling, dermabrasion, or the use of a laser. In some cases, pharmacological substances may be used at the direction of the dermatologist. There are also depigmenting creams that your pharmacist may advise. If the damage is severe, there are various types of treatments such as implants or fillers that a person can resort to. But do not forget that the most effective measure is to create the habit of prevention from an early age.

When skin lesions appear, such as lentigo, actinic keratosis, or others that may be precancerous, it is important to consult the dermatologist to perform a treatment in that phase and efficiently prevent its progression. It is crucial not to allow time to pass in order to be able to carry out effective prevention.

In cases where there is a family history of skin cancer and especially in light-skin people, it is advisable to add as a prevention element one visit a year to the dermatologist to avoid and treat lesions that increase the risk.