Many people who have had acne no longer report active blemishes, but rather red or dark spots that simply won't go away. This is precisely where frustration often arises – and a key mistake:
These stains are treated the same, even though they do not have the same cause .
In dermatology, a clear distinction is made between PIE and PIH . Understanding these differences allows for more targeted skincare and helps avoid unnecessary irritation.
Red spots after acne: What is PIE?
PIE (Post-Inflammatory Erythema) describes red, pink, or light purple spots that remain after inflammatory acne.
These spots are not caused by pigment, but by dilated or damaged blood vessels in the skin. PIE is particularly common in people with lighter skin tones.
Important to know:
PIE is not a pigment spot . Brightening products alone will therefore not solve the problem – on the contrary, they can even worsen the redness.
Dark spots after acne: What is PIH?
PIH (Post-Inflammatory Hyperpigmentation) appears as a brown, grey-brown or yellowish discoloration.
Here, the skin reacts to inflammation with an overproduction of melanin . UV radiation significantly intensifies this process, which is why PIH often remains visible for months without protection.
PIH occurs particularly frequently in medium to darker skin types, but can basically affect any skin type.
Why correct classification is crucial
A very common misconception is:
"Acne spots are always pigment spots."
That is not technically correct.
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PIE = Vascular reaction
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PIH = Pigment reaction
Treating red spots like age spots risks a longer healing time. Conversely, PIH requires targeted medications to visibly recede.
How to properly maintain PIE
In PIE, the focus is on calming the skin . The goal is to reduce inflammation and stabilize the skin barrier.
The following have proven particularly effective:
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Niacinamide in moderate doses (e.g., AXIS-Y Dark Spot Correcting Glow Serum 50ml )
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Azelaic acid with anti-inflammatory properties (e.g. ANUA Azelaic 10 Hyaluron Redness Soothing Pad )
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Centella Asiatica (Cica) (e.g.SKIN1004 Madagascar Centella Ampoule)
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Panthenol and barrier-strengthening lipids (e.g. Numbuzin No.1 Pantothenic B5 Active Soothing Cream 80ml )
This is precisely where soothing, sensitive skincare, as often found in Korean cosmetics, comes in. Mild formulations and a slow release of active ingredients are crucial for PIE (Peak Intolerance).
However, aggressive peels or frequent exposure to irritants can prolong the redness.
How PIH can be treated effectively
In PIH, the focus is on regulating melanin production . The skin needs patience, consistency, and protection.
Commonly used active ingredients include:
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Tranexamic acid (e.g. ANUA Niacinamide 10% + TXA 4% Serum 30ml )
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Alpha-Arbutin (e.g. Beauty of Joseon Glow Deep Serum: Rice + Arbutin 30ml )
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Niacinamide (e.g. Jumiso Niacinamide 20 Serum 40ml )
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Retinoids (e.g. K-SECRET – SEOUL 1988 Serum: Retinal Liposome 2% + Black Ginseng 30ml )
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Vitamin C (e.g. Dr. Althea Vitamin C Boosting Serum 30ml )
Serums with clearly defined active ingredient concepts are particularly useful here, as they can specifically target pigmentation processes.
Sun protection – the most important step in PIE and PIH
Regardless of whether the spots are red or dark:
Both conditions demonstrably worsen without daily sun protection .
UV radiation:
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Increased redness in PIE
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activates melanin production in PIH
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prolongs the time until visible improvement
Consistent sun protection is therefore not an optional addition, but an integral part of every routine.
Conclusion
PIE and PIH look similar at first glance, but are based on fundamentally different mechanisms .
A noticeable improvement does not come from having as many products as possible, but from:
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the correct classification of the stains
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a calm, barrier-free care
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consistent sun protection
Those who follow these basic principles give their skin the best conditions to regenerate sustainably.
