PIH, PIE or Acne Scar? How to Tell What Your Breakout Left Behind

If you’ve ever finally cleared a breakout only to stare at the mirror a week later thinking, “Okay, but what is that?”, you’re not alone. Clients often call every leftover mark a “scar,” but a flat brown spot, a lingering pink spot and a true dent in the skin are three different things. They happen for different reasons and respond to different care. Let’s sort them out.

What Breakouts Can Leave Behind

When a blemish heals, it can leave one of three main souvenirs, and sometimes more than one at once:

Post-inflammatory hyperpigmentation (PIH). A flat spot that’s darker than your surrounding skin, usually tan to dark brown. It’s extra pigment, not damaged tissue.
Post-inflammatory erythema (PIE). A flat spot that’s pink, red or purplish. It’s about blood vessels, not pigment.
Acne scars. A true change in the skin’s surface. Most acne scars are atrophic (sunken), and a smaller number are raised (hypertrophic or keloid).

The key word is flat. PIH and PIE are color changes; a scar is a texture change.

Why Each One Happens

PIH is your pigment cells overreacting. Inflammation releases signaling molecules that tell melanocytes to make and hand off more melanin. Pigment that stays in the upper layer (epidermis) tends to look brown; pigment that drops into the deeper layer (dermis) looks more gray or blue-gray and lingers longer.
PIE is leftover vascular change. Inflammation widens the tiny capillaries near the surface, and they can stay dilated for a while after the blemish is gone.
Scars are a collagen problem. Deep, long-lasting inflammation damages the dermis. When healing doesn’t rebuild enough collagen, you get a depression; when it builds too much, you get a raised scar.

Here’s something I love about skin: the same breakout can leave a totally different mark on two different people. Deeper skin tones have more active melanocytes, so they’re more likely to show PIH. Lighter skin tones show redness more easily, so PIE tends to be more visible.

What the Research Shows

PIH is very common in skin of color. A review by Davis and Callender in the Journal of Clinical and Aesthetic Dermatology (2010) cites a 2002 study in which acne-related PIH developed in roughly 65% of African American, 53% of Hispanic and 47% of Asian patients studied. The same review notes epidermal PIH can take months to years to fade on its own, and deeper (dermal) PIH can be very persistent.
Most acne scars are sunken. A 2017 review in the same journal (Connolly and colleagues) reports that atrophic scars make up the large majority of acne scars, divided into ice pick (narrow and deep), boxcar (wider with sharp edges) and rolling (wide, soft, wavy) types. The authors link scarring to how severe and long-lasting the inflammation was.
PIE research is thinner. Vascular lasers, light devices and some prescription topicals have been studied, mostly in small or short trials. A 2025 split-face report in Clinical, Cosmetic and Investigational Dermatology notes there’s still no standard treatment. PIE often fades on its own over months, and in some people it lingers longer.

How to Tell Them Apart

These are clues, not a diagnosis, but they’re the same simple observations I use when I’m looking at skin in good light:

Check the color. Brown, tan or gray points toward PIH. Pink, red or purple points toward PIE.
Try the press test. Gently press a clear glass or your fingertip on the spot. If the red fades briefly and comes back, that’s blood flow, which suggests PIE. Pigment doesn’t blanch.
Use side lighting. Hold a light (or stand by a window) so it hits your face from the side. Flat marks don’t cast shadows; scars do.
Stretch it. Gently stretch the skin. Rolling scars often soften when stretched; ice pick scars usually don’t.

Who Should Take Extra Care

Anyone with active, inflamed acne. Calming breakouts comes first; treating marks while new ones keep forming is an uphill climb. Moderate to severe or cystic acne belongs with a dermatologist.
Deeper skin tones. Aggressive peels, scrubs and some lasers can trigger new PIH, so a slow, conservative plan matters.
Anyone on prescription acne medication (especially isotretinoin, now or recently). Many professional treatments need to wait; your provider sets that timeline.
Any spot that’s changing, bleeding or doesn’t look like a healed blemish. Have a physician check it.

How to Care for Each One

Hands off. Picking and squeezing add inflammation, which deepens PIH and raises the odds of scarring.
Daily sunscreen, every season. UV keeps PIH darker for longer. Here in Utah, our altitude means more intense UV, and fall and winter snow reflect it back up at you. For pigment-prone skin, a tinted sunscreen with iron oxides adds protection from visible light, which a 2026 Journal of Drugs in Dermatology review supports, though labels rarely say how much iron oxide is inside.
For PIH: patient, gentle brightening helps, such as azelaic acid, niacinamide, vitamin C, retinoids or a gentle exfoliant like mandelic acid. Prescription options are a conversation for your physician.
For PIE: focus on calming the skin and protecting your barrier. Skip harsh scrubs and hot water. If it’s stubborn, vascular lasers are a physician-level or med spa option. Azelaic or mandelic acid can also help remove superficial redness from acne marks.
For scars: topicals can soften the look of very mild texture, but true scars usually need in-office procedures. The American Academy of Dermatology lists options like chemical peels, microneedling, lasers, fillers and scar surgery, often combined, and recommends getting acne under control first.
Patch test and introduce one new product at a time. Irritation is its own trigger for PIH.

Fall is a great time to start working on marks, since lower UV makes treatment more forgiving. (For more on gentle exfoliation, see my lesson on mandelic acid.)

Common Myths

“Every dark spot is a scar.” Flat brown and red marks aren’t scars. They usually fade with time, sun protection and the right care.
“Scrubbing harder will fade it faster.” Friction is inflammation, and inflammation makes PIH worse.
“Vitamin C serum will fix my acne scars.” Brightening ingredients can help with color. They can’t refill a depression.
“Darker skin doesn’t need sunscreen.” Darker skin is often the most PIH-prone, and sun keeps those spots around.

The Takeaway

Before you treat a mark, name it. Brown and flat is usually PIH, pink and flat is usually PIE, and a dent or bump is a scar. Color changes often respond to patience, gentle actives and sunscreen; texture changes usually need professional help. Whatever you’re seeing, calming active acne and keeping your hands off are the two best ways to prevent the next one.

Sources

Further reading: Taylor and Kelly’s Dermatology for Skin of Color, edited by A. Paul Kelly and Susan C. Taylor; Acne Scars: Classification and Treatment, edited by Antonella Tosti, Maria Pia De Padova and Kenneth Beer; Skincare Decoded by Victoria Fu and Gloria Lu.

This lesson is for general education and is not a substitute for a personalized consultation with a licensed skin professional or a medical provider.

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