Guest post by: Jane Neville Dudik, Acne Treatment Center
Years ago I had a friend who was a medical imaging technician.
He enjoyed his profession and was able to get his license plate to say “Imaging.” He was proud of that plate until his wife pointed out that it really said “I’m aging.”
I got a perverse kick out of the fact that that plate faded in the sun.
Last time I told you all about what the shorter wavelength, UVB does you your skin.
UVA, the skin's secret enemy
UVA are the longest wavelengths (320 – 400 nm) before you get to visible light. Because they are longer, they are less powerful.
Years ago, when I was a child, scientists did not think UVA did any damage to the skin because they don’t usually lead to sunburn. But a lot has been learned in the intervening years.
As more has been learned, they have begun subdividing UVA into:
- UVA I (320-340 nm)
- UVA II (340-400 nm)
This matters when we get to discussing sunscreen in Part 3.
Because UVA wavelengths are longer, they penetrate further.
They penetrate through clouds, so if you live in a cloudy place as I do, you may think you are in no danger from the sun. You'd be wrong.
They penetrate through the layers of atmosphere when the sun is at any angle, including before 10 in the morning and after 4:00 in the afternoon.
If the sun is above the horizon, you are dealing with UVA
One of my mentors likes to remind people that if the sun is above the horizon, you are dealing with UVA.
UVA rays penetrate through glass. When you are driving in your car or sitting by a window, you are bathed in them.
And they penetrate through your epidermis into your dermis where they do a bunch of damage.
On their way through the bottom (basal) layer of your epidermis and the top layer of your dermis they stimulate your melanocytes to produce melanin, which is how you become tan.
Many people think of a tan as healthy, but it is actually an immune response.
Your body is trying to protect the DNA of your skin cells from the ravaging effects of the sun, so it covers them with pigment to reflect away the UV.
The pigment-producing melanocyte is a dendritic cell, which means it is shaped kind of like your hand.
The melanosomes are little pearls of pigment produced in what would be your palm and run down and off your fingers and cover all the surrounding cells.
Dark skin vs Light skin
Someone with very light skin has the same number of melanocytes as someone with very dark skin, but the dark skin melanocytes produce many more of these pearls of pigment.
How liver spots form
The more your skin is exposed to UVA, the harder these hand-like cells have to work, and eventually they get tired and the fingers begin to deteriorate.
The palm is still producing the pigment, but now it has no way to spread it out to the surrounding cells, so it leaves a concentrated blob. Eventually you see this concentrated blob as a 'liver spot' which has absolutely nothing to do with your liver.
Sometimes the melanocyte gets so tired the palm stops producing pigment and you are left with a little white spot that we call hypopigmentation.
Can you handle some more geekiness?
Your dermis and epidermis are joined very securely at the dermal junction by ridges projecting down from the basal layer of the epidermis into the dermis called reté pegs and bumps in the dermis projecting up into the epidermis known as dermal papillae.
In fact, the top layer of the dermis is called the papillary dermis because of these bumps.
These papillae have tiny blood vessels running through them. There is no blood supply in the epidermis. The epidermis gets its nutrients and oxygen from the blood vessels in these papillae.
Okay, back to our friend UVA...
As the UVA has penetrated to the dermal junction it causes the dermal papillae to flatten out and the blood vessels they contain to become more visible.
How do you get 'broken capillaries'?
If you remember, one of the effects of UVB is severe dilation of blood vessels. You combine repeated dilation of blood vessels with the flattening of the papillae and you get the visible tiny blood vessels known as telangiectasia, or as your mom would call them “broken capillaries.”
The greater the cumulative sun exposure, the more the papillae flatten.
The more they flatten the more tenuous becomes the dermal junction.
As it breaks down you will see the classic wrinkling of old age – which is sun damage. Eventually the junction become so insecure, the epidermis slips off with the least friction and the skin abrades and bruises very easily.
My dear mother-in-law loved the sun, and in her later years her skin would come off so she would bleed just by pulling on her clothes.
Why your skin begins to sag and wrinkle
Once the UVA rays have gotten down into your dermis, they cause you to produce extra collagenase, the enzyme our body produces to eat up dead collagen.
With that abundance, there isn’t enough dead collagen to keep it busy, so the collagenase starts attacking living collagen. With the breakdown of living collagen, your skin begins to sag and wrinkle.
The secret enemy isn’t done yet. UVA also damages your fibroblasts through the formation of free radicals.
Free radicals are those pesky oxygen atoms that have lost an electron and go scavenging for a replacement.
This process creates what is called oxidative stress, which is hell on all your skin cells, but particularly bad for your fibroblasts. Some maintain that all aging is a result of oxidative stress.
Fibroblasts are the cells that create collagen, elastic and glycosaminoglycan.
These are the proteins that make skin look young.
I tell my clients to think of them as structure, stretch, and bounce. By damaging the fibroblasts, UVA makes it harder for your body to produce healthy-looking skin, at the same time as it is causing you to tear down the structure of the skin that is already there.
UVA and Cancer
But saving the worst for last, UVA also has a hand in creating melanoma, that is the skin cancer that can kill you.
I live in a place where the sun doesn’t shine for about 221 days of the year.
But we love to go outside, and we drive in our cars, and we walk and bike a lot. Because the sun isn’t shining, no one thinks about sun protection. But our overcast world is still bathing us in UVA. As a result, we have one of the highest rates of melanoma in the world.
Next time we will talk about how tanning became popular and what you can do at any age to save your skin.
Jane Neville Dudik, founder and owner of The Acne Treatment Center, is a licensed master esthetician, a certified aesthetic consultant and a certified advanced acne specialist. She also is NCEA certified in advanced esthetics. She has pursued studies with CIDESCO, the Physician’s Care Alliance, the International Dermal Institute, Educated Therapists, and The Aesthetic Practitioners’ Association. She has been privileged to have studied acne with James Fulton, MD, PhD, microneedling with Lance Setterfield, MD, and Advance Skin Analysis and Cosmetic Chemistry with the incomparable Florence Barrett Hill. She holds her Bachelor’s Degree from Duke University and her Master’s Degree from Harvard University.
Jane lives in Vancouver, WA with her husband. They have three grown sons.