Dear Dr. Toshi,

I heard that the skin renews itself. If that's the case, then why do we get scars when we get an injury or acne?

There are two big reasons for scarring. One reason is damage to the deeper layers of the skin and another reason is related to the healing process.

The upper layers of the skin that are renewed are called the epidermis, and they are constantly replacing themselves by shedding. The upper layers shed, but the deeper layers (called the dermis) don't. So, if you damage the deep layers of the dermis, they don't turn over. Unfortunately, as we get older, it takes longer for the upper layers to turn over, too. For example, people in their twenties shed and renew their skin in just 14 to 21 days, while it can take up to 60 days for people in their fifties! Anyway, if you damage the deep layers, they don't turn over, and the damage results in scar tissue.

Another reason for scar tissue is the healing process of the skin. Our skin contains a protein called collagen, which you've probably heard of. We're born with cells in our skin that make collagen. When you get injured, our warrior cells, called white blood cells, come to the site of the injury and start the process of wound healing. This process involves production of collagen, but unfortunately, the collagen that's used for wound healing is different from your normal skin collagen (which is fetal collagen). Interestingly, as you might have guessed from the name, fetuses (unborn babies) don't get scars! But for you and me the scar collagen comes to the wound quickly, and it remains there while skin cells are renewed, and that produces scars.

These are some tips that the American Academy of Dermatology gives people to help reduce scarring:

1. Clean your cut, scrape, or other skin injury with mild soap and water.
2. After cleaning it, apply a layer of petroleum jelly (like Vaseline) over it to keep it moist. Then use a bandage to cover the wound.
3. Clean the wound, reapply petroleum jelly, and change the bandage daily.
4. See your doctor or provider right away if it looks like you need stitches or if your injury is deep, very painful, or if it looks like it might be infected (redness, swelling, painful, warm, and/or pus is coming out of it).
5. After the wound heals, apply sunscreen to it. That will help the redness of the wound fade faster, and of course it also protects from skin cancer. According to the American Academy of Dermatology, skin wounds are more likely than healthy skin to become cancerous.

I hope this helps for you to have a safer summer with fewer scars!

Dr. Toshiko ("Toshi") Luckow, MD, is a Family Physician at the West River Health Services Hospital and Clinics.