Many people with dark skin come to the dermatologist complaining of “scars” referring to dark spots they may have on their skin. These dark marks may be the result of skin trauma from things such as acne, a rash, a burn, a scratch or a cut. The patient may have tried over-the-counter scar treatments that didn’t work. Well, it’s no surprise that the scar treatment didn’t work because not all marks on the skin that we refer to as “scars” are actually scars.
Dark marks, blemishes, or what dermatologists refer to as post-inflammatory hyperpigmentation are different from scars. These dark marks are the result of increased pigment production by melanocytes, the cells in the skin responsible for brown skin color and tanning. Melanocytes live at the base of the superficial layer of the skin called the epidermis. The pigment melanocytes produce is called melanin. Melanin is darkly colored and thus makes skin darker. Melanocytes in people with darker skin are more active producing more melanin at baseline and in response to injury. People with light skin also have melanocytes but they are not as productive.
True scars, on the other hand, result from damage to the dermis, the deeper layer of the skin. The dermis is the structural layer of the skin comprised of proteins called collagen and elastin which gives skin strength and elasticity. A scar results in a change in skin texture. Just as with hyperpigmentation, scars, too, are caused by skin trauma such as acne, deep cuts, burns, scratches or rashes. Interestingly, some scars can also become hyperpigmented (darker) or even hypopigmented (lighter)
If hyperpigmentation, and scars are both caused by skin trauma, but they are not the same things, then how are they different? Think of it like this. If one had a tee shirt that one spilled grape juice on, there would be a stain. That is more like post-inflammatory hyperpigmentation. If one tore the tee shirt then sewed up the hole, the texture would be different. That would be more like a scar. Also, unless it is really deep in the skin, post inflammatory hyperpigmentation is usually temporary. It tends to fade over months, even without treatment, so long as the underlying cause has been addressed. Scars are permanent although they tend to improve over time.