Types of Acne Scars: Ice Pick, Boxcar, Rolling and Raised

There are four main types of acne scars. Three are indented, or atrophic: ice pick scars are narrow and deep, boxcar scars are round or oval dips with sharp edges, and rolling scars are wide, shallow and wavy. The fourth group is raised: hypertrophic scars, keloids and papular scars. Flat red or brown marks left after a pimple are usually not scars and tend to fade.

Below is how to recognize each type in a mirror, how atrophic and hypertrophic scars differ, what dermatologists use for each one, and how to tell a true scar from a mark that only needs time.

What are the main types of acne scars?

Acne scars fall into two families, depending on what happens to collagen as a breakout heals. The American Academy of Dermatology (AAD) explains that if your skin makes too little collagen to fill the area, a depressed scar appears, and if it makes too much, you get a raised scar. Most people with scarring have the depressed kind, and many have more than one subtype at once.

The three-part split of depressed scars into ice pick, boxcar and rolling comes from a 2001 classification in the Journal of the American Academy of Dermatology, which its authors proposed so doctors could match each scar type to a treatment. A later review in Dermatology Research and Practice puts the proportions at roughly 60% to 70% ice pick, 20% to 30% boxcar and 15% to 25% rolling, and notes that atrophic scars outnumber hypertrophic scars and keloids about 3 to 1.

The sizes come from the Dermatology Research and Practice review; the treatment columns draw on the AAD's treatment guide and DermNet.

What do ice pick scars look like?

Ice pick scars are tiny, deep holes that look as if the skin was pricked with a sharp tool. The AAD calls this the most common type of acne scar: it looks small but goes deep into the skin. DermNet describes them as narrow, deeper than they are wide, and V-shaped, with a sharp edge running down into the deep dermis or the fat below it.

Because the opening is so narrow, ice pick scars can pass for enlarged pores at a quick glance. Side light helps: a deep scar tends to show as a dark pinpoint, and unlike a rolling scar it doesn't flatten when you stretch the skin.

How are boxcar scars different from ice pick scars?

Boxcar scars are wider, with a flat floor and steep walls, so they look like a small crater instead of a pinprick. The AAD notes they are wider than ice pick scars but not as wide as rolling scars. The Dermatology Research and Practice review compares them to chickenpox scars and splits them into shallow (0.1 to 0.5 mm deep) and deep (0.5 mm or more) types. Depth is one of the things a dermatologist checks before picking a treatment.

What are rolling acne scars?

Rolling scars are broad, gentle depressions that give the skin a wavy, uneven surface, especially in light coming from the side. They form when bands of fibrous tissue tether the dermis to the layer beneath it and pull the surface down. DermNet points out a simple tell: rolling scars have sloping edges that can be smoothed out if the skin is stretched. If you gently spread the skin between two fingers and the dip mostly disappears, you're likely looking at a rolling scar. An ice pick or deep boxcar scar stays visible.

What are raised acne scars?

Raised scars form when the skin lays down too much collagen while healing. The AAD lists three kinds and notes that raised acne scars are more common in people who have darker skin tones:

• Hypertrophic scars feel firm, usually appear on the jawline, chest or back, and tend to show up 1 to 2 months after a breakout clears.
• Keloids grow larger than the breakout that caused them. The first sign is thickening skin, usually 3 to 12 months after the acne clears, and the AAD says a pressure garment worn at that stage can prevent a keloid or reduce its size.
• Papular scars are skin-colored or lighter bumps, often on the nose, chin, jawline or back, and the AAD notes they can be mistaken for acne.

Atrophic vs hypertrophic scars: what's the difference?

Atrophic scars sit below the surrounding skin because collagen was lost; hypertrophic scars sit above it because collagen was overproduced. DermNet explains that most acne scars come from an inflammatory response that destroys collagen fibers in the dermis, while a net gain of abnormal collagen produces hypertrophic or keloid scars. It also draws the line between the two raised types: a hypertrophic scar stays the size of the original lesion, while a keloid grows beyond it.

The difference drives treatment. For indented scars, the goal is to rebuild or lift tissue. For raised scars, the AAD notes the opposite problem, too much collagen, so they need different treatment.

Is it a scar or just a mark?

If the spot is flat and only a different color from your skin, it's usually a mark, not a scar. The AAD is direct about this: flat spots after acne are usually not scars. In lighter skin they tend to be red or pink, and in medium or darker skin they're more often brown or bluish gray. These marks usually fade over time.

A quick way to sort them:

1. Run a fingertip over the spot. A change in texture (a dip or a bump) suggests a scar; a smooth surface suggests a mark.
2. Hold a light or your phone flashlight to the side of your face. Scars cast a shadow, flat marks don't.
3. Look at the color. Pink, red or purple flat spots are often post-inflammatory erythema, covered in our guide to red marks after acne. Brown or gray flat spots are usually post-inflammatory hyperpigmentation; see how to fade dark spots.

Many faces have both at once. DermNet notes that color changes such as redness and darker or lighter patches may appear before or alongside scar formation, and that they often improve with time, although that can take months or longer. If you're unsure whether your spots will settle, our article on whether acne scars go away covers what to expect over a year.

Which treatments work for each type of acne scar?

Each scar type responds to different procedures, which is why the AAD stresses that ice pick scars require different treatment than rolling scars. Most people need a combination. Dermatologists also treat active acne first, because new breakouts can create new scars, and the AAD asks patients to mention every acne medicine used in the last two years, since some scar treatments cause side effects when started during or soon after certain acne treatments.

Ice pick scars: TCA CROSS and punch techniques

TCA CROSS (chemical reconstruction of skin scars) applies a very strong trichloroacetic acid, 65% to 100%, only inside each scar so the floor heals and rises. In the study that introduced the method, 65 patients with Fitzpatrick skin types IV and V were treated; 82% of the 65% TCA group and 94% of the 100% TCA group had a good clinical response, with no significant complications reported. Narrow, deep scars can also be cut out with a small round punch and closed, one of the core techniques in the original classification paper's treatment algorithm.

Boxcar scars: lasers, punch elevation and fillers

The Dermatology Research and Practice review states that all patients with boxcar or rolling scars are candidates for laser treatment, using ablative lasers such as CO2 and erbium or gentler nonablative devices. Punch techniques, including punch elevation, are also part of the 2001 treatment algorithm. Fillers add volume beneath a dip; the AAD notes that most fillers give temporary results lasting 3 months to 2 years and need touch-ups.

Rolling scars: subcision and microneedling

Subcision targets the tethering bands behind rolling scars. A needle is slipped through a tiny puncture and moved under the scar to make small cuts beneath it, which releases and lifts the depression, and new connective tissue that forms during healing helps hold it up. Microneedling, or collagen induction therapy, punctures the skin with tiny needles to trigger new collagen. The AAD notes that microneedling is safe for all skin tones and is often paired with radiofrequency, a chemical peel or platelet-rich plasma.

Raised scars: injections, lasers and silicone

For hypertrophic scars, the AAD lists lasers, corticosteroid injections or prescription medicine applied to the scar, and lasers for papular scars. DermNet adds silicone gel or sheeting worn 24 hours a day for some months, and warns that hypertrophic and keloid scars are prone to come back even after treatment that seemed successful.

What about creams?

Topicals help only at the mild end. The AAD says that for mild acne scarring, a retinoid or salicylic acid can make scarring less noticeable. They won't lift a deep ice pick or boxcar scar.

Whatever the plan, expect a series of visits. The AAD notes that a mild chemical peel may take 3 to 5 treatments given every 2 to 4 weeks, that medical insurance does not cover acne scar treatment, and that scar treatment is rarely one and done, often needing three or more sessions. After treatment, it advises daily broad-spectrum, water-resistant SPF 30 or higher and limiting time in the sun for 6 to 8 weeks.

Does skin tone change which treatment is safest?

Yes, because deeper skin tones are more likely to develop dark marks after procedures. Darker skin is also more prone to raised scars, per the AAD. The Dermatology Research and Practice review cautions that medium-depth TCA peels are not indicated for dark skin because of the high risk of hyperpigmentation, while the focal TCA CROSS study above was run in Fitzpatrick IV and V skin without significant complications. The AAD describes both microneedling and radiofrequency microneedling as safe for all skin tones. Bring this up at your consultation, and see our skincare routine for dark skin for preventing marks day to day.

How can a selfie scan help you keep track of acne scars?

Texture changes slowly, and it's hard to judge a treatment series from memory. A consistent photo record helps: same window, same time of day, same angle, once a month. An app like Pori takes a selfie and returns an overall skin score with a Pores & Texture rating and a Pigmentation & Tone rating, and its before/after comparison and progress charts let you line up months side by side. That makes it easier to see whether flat marks are fading while indented scars stay put.

A scan describes how your skin looks in a photo. It is not a diagnosis and can't classify your scars or tell you which procedure to choose; that is a job for a board-certified dermatologist.

When should you see a dermatologist about acne scars?

See one if your acne is deep or painful, if new scars keep forming, or if a spot starts to thicken months after a breakout. The AAD notes you're more likely to scar if you get deep breakouts like cysts or nodules, or pick and scratch at them, so getting active acne under control is the best scar prevention there is. If that's where you are, start with our guide to treating cystic acne. For existing scars, a consultation is the place to match each scar type on your face to a plan that fits your skin tone, budget and downtime.