How Skin Heals

Over the years I've been foolish fortunate enough to have invited medical students into my office for preceptorships. With my new blog persona, of course, what else to call them but The Hatchlings. I find myself thinking about them even after they've left, and when interesting things happen with patients they saw with me, I want to find a way to share it with them.

Dear Hatchling #3:

Remember that patient we did a home visit on back when you were in the office with me? The diabetic amputee with the wound on her (one remaining) leg that wouldn't heal? Well, the good news is that it finally healed. The bad news is that she spilled some hot gravy on her lap while cooking (since she has to do everything from a seated position) and sustained some nasty burns to her thighs a few weeks back.

The really good news is that they were fairly shallow second degree burns. This means that the epidermis was destroyed and sloughed off as blistering, leaving the underlying dermis exposed, painful and vulnerable to infection. All I did was keep the wounds clean and dressed them with an antibacterial/vaseline coated gauze while they healed, which they did beautifully after about two weeks. I went back to see her once or twice a week to make sure they weren't getting infected or anything (they didn't) and were healing ok (they were.)

By the last visit, the wounds had healed completely. If you ran your fingers over the skin, it was smooth; completely epithelialized, but its appearance demonstrated something really cool about the anatomy of the skin that I wished I could show you. Then I thought of a way I could: after asking the patient's permission, I whipped out my trusty cell phone and voila!

Going back to the anatomy of skin, recall that the epidermis doesn't sit flat on top of the dermis like a bedspread. Rather, the dermis has little fingerlike projections that poke up into the epidermis, kind of like a foam "eggcrate" mattress; pink in this picture:

The epidermis and top of the dermis were destroyed by the scald wound, but the three dimensional structure of the dermis meant that there were regularly arrayed indentations where little bits of the basal layer were preserved. Those little brown/black dots you see represent the migration of pigment cells from the dermal crypts moving up and spreading out into the newly regenerating epidermis. Eventually, the area's pigmentation will become uniform, as the "dots" appear to spread and coalesce. That's what "healing without scarring" means.

Hope second year is going well for you.

Best,
Dr. Dino

Edited to add Hatchling Index:

1. KK
2. JB
3. CW

(Defined as students in the office subsequent to the adoption of my blog persona)