PIE vs PIH: Red vs Brown Acne Marks Explained

PIE vs PIH comes down to color and cause: PIE (post-inflammatory erythema) is a flat red, pink or purple mark left by small blood vessels after a breakout, while PIH (post-inflammatory hyperpigmentation) is a flat brown, tan or gray mark made of extra pigment. Both are acne marks, not acne scars, and both usually settle with time and gentle care.

Knowing which one you have matters, because what helps each one is a little different. Here's how to tell them apart, why red marks after acne can hang around, and when to see a dermatologist.

What is the difference between PIE and PIH?

The difference between PIE and PIH is what causes the color. PIE is redness from tiny blood vessels that widened or were damaged during a breakout. PIH is extra melanin that your pigment cells made in response to the inflammation. PIE looks pink, red or purplish. PIH looks tan, brown, gray or dark brown.

Both start with an inflamed pimple. As the skin heals:

• In PIE, small blood vessels near the surface dilate or get damaged, and the area stays red after the spot itself has gone. Dermatologists gave this redness its own name in 2013 so it could be told apart from brown marks [1].
• In PIH, pigment cells (melanocytes) switch into overdrive and leave extra melanin behind in the skin [2].

Neither one changes the texture of your skin. Run a clean fingertip over a PIE or PIH mark and it should feel flat and smooth, just like the skin around it.

A quick side-by-side:

• PIE: pink, red or purple; flat; comes from blood vessels; easiest to see on light to medium skin
• PIH: tan, brown, gray or blue-gray; flat; comes from pigment; more common and longer lasting on medium to deep skin

How do you tell PIE vs PIH?

The easiest way to tell PIE vs PIH is a simple press test. Gently press a clear drinking glass, or the flat side of a clear plastic ruler, against the mark. If the color turns pale or almost disappears while you press, it's PIE, because you're pushing blood out of the vessels. If the color stays the same, it's PIH.

A few more clues help:

1. Look at the color in daylight. Red, pink and purple point to PIE. Brown, tan and gray point to PIH.
2. Think about timing. Fresh marks from a recent breakout are often red first. As the redness settles, some marks, especially on medium to deep skin, leave brown pigment behind.
3. Notice what changes it. PIE often looks brighter after a hot shower, a workout or anything that flushes your face. PIH tends to look darker after time in the sun.

You can have both at once, such as a red center with a brown edge. That just means you want a routine that looks after both.

What about purple acne marks?

Purple marks are usually PIE on medium or deep skin, where redness can look purple or dark red rather than bright red. Pigment that sits deeper in the skin can also look gray-purple or blue-gray [2]. The press test helps here too: purple that turns pale under the glass is redness, and purple that stays is pigment.

Why won't red marks after acne go away?

Red marks after acne often take several months to settle because the small blood vessels underneath need time to calm down and repair. Anything that keeps the skin inflamed slows that down, including picking, harsh scrubs, stacked acids, hot water, sunburn and new breakouts in the same area. Sometimes a lasting red mark is actually an early scar.

These are the most common reasons red marks stick around:

• Picking or squeezing. It re-injures the skin and restarts the inflammation.
• Over-exfoliating. Grainy scrubs and several acid products in one routine leave skin raw, which keeps it red.
• Sun. UV exposure adds inflammation and makes both red and brown marks look more obvious.
• Ongoing breakouts. If new spots keep appearing in the same area, the redness never gets a break.
• Irritating products. Anything that stings, burns or leaves your skin tight is working against you.

Many red marks settle over several months, and some take longer. That's normal, and it rarely means your routine isn't working.

If a red mark is still there after about six months, or it feels raised, dented or itchy, show it to a dermatologist. It may be an early scar or something else, and there are in-office options for stubborn redness.

Are acne marks the same as acne scars?

No, acne marks and acne scars are different. Acne marks (PIE and PIH) are flat changes in color, and your skin's texture stays normal. Acne scars change the texture: they're dents or pits in the skin, or raised, firm bumps. Marks usually settle with time and good habits, while scars usually need in-office procedures from a dermatologist.

The quick check: close your eyes and run a clean fingertip over the area. If it feels smooth and level, it's a mark. If you feel a dip, an edge or a bump, it's likely a scar, or a mark sitting on top of one. You can also shine a phone flashlight across your skin from the side. Scars cast tiny shadows; flat marks don't.

This matters because the plan is different. Marks respond to time, sun protection and gentle, consistent care. Scars need a dermatologist, who can talk you through procedures such as microneedling, lasers or fillers. For more answers, browse our acne marks FAQ.

Can you get PIE on dark skin or PIH on light skin?

Yes, anyone can get either kind of acne mark. PIE is easier to spot on lighter skin, where red stands out, while PIH is more common and longer lasting on medium to deep skin [2]. PIE still happens on dark skin, often looking purple or deep red, and PIH happens on light skin, where it looks tan or light brown.

Here's how it tends to look across skin tones:

• Fair and light skin: Red and pink marks (PIE) are the most common after a breakout. Light brown PIH can still show up, especially after picking or time in the sun.
• Olive, medium and tan skin: Both are common, often together. A mark may start red and leave a brown shadow as the redness settles.
• Brown and deep skin: PIH is the mark most people notice, and it can last for months or longer. PIE is still there, but it may look purple, dark red or simply darker than the skin around it, which makes it easy to confuse with PIH.

A review of acne in darker skin noted that even breakouts that look mild on the surface can show strong inflammation underneath [3], which helps explain why marks are so common on melanin-rich skin. Whatever your skin tone, the basics are the same: keep inflammation low, wear sunscreen daily and give it time. For the habits that make marks linger, read 3 everyday habits making your dark marks worse.

What helps red and brown acne marks look less noticeable?

The most helpful steps for both red and brown acne marks are the same: stop new breakouts, keep your hands off, wear sunscreen every day and use a gentle routine that never stings. On top of that, brown marks respond well to brightening ingredients like vitamin C and niacinamide, used daily for 8 to 12 weeks.

For both PIE and PIH

1. Calm new breakouts. Fewer new spots means fewer new marks. Our guide to preventing acne breakouts covers the daily habits that help.
2. Wear broad-spectrum SPF 30 or higher every morning. Sun keeps redness going and darkens pigment. On skin types IV to VI, visible light caused darker, longer-lasting pigment than long-wave UVA in one study [4], so a tinted mineral sunscreen with iron oxides is worth considering.
3. Hands off. Don't pick, squeeze or scrub at marks.
4. Moisturize morning and night. A well-supported barrier is calmer and less reactive.
5. Choose gentle over strong. Stick to one exfoliating step at most, and pause it if your skin stings.

Extra care for red marks (PIE)

Red marks are about calming the skin, not brightening it. Skip hot water and steam on your face, keep your actives simple, and look for soothing, barrier-supporting ingredients. Niacinamide is a gentle option that many people with redness-prone skin use every day. Be patient: time does most of the work here.

Extra care for brown marks (PIH)

Brown marks are where brightening ingredients earn their place. Vitamin C slows tyrosinase, the enzyme that starts pigment production [5], and niacinamide reduced the transfer of pigment to surrounding skin cells in research [6]. Read more in how vitamin C works on dark spots.

Our Superactive Serum pairs 15% vitamin C with niacinamide for a brighter, more even-looking tone, and our Advanced Brightening Moisturizer combines three ceramides and hyaluronic acid with vitamin C to support your barrier. Used daily with sunscreen, they help marks look less noticeable over time. Most people see a more even-looking tone after 8 to 12 weeks, and results vary.

Take a photo in the same light every four weeks. Marks change slowly, and photos show progress the mirror misses.

When should you see a dermatologist about acne marks?

See a dermatologist if your acne marks haven't changed after three to six months of consistent care and daily sunscreen, if you keep getting new breakouts that leave marks, or if marks are raised, dented, itchy or painful. A dermatologist can confirm what you're seeing and discuss prescription options and in-office procedures.

Also book an appointment if:

• Your acne is deep, painful or cystic
• You tend to form raised or keloid scars
• A spot changes in size, shape or color, bleeds, itches or grows
• Marks are affecting your mood or confidence

For red marks that won't settle, dermatologists may suggest lasers or light-based procedures aimed at redness [1]. For brown marks, they can choose prescription options and procedures with your skin tone in mind, since some approaches can irritate deeper skin and leave more pigment behind.

References

1. Bae-Harboe YS, Graber EM. Easy as PIE (postinflammatory erythema). Journal of Clinical and Aesthetic Dermatology (2013).
2. Davis EC, Callender VD. Postinflammatory hyperpigmentation: a review of the epidemiology, clinical features, and treatment options in skin of color. Journal of Clinical and Aesthetic Dermatology (2010).
3. Davis EC, Callender VD. A review of acne in ethnic skin: pathogenesis, clinical manifestations, and management strategies. Journal of Clinical and Aesthetic Dermatology (2010).
4. Mahmoud BH, Ruvolo E, Hexsel CL, et al. Impact of long-wavelength UVA and visible light on melanocompetent skin. Journal of Investigative Dermatology (2010).
5. Al-Niaimi F, Chiang NYZ. Topical vitamin C and the skin: mechanisms of action and clinical applications. Journal of Clinical and Aesthetic Dermatology (2017).
6. Hakozaki T, Minwalla L, Zhuang J, et al. The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer. British Journal of Dermatology (2002).

This article is for general information and isn't medical advice. If you have a skin condition or concern, talk to a doctor or dermatologist.