Acne Scar Types: How Dermatologists Classify Them and Why It Matters

Dermatologists treat acne scars as several distinct injuries. A narrow pit on the forehead and a broad, wavy dip along the jaw need very different procedures, so knowing which type you have is the first step in any realistic plan.

How acne scars form

A scar can form when a deep breakout heals. Not every pimple leaves one behind. The American Academy of Dermatology (AAD) notes that deep breakouts such as cysts and nodules are the most likely to scar, and that picking or squeezing raises the risk. DermNet adds that scarring is more common in moderate to severe acne and that smoking can increase severity.

The shape of the final scar depends on collagen. According to the Cleveland Clinic, when healing skin produces too little tissue the result is an indented scar, and when it produces too much the result is a raised one. DermNet describes acne scars as usually permanent, although they may improve on their own or with treatment.

Depressed (atrophic) scars

Depressed scars are by far the most common group. A systematic review in Scars, Burns & Healing puts atrophic scars at roughly 80 to 90 percent of acne scars, and the same review splits them into three subtypes. The AAD notes that most people with depressed scars have more than one type.

Ice pick scars

Ice pick scars are narrow, usually under 2 mm across, and V-shaped. They are deeper than they are wide and can extend into the deep dermis or the fat beneath it. DermNet lists them as the most common atrophic type. The Cleveland Clinic notes they often appear on the forehead and upper cheeks and are among the hardest scars to treat, a point echoed in a 2022 review in Clinical, Cosmetic and Investigational Dermatology.

Boxcar scars

Boxcar scars are round or oval depressions with sharp vertical edges and a flat base. They are typically about 1 to 4 mm wide, wider than ice pick scars but narrower than rolling scars, according to the AAD and the published reviews. Some are shallow and some reach deeper into the dermis, and that depth matters for treatment. The Cleveland Clinic notes they are common on the lower cheeks and jaw.

Rolling scars

Rolling scars are wide, shallow dips with sloping edges that give the skin a wavy look. The 2022 review explains that they are caused by fibrous bands tethering the skin to deeper tissue, which pull the surface down. DermNet notes that rolling scars can smooth out when the skin is stretched. They tend to appear on the lower cheeks and jaw.

Raised scars

Raised scars form when the skin makes too much collagen while healing. The AAD notes they are more common in people with darker skin tones.

Hypertrophic scars

Hypertrophic scars are firm, raised scars that stay within the borders of the original lesion. The AAD says they usually appear on the jawline, chest or back, often one to two months after a breakout clears.

Keloids

Keloids grow beyond the original spot. The AAD describes thickening skin as the first sign, usually appearing 3 to 12 months after the acne clears. DermNet notes keloids are more frequent on the jawline, chest and upper back, can keep changing over time, and are more common in skin of color. They can also return after treatment, which is why the AAD says dermatologists often combine methods for them.

Papular scars

The AAD also describes papular scars: small raised bumps that are skin-colored or lighter than the surrounding skin, often on the nose, chin, jawline or back. They can be mistaken for active acne.

Marks that are not scars

A flat red, pink, brown or lighter spot that does not change the skin’s surface is usually discoloration, not a scar. The AAD makes this distinction clearly: scars alter the texture or contour of the skin, while discoloration is flat and usually fades over time. This matters because a mark that will fade on its own needs a different plan from a true change in texture.

Why scar type decides treatment

Each scar type sits at a different depth and has a different structure, so each responds to different tools. The published reviews describe a fairly consistent pattern:

• Ice pick scars are too deep for standard resurfacing. Techniques that reach the base of the individual scar, such as TCA CROSS (a concentrated acid applied precisely into each pit) or punch excision, are the options most often described.
• Boxcar scars depend on depth. The Scars, Burns & Healing review notes that shallow boxcar scars respond to resurfacing, while deep ones resist superficial treatment. The 2022 review describes punch elevation as best suited to boxcar scars.
• Rolling scars are held down from below, so they need treatment beneath the skin. Subcision, which releases the fibrous bands, is the main option, and fillers and microneedling are also used.
• Hypertrophic scars and keloids are managed differently again. DermNet lists steroid injections, silicone gel or sheeting, pulsed dye laser, cryotherapy and surgical revision, and notes these scars are prone to recurrence.

Because most people have a mix of types, combining approaches is common. The Cleveland Clinic notes that multiple procedures or combinations are typical, and that treatments for facial scars may not apply to the back or chest.

How dermatologists grade severity

Dermatologists also grade overall severity. The Cleveland Clinic describes a four-step scale running from flat red marks to severe scarring that is clearly visible and hard to conceal. The Scars, Burns & Healing review refers to the Goodman and Baron scale for the same purpose.

What to expect at an assessment

According to the Cleveland Clinic, diagnosis is made by visual examination and no special tests are needed. The AAD says a dermatologist will look at the types and locations of your scars and ask how they affect your daily life and what result you hope for. The AAD also advises sharing every acne treatment used in the past two years, since some scar procedures can cause side effects if started during or soon after certain acne medications.

Both DermNet and the AAD stress one point before any scar work begins: active acne should be brought under control first, so new inflammation does not create new scars.

Reducing the risk of new scars

The same sources agree on prevention. Treat acne early and keep treating it, especially if a close relative has acne scars. Avoid picking, popping or squeezing breakouts. The Cleveland Clinic adds that smoking increases scarring and that sun exposure can darken existing scars, so daily sunscreen is worth the effort. If breakouts are deep, painful or already leaving marks, a dermatologist is the right next step.