Atrophic vs. Hypertrophic: A Visual Guide to Types of Acne Scars

Not all scars are the same—and misidentifying your scar type is one of the biggest reasons treatments fail to deliver expected improvement.

While different types of acne leave behind different textural signatures, the healing process generally follows two paths: some scars sit below the skin surface, while others rise above it. In some cases, the marks left behind aren’t permanent scars at all.

This guide breaks down the two major scar categories, explains common look-alikes, and shows how various types of acne evolve into permanent “legacy” scarring—so you can understand what you’re actually dealing with before considering treatment.

First: Are You Looking at a Scar — or Something Else?

Before classifying scars, it’s important to rule out one common confusion.

Post-Inflammatory Erythema (PIE)

Post-Inflammatory Erythema (PIE) appears as:

• Flat red or pink marks
  
• Most visible after acne heals
  
• Smooth skin texture when touched
  

PIE is not a scar. It represents vascular damage, not collagen loss.

Because PIE involves dilated or damaged blood vessels, it responds better to vascular-targeting lasers (such as VBeam) — not resurfacing or scar-release treatments used for pitted scars.

If the skin looks red but feels smooth, you’re likely dealing with PIE rather than true scarring.

Atrophic Scars: When the Skin Loses Structural Support

Atrophic scars are depressed scars that result from insufficient collagen production during the healing process. They sit below the surrounding skin surface.

The Atrophic Trinity

Most atrophic scars fall into what’s known as the Atrophic Trinity — the “Big Three”:

1. Ice Pick Scars

• Narrow opening
  
• Extend deep into the dermis
  
• Appear like tiny puncture marks
  

These are often the most challenging to treat due to their depth and narrow shape.

2. Boxcar Scars

• Wider with sharp, defined edges
  
• Flat bases
  
• Can be shallow or deep
  

They often respond well to resurfacing when not deeply tethered.

3. Rolling Scars

• Wavy or sloping appearance
  
• Skin looks uneven rather than sharply indented
  
• Often caused by fibrous bands pulling the skin downward
  

Rolling scars are commonly tethered, which affects treatment planning.

The “Pinch Test”: Is the Scar Tethered?

A simple self-assessment called the ‘Pinch Test’ can help identify scar depth.

How to do it:

• Gently pinch the skin around the scar
  
• Observe what happens to the indentation
  

What it tells you:

• If the scar lifts and smooths, it may be superficial
  
• If it stays indented, the scar is likely tethered
  

Tethered scars often require mechanical release (subcision) before resurfacing can be effective.

Hypertrophic vs. Keloids: Raised Scars Explained

Raised scars result from excess collagen production, not loss.

Hypertrophic Scars

• Raised and firm
  
• Stay within the original wound boundary
  
• May flatten gradually over time

Keloids

• Extend beyond the original wound edges
  
• Can continue growing
  
• Often itchy, tender, or firm

This distinction matters because hypertrophic vs. keloids behave very differently and require different management approaches.

Genetic Predisposition: Why Scar Types Differ Between People

Scar behaviour isn’t random.

Genetic predisposition plays a major role in how skin heals:

• Some individuals produce too little collagen, leading to pitted scars
  
• Others produce too much collagen, resulting in raised scars
  

Skin type, ethnicity, family history, and inflammatory response all influence which direction healing takes.

This is why identical acne severity can leave very different scarring patterns in different people.

Scar Evolution: From Active Acne to Legacy Scarring

Scars don’t appear overnight.

Scar Evolution follows a predictable path:

1. Active acne inflammation
   
2. Prolonged tissue damage
   
3. Incomplete or excessive collagen repair
   
4. Permanent textural change
   

The transition from active acne to “legacy” scarring happens quietly — and reminds us there is a critical window for early intervention.

Treating inflammation early reduces the risk of collagen damage that leads to permanent scars.

Why Correct Identification Comes First

Atrophic scars, hypertrophic scars, keloids, and PIE may coexist on the same face, but they are not treated the same way.

Correct identification helps determine:

• Whether resurfacing is appropriate
  
• If subcision is required
  
• Whether vascular lasers are more suitable
  
• When collagen stimulation helps — or worsens scarring
  

Understanding your scar type is not about labels. It’s about choosing approaches that work with your skin biology instead of against it.

Understanding the Big Picture

While this guide provides the tools for self-assessment, it is common to find that your skin displays a combination of these textures simultaneously. Navigating the various types of acne scars can feel overwhelming, but pinpointing whether your skin is losing collagen (atrophic) or producing too much (hypertrophic) is the essential first step. 

By accurately categorizing the types of acne scars present on your skin, you can have a much more productive conversation with a dermatologist and build a treatment roadmap that addresses your specific skin history with precision.

Conclusion

If scars are the result of how your skin healed in the past, then identifying them correctly is how you shape its response going forward.

Once you can tell what kind of scar you have, you’re no longer guessing — you’re planning.