Hello sunshine

March 27, 2018 by Shari Twigg, MD
Hello sunshine
Hi Everyone,

Today, since we are all wishing for warmer, sunny weather, I want to talk about sun protection.  Firstly, this is actually important year-round, not just in the warmer months.  We all sustain damage to the skin while driving our cars, walking from the car to our places of employment, going out to get the mail, etc.  So it’s very important to place a sunscreen on after you moisturize EVERY morning (and, “no”, the sunscreen in your makeup is not enough.)

Let’s go over the basics first.  What does SPF or Sun Protection Factor really mean?  It means the relative amount of UV(B) energy required to produce redness (sunburn) in protected skin versus unprotected.  So for instance, if your face would burn in 5 minutes without protection, and SPF 10 would protect you for 50 minutes (5 minutes x 10).

Another very important factor in protecting the skin is the amount of sunscreen that is applied to the area.  On average (for lotions), the face and neck should get about ½ tsp. amount.  The body (for average normal-weight individuals) should use about 1 oz or a shot glass full.  I bet most of you never get that amount on.  So think of it this way, if you put half of the amount on, you are truly only going to get about 50% of the noted SPF instead of the 100% of whatever SPF you choose.  So it is key to apply enough.

What SPF should I be using?  Well, the least amount that should be used is a sunscreen with an SPF of 30.  Use more if you can and reapplication is key. Apply sun-screen 15 minutes before going outside (always to face and neck in the morning no matter what), reapply after 30 minutes, then again every 2 hours.  You certainly may need to apply more often if you are in water or are toweling off, as it will come off.

Who needs sun protection?  Everyone.  Every ethnic group needs sun protection.  It helps prevent premature skin aging, skin cancers, photo damage, and post inflammatory hyperpigmentation.

There are 3 types of UV rays; two of them predominantly affect our skin:  UVA and UVB.  UVC is almost completely absorbed by the ozone.  UVA causes direct tanning without redness and is a major contributor to sun damage.  It penetrates deeper in the skin than UVB.  It is not filtered by glass.  UVA is fairly constant throughout the day, as opposed to UVB, which is more intense in the summer months and between 10 am and 2 pm.  Damage from UVA and UVB may lead to skin cancer, wrinkles, pre-mature skin aging, and lowers immunity against infection.  UVB affects the skin more superficially than UVA.  UVB is the primary agent responsible for sunburn, redness, and wrinkles.  Unlike UVA, UVB rays do not penetrate glass.

How exactly does UV cause damage?  Firstly it causes fast collagen breakdown in the skin.  When we have youthful skin, the collagen in the skin is very organized, healthy, and thickly layered.  When it becomes broken down, there is an accumulation of abnormal collagen and frankly, just decreased amounts, which causes scarring and wrinkles.  Other damaging agents of UV are free radicals, damage to DNA repair enzymes (so if a particular cell is abnormal, it may continue to produce the abnormality instead of being fixed, such as what occurs with cancer), and damage to the immune system through direct damage to T lymphocytes and Langerhans cells in the skin.

One of the key components to sun protection is using a “broad-spectrum” sunscreen.  What is that?  Well, we are just talking about sun-screen agents that protect through a high level of UVA and UVB rays.  UVA wavelength is 320-400 nm, while UVB ranges around 290-320.  Most sun-screens protect through the majority of these.   And remember, it doesn’t matter if it is sunny or cloudy, there is still about 80% penetration of the UV rays.

There are physical sun-blocks (or what you will hear as mineral based sunscreens), and chemical sunscreens.  Just as you might expect, the physical sun-blocks reflect the light.  The prominent ones on the market have titanium dioxide and/or zinc oxide in them and work very well, as long as the correct amount is applied and reapplication is used.  These are my personal favorites, as I’d prefer to have a mineral on my skin then chemicals.  The chemical sunscreens have a multitude of different chemical they use and these work by absorbing photons from light.

Most of us don’t think about anything besides UV rays, but there are other things the sun puts out that are also damaging, such as infrared and just heating the skin.  Let me tell you a little about infrared solar-aging.  Infrared radiation makes up about 54% of the solar radiation and consists of three types, just like UV:  IR-A, IR-B, and IR-C.  IR-A causes the most damage to the dermis and subcutaneous tissue, while IR-B damages higher in the skin with 72% in the epidermis.  A small amount of damage occurs to the dermis and epidermis with IR-B as well, but IR-C effects the epidermis 100%.  Sun-screen does nothing at all to protect from infrared.  You must use clothing protection and always, always wear a wide-brimmed hat when outside (not a ball-cap as it doesn’t protect the sides of face, lower face, or neck and decollete area).  Find a pretty one!  In addition to UV rays and infrared, thermal aging occurs with skin temperatures greater than 40 degrees Celsius (104 degrees Fahrenheit).   All of these things together cause an increase in free radicals in the skin.  When free radicals attack, it leads to cell death and inflammation.  Wow!  Who knew the sun was so bad for us?  Well, now you do.

What about tanning beds?  Stay away from them entirely.  With tanning bed use, there is a 50% increased risk of malignant melanoma this is a killer.  To put things into perspective, the number of skin cancer cases due to tanning is higher than the number of lung cancer cases due to smoking.  In the US alone, over 400,000 cases of skin cancer can be attributed to indoor tanning and out of this number over 6,000 are melanoma cases.

I hear so many people say they hate being “white”, meaning not tan.  I say, “Embrace your skin’s natural color and have beautiful skin.”   Tan is synonymous with damaged skin.  Protect your skin and keep it healthy and youthful appearing.

I hope this convinces you to protect your skin from the sun’s harmful rays.

Shari J. Twigg, MD