Quick Answer
PIE and PIH are different post-acne marks. PIE is a pink or red flat mark from damaged blood vessels, while PIH is a brown mark from excess melanin. PIH is more common in medium to deep Asian tones. Press gently to tell them apart, treat both with niacinamide and vitamin C, and wear daily sunscreen.
Skincare note: This article is for educational purposes only and is not medical advice. Always patch test new products and consult a dermatologist for any skin concern that affects your health or comfort.
One of the most frustrating parts of dealing with acne is that the breakout is only half the battle. Long after a pimple has healed, it can leave behind a mark that lingers for months. These marks are not scars in the textured sense, and the good news is that most of them fade with time and the right care. The first step is working out which kind of mark you actually have, because the two main types respond to different ingredients.
The Two Types of Post Acne Marks
Flat marks left after a breakout fall into two broad categories. Getting the name right matters because treating a red mark as though it were brown, or the other way around, wastes months of effort.
PIE stands for post inflammatory erythema. These are the pink, red, or sometimes purple marks left behind after a pimple. They are caused by damage to or dilation of the tiny blood vessels in the skin during inflammation. PIE tends to be more visible in lighter skin tones, but it affects all skin types. Clinical research on post inflammatory erythema is available from the National Institutes of Health (PMC).
PIH stands for post inflammatory hyperpigmentation. These are the tan, brown, or grey marks that appear after a breakout. They are caused by excess melanin, the pigment that gives skin its colour, produced in response to inflammation. PIH is especially common in medium to deep skin tones, which makes it a very frequent concern for Asian skin. A detailed overview of post inflammatory hyperpigmentation is available from the National Institutes of Health (NCBI).
Press gently on the mark with a clean finger for a second, then release. If the mark briefly fades or lightens before the colour returns, it is more likely PIE, because you are temporarily pushing blood out of the vessels. If the colour stays put when you press, it is more likely PIH, because melanin does not move. Many people have both at once.
Why Asian Skin Is More Prone to PIH
Asian skin spanning Fitzpatrick types III through VI has more reactive melanocytes, the cells that produce pigment. When the skin is inflamed by a breakout, picking, or even harsh products, these cells switch into overdrive and deposit extra melanin in the area. The result is the brown mark of PIH that can outlast the original pimple by many months.
This is also why being gentle matters so much for Asian skin. Any source of inflammation, including aggressive scrubbing, over exfoliating, or squeezing a spot, can trigger fresh PIH. The most effective long term strategy is to keep inflammation low in the first place, which prevents new marks while the old ones fade.
Not Sure What Is Causing Your Breakouts
Use the Acne Type Identifier to understand what kind of acne you are dealing with before you treat the marks it leaves behind.
Open Acne Type IdentifierWhat Causes Each One
Both PIE and PIH are the skin's response to inflammation, but the mechanism differs. PIE is a vascular response. The inflammation from a breakout damages or widens the small blood vessels near the surface, and the visible redness is essentially those vessels showing through while they heal. Anything that increases inflammation, such as picking at a spot, can deepen and prolong PIE.
PIH is a pigment response. The same inflammation signals melanocytes to produce more melanin, which then sits in the upper layers of the skin as a brown or grey mark. Sun exposure makes PIH dramatically worse, because UV light further stimulates melanin production in the already affected area. This is the single most important thing to understand about PIH: unprotected sun exposure can darken existing marks and slow their fading by months.
Ingredients That Help
Some ingredients are specific to one type, while several help both. Here is how to match them.
For PIE (pink and red marks)
- Azelaic acid reduces redness and inflammation and is gentle enough for sensitive skin.
- Niacinamide calms inflammation and supports the skin barrier, helping vessels settle.
- Centella asiatica soothes and supports healing, making it a favourite for calming redness.
- Gentle vitamin C supports the repair of blood vessels and overall skin recovery.
For PIH (brown marks)
- Vitamin C brightens and helps interrupt excess melanin production.
- Niacinamide reduces the transfer of pigment to skin cells, fading brown marks over time.
- Azelaic acid helps both inflammation and pigment, which makes it ideal for mixed marks.
- Tranexamic acid and alpha arbutin are gentle brighteners that target pigmentation.
- Retinol speeds cell turnover to clear pigment, used carefully to avoid irritation.
Sunscreen. Daily broad spectrum SPF 50 PA++++ protects healing blood vessels and prevents UV from darkening pigment. Without it, both PIE and PIH fade far more slowly, and PIH can get worse. If you do only one thing for post acne marks, make it sunscreen every single morning.
A Realistic Treatment Timeline
Patience is essential, because neither type of mark clears quickly. PIE often takes 3 to 6 months to fade, and sometimes longer, because blood vessels heal slowly. PIH typically takes 3 to 12 months, depending on how deep the pigment sits, your skin tone, and how consistent you are with sun protection. Deeper marks and darker skin tones generally take longer.
The way to speed things up is not to use stronger products, which often backfire by causing more inflammation. It is to stay consistent with gentle, effective ingredients, protect the skin from the sun every day, and above all avoid creating new marks. Resist the urge to pick or squeeze, since a single squeezed spot can leave a mark that takes half a year to fade.
Build a Gentle Routine for Marks
Use the Routine Builder to create a calm, consistent routine that fades marks without triggering new ones.
Open Routine BuilderWhat Not to Do
A few common mistakes make post acne marks worse rather than better. Over exfoliating in the hope of scrubbing marks away causes inflammation that deepens both PIE and PIH. Skipping sunscreen undoes all your other efforts. Picking at spots or marks restarts the whole inflammatory cycle. And piling on too many strong actives at once irritates the skin, which for Asian skin types is the fastest route to fresh pigmentation.
If your marks are deep, raised, or indented rather than flat, or if they are not improving after several months of consistent care, see a dermatologist. Some marks benefit from in clinic treatments, and true scars are a different concern that needs professional assessment.
Sources
Published dermatology literature on post inflammatory erythema and post inflammatory hyperpigmentation; clinical research on pigmentation in Fitzpatrick III-VI skin; American Academy of Dermatology guidance on acne and post acne marks.
Frequently Asked Questions
What is the difference between PIE and PIH?
Which is more common in Asian skin, PIE or PIH?
How long do PIE and PIH take to fade?
Can you treat PIE and PIH at the same time?
Post-acne marks often linger in your mind more than on your skin, and you can explore the self-confidence side of clear skin with the free psychology quizzes at Decode Within.