How Does the Sun Damage the Skin?

By Dr. Surjit Rai

We tend to assume that damaged skin just comes with aging. Almost all old people have wrinkles, discoloration, blemishes and/or leathery skin. But over-exposure, or long chronic exposure, to the sun’s ultraviolet rays is what mostly causes these defects.

A young person on the beach or out sailing, with smooth suntanned skin, does not usually realize that an attractive suntan is just Stage One of Wrinkles/Brown Spots/Leathery Texture. Then there is skin cancer, which begins unobtrusively but can metastasize quickly and become hard to treat. A tanning booth causes as much harm as the sun.

Ultraviolet (UV) Light

UV light travels at a certain range of wavelengths and is divided into three categories:

• UVA, at 100 to 290 nm – which penetrates deeply into the skin’s middle layer (dermis), does not vary in its intensity during the daylight hours, and cannot be filtered out by glass
• UVB, at 290 to 320 nm – which only penetrates the top skin layer (epidermis), causes sunburn, is most intense during the middle daylight hours and summer months, and can be screened out by glass
• UVC, at 320 to 400 nm – which does not affect our skin because it is mostly absorbed by the ozone layer

How Sun Damage Occurs

The mechanisms of how it occurs are not yet fully understood. But it is agreed that some processes seem likely:

• Collagen destruction. The skin’s dermis, middle layer, has a supportive matrix of collagen and elastin fibers (two types of connective tissue common in the body). UV rays speed the breakdown of collagen and cause accumulation of elastin in the skin. Elastin produces enzymes which normally help to rebuild collagen, but in sun-damaged skin there are extra enzymes which break down some of the collagen and disorganize others, causing wrinkles to form
• Free radicals. Oxygen molecules normally have two electrons but UV rays create some with only one. These are free radicals and they need a second electron, so they scavenge one from some other molecule. Then that molecule has only one and must scavenge. This process activates the same enzymes produced by elastin and helps destroy collagen. It also changes the RNA and DNA (genetic material) in skin cells, causing cancer.

There are other processes that are less well-understood. One involves chemicals that suppress the immune system and certain enzymes which would otherwise repair damaged DNA. Another blocks an immune system mechanism called apoptosis that would normally destroy damaged cells, preventing them from becoming cancerous. Instead, they survive, continue to divide and potentially do become cancerous.

Treatments We Offer

Sun-damaged skin can be treated by somehow stimulating it to create new and firmer collagen. This can be done with dermal fillers, chemical peels and laser resurfacing. These treatments cause the skin to regenerate itself with tighter and more youthful-looking structure. You can also temporarily smooth the skin surface with BOTOX® injections.

Please contact our office in Dallas, Texas if you would like to have a free consultation with cosmetic surgeon Dr. Rai.