Photoaging

[3]: 29 UVB rays are a primary mutagen that can only penetrate through the epidermal (outermost) layer of the skin and can cause DNA mutations.

UVB can cause the formation of freckles and dark spots, both of which are symptoms of photoaging; these are most common in people with fair or light skin.

[7] With frequent long-term exposure to UVB rays, signs of photoaging might appear and precancerous lesions or skin cancer may develop.

However, with constant UVA exposure, the size of the dermis layer will be reduced, thereby causing the epidermis to start drooping off the body.

[citation needed] It has been reported that UV radiation leads to local and systemic immunosuppression, due to DNA damage and altered cytokine expression.

The Langerhans cells may undergo changes in quantity, morphology, and function due to UV exposure and may eventually become depleted.

One proposed explanation for this immunosuppression is that the body is attempting to suppress an autoimmune response to inflammatory products resulting from UV damage.

This entire process is aided by the presence of reactive oxygen species that inhibits protein-tyrosine phosphatases via oxidation, thereby resulting in the up-regulation of the above-mentioned receptors.

Photodamage can also be characterized as a disorganization of the collagen fibrils that constitute most of the connective tissue, and the accumulation of abnormal, amorphous, elastin-containing material, a condition known as actinic elastosis.

It has been reported in many cases that fairer individuals who have lesser melanin pigment show more dermal DNA photodamage, infiltrating neutrophils, keratinocyte activation, IL-10 expression and increased MMPs after UV exposure.

The skin contains several antioxidants, including vitamin E, coenzyme Q10, ascorbate, carotenoids, superoxide dismutase, catalase, and glutathione peroxidase.

[12] Secondary protection refers to early detection of disease, potentially while still asymptomatic, to allow positive interference to prevent, delay, or attenuate the symptomatic clinical condition.

This includes the following: retinoids (e.g. tretinoin), antioxidants (e.g. topical vitamin C, oral supplements, CoQ10, Lipoic acid), estrogens, growth factors and cytokines.

Tretinoin, a retinoid, is widely considered to be the most efficacious treatment for photoaging by dermatologists due to consistent evidence from several randomized clinical trials.

Binding to these receptors induces a cascade of cellular processes that ultimately lead to increased collagen production and epidermal thickening, reducing the appearance of skin sagging and wrinkling.

[14] Lastly, tertiary prevention is the treatment of an existing symptomatic disease process to ameliorate its effects or delay its progress.