Dermatologist Dr. Anne Truitt discusses photoaging: definition, causes, and how best to avoid, or at least slow down the effects of photoaging on the skin.

Definition of Photoaging:

There are two types of aging of the skin: photoaging and chronological aging.  Photoaging is the damage and subsequent aging of the skin caused by UV radiation while chronological aging is the natural aging of the skin due to time.

Let’s Breakdown the Light:

I will confine this section to ultraviolet (UV) radiation as it causes most of the damage to the skin resulting in aging and skin cancers.  UV radiation is broken down into UVA and UVB. UVC is another component of UV radiation although it does not penetrate the ozone layer of the earth.  UVA has a longer wavelength than UVB and can penetrate deeper into the skin to cause a multitude of damage and cause stress to skin cells, resulting in the telltale signs of photoaging: wrinkles, hyperpigmentation, and hypopigmentation.  UVB has a shorter wavelength penetrating the upper levels of skin, and it is more associated with causing sun burn and skin cancers.  A “broad-spectrum” sunscreen is recommended is as it covers both UVA and UVB protection.

The Cellular Level of Damage: What is UV radiation actually doing?

To name a few points of damage, UV radiation will create melanin disruption, oxidative stress, DNA damage, and autophagy impairment. (Autophagy is a vital process in which the body’s cells “clean out” any unnecessary or damaged components.) Melanin production will be increased in an attempt to protect the skin with hyperpigmentation.  There are two types of melanin: 1. eumelanin is photoprotective (although at a very low SPF level), and 2. pheomelanin is photo-unstable, promoting cellular damage and photoaging.  Oxidation stress is caused by Reactive Oxygen Species (ROS) which are formed by UV radiation.  These ROS can cause DNA damage to the mitochondria, which is the powerhouse energy source of the cell.  Damage is also done to the elastin and collagen of the skin’s dermis layer which helps provide structure and support to the skin.  Finally, autophagy is an essential cellular process that maintains cell balance.  Restriction of this autophagy by UV radiation will inhibit the clearing of cellular excess and damaged cell components.

How to Avoid Photoaging:

Sun protection. Period.  I prefer mineral based (zinc oxide) sunscreens with at least SPF 30 and 5% of zinc oxide.  Zinc oxide is reef safe and gives the best broad-spectrum protection.  It is recommended to apply 30 minutes prior to sun exposure and reapply every 2 hours or after water sports/exercising.  The sunscreen is also in addition to protective clothing, hats, and sunglasses.

The good news: research is always happening!  We are currently participating in conjunction with Derm Tech, Inc. in a study on skin photoaging.  We are currently enrolling subjects. Call us and be a part of research history: 858-292-5101.