Skincare Addiction often stresses the importance of daily sun protection, via proper sunscreen application, but sometimes the message of why you should care about sun protection is lost. Photoprotection means more more than just having good-looking skin; it’s also about having healthy skin.
This article will introduce the different types of the sun’s rays, give an overview of the types of damage these rays can cause, and provide a quick reference guide for sun protection.
What is sun damage?
Sun damage refers to skin exposure to ultraviolet radiation (UVR). UVR is present during all daylight hours – yes, even if it’s cloudy or overcast! There are several classifications of these UV rays:
UVA (315-400 nm wavelength)
Long-wavelength rays that penetrate down into the dermis (the deeper layers of skin below the epidermis). UVA rays are commonly referred to as the “aging” rays because of the type of damage they do to the skin. They are largely responsible for DNA damage and pigmentation darkening following sun exposure (like tans and freckles).
UVB (290-315 nm wavelength)
Short-wavelength rays that do not penetrate to the dermis. UVB rays are often called the “burning” rays because they cause erythema (redness) and sunburns soon after exposure.
UVC (270-290 nm wavelength)
Very short-wavelength rays that are completely filtered by the ozone and stratosphere. UVC radiation is not a concern in your day-to-day life.
Effects of Sun Damage
When UVA and UVB radiation comes into contact with unprotected skin, several types of damage can occur from a slight burn on your cheeks to permanent wrinkles and DNA damage (see below for more on DNA damage). The following is not an exhaustive
Immediate Effects (0-2 hours after exposure)
Sunburn and redness. Although erythema from UVR happens quickly it can also persist for up to 3 days after high-dose exposure. Severe erythema can result in blisters and scarring.
Immediate Pigment Darkening (IPD)
Pigmentation that develops within minutes and fades within a couple of hours. This is the reaction of melanin shifting around in your skin cells when exposed to UVA radiation. Melanin is what gives our skin it’s color. Darker skin types have more melanin.
Delayed Effects (2 hours – several weeks after exposure)
Persistent Pigment Darkening (PPD)
More shifting around of current melanin in the skin; follows IPD and can last for a day. No new melanin is produced during IPD or PPD. Reorganizing the concentration of melanin is one of the ways your skin tries to protect itself. Positioning melanin in a concentrated manner is somewhat protective from future UVR exposure.
This is a fancy term for “tanning.” It occurs 3-5 days after sun exposure and can persist for several weeks after exposure. If you’ve ever tanned (in a booth or by the pool) this is why you don’t see the full effects of the damage until a few days later. Duration of delayed tanning is largely due to skin type. Darker skin types show longer reactions of delayed tanning, whereas fairer skin types have shorter delayed tanning responses.
Chronic Effects (long-lasting)
Mostly caused by UVA that penetrates the dermis. Signs of photoaging include wrinkles, sun spots, decreased collagen production (loss of elasticity), and large open comedones (blackheads).
UVR alters the normal functioning of the immune system. Cells that would normally fight off infection and repair DNA damage, no longer function normally after UVR exposure.
In response to sunburn, the skin exhibits proinflammatory responses (e.g., blisters; erythema). These immunosuppressive responses are why some skin disorders will improve after a moderate dose of UVR (like seborrheic dermatitis)– inflammation occurs in reaction to the skin disorder and UVR dampens that response, thus reducing inflammation. Though, there are certainly trade-offs to UV therapy for skin disorders.
DNA mutations induced by UVA exposure. Immunosuppression responses in the skin lower the chance that your immune system will recognize the growth of damaged cells. This is one way skin cancer is thought to proliferate.
So what can you do to prevent photodamage?
- Make sure to check out our guide on choosing a sunscreen. Yes, even in the winter and even on cloudy/rainy days! Cloud cover prevents a lot of UVB rays from reaching the Earth’s surface, but the majority of UVA rays still get through.
- Wear UPF clothing. Skincare Addiction partnered with Canopy Sun Protection to make our tunic, and we will be announcing a new piece for the Spring 2015 collection!
- Seek shade when outside. Trees and walking on the shaded side of the street keep you cool and protected.
- Apply UV protective film to vehicle windows. Glass blocks the majority of UVB rays, but does not attenuate many UVA rays. The windshield and (most) rear windows provide UVA protection, but side windows are almost never coated. Ask your mechanic or dealer about protective films if you’re unsure. These films can block up to 99% of UVR and they keep the interior cooler.
- Wear hats and sunglasses. Wider brims made of solid material offer more protection. Additionally, it can be difficult to apply sunscreen close to the eye area. Sunglasses protect your ocular tissue (the eyeball) and the surrounding skin.