Acne Scars: PIE, PIH, and Atrophic Scars
Prepared by Pharmacist Berfin Işık. As a pharmacist specializing in pharmaceutical and cosmetic formulations, she follows the latest scientific literature on post-acne mark management. This content is for informational purposes only and does not constitute medical advice.
Acne marks are not uniform; what most people call a "mark" is actually one of three different conditions, and each requires a completely distinct solution: red marks (PIE), brown marks (PIH), and permanent pitted marks (atrophic). In this guide, we discuss how to differentiate between the three and how to approach each from a pharmacist's perspective.
First, Let's Differentiate: Three Different Types of Marks
Acne, in all its lesions — from microcomedones to boils, "post-inflammatory" redness and spots — is a disease involving inflammation. The mark it leaves behind after the inflammation subsides can vary:
- PIE (Post-Inflammatory Erythema): Pink-red, sometimes purple, flat marks. They are vascular in origin, resulting from superficial capillaries that dilated during inflammation. Common particularly in lighter skin tones. They blanch when pressed with glass.
- PIH (Post-Inflammatory Hyperpigmentation): Flat light to dark brown spots. Caused by melanin accumulation; especially common in darker skin tones and worsened by sun exposure.
- Atrophic Scars: Permanent indentations/tissue loss on the skin surface. According to classical classification, they are divided into three types: icepick, rolling, and boxcar. This is a texture issue, not a color issue.
This distinction is critical: while PIE and PIH can significantly fade over time with proper topical care, atrophic scars are permanent structural changes and usually require professional procedures.
Summary Table
| Mark Type | Appearance | Approach |
|---|---|---|
| PIE (red) | Pink-red flat mark, vascular | Soothing + barrier repair (niacinamide, azelaic, cica), SPF; vascular laser for stubborn cases |
| PIH (brown) | Brown flat spot, melanin | Pigment-targeting actives (niacinamide, tranexamic, azelaic, vitamin C, arbutin) + retinoid + strict SPF |
| Atrophic (pitted) | Permanent indentation/tissue loss | Professional procedures (microneedling, subcision, laser, fillers, peels); topical support |
How to Manage PIE (Red Marks)?
The basis of PIE is inflammation and vascular response; therefore, the priority is to soothe inflammation and repair the barrier. Anti-inflammatory actives such as niacinamide, azelaic acid, and Centella reduce redness. The most critical step is to prevent new acne lesions and thus new PIE; topical retinoids target both acne and inflammation in this regard. Sun protection prevents redness from lasting longer. Vascular lasers are effective for stubborn PIE.
How to Manage PIH (Brown Marks)?
PIH is a melanin issue; the solution lies in actives that target pigment production. Topical retinoids both treat acne and reduce pigmentation; early initiation is especially recommended for dark marks due to acne. Tyrosinase-targeting ingredients such as niacinamide, tranexamic acid, azelaic acid, vitamin C, and alpha arbutin even out skin tone. Sun protection is arguably the most important step for PIH; UV exposure darkens existing spots and can nullify treatment efforts. We covered all actives for spot management in our spot and hyperpigmentation guide, and azelaic acid in detail in our separate article.
Atrophic Scars: Are Topicals Sufficient?
Atrophic scars (icepick, rolling, boxcar) are permanent tissue loss; topical products alone cannot fill these indentations. Scientific reviews indicate that professional procedures such as microneedling, subcision, fractional laser, fillers, and chemical peels are essential for atrophic acne scars. Topical retinoids and glycolic acid can support these procedures by promoting tissue regeneration but cannot replace them. We discussed which procedure is appropriate when in our guide to interventional skin care procedures.
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Frequently Asked Questions
Do I have red marks or brown marks? How can I tell?
A simple test: gently press the mark with a glass or your finger. If the redness temporarily blanches, it's a vascular PIE. If the color doesn't change and remains brown, it's melanin-based PIH. If there's an indentation, we're talking about an atrophic scar.
Do acne marks disappear on their own?
PIE and PIH mostly fade within months; proper actives and sun protection accelerate this process. Atrophic scars, however, are permanent structural changes and do not improve on their own; they require professional procedures.
How can I prevent marks from forming?
The most effective "mark treatment" is prevention: managing acne early and correctly, not picking at pimples, and using sun protection. Picking pimples increases inflammation and raises the risk of both PIH and atrophic scars.
Does sunscreen really make a difference?
Yes, especially for PIH, it's decisive. UV exposure darkens existing spots and can nullify months of treatment. Broad-spectrum SPF is the invisible but most critical step in mark treatment.
Conclusion
The first step in properly managing acne marks is to correctly identify which type of mark you're dealing with: red (PIE) requires soothing, brown (PIH) requires pigment-targeting actives and strict SPF, and pitted (atrophic) scars require professional procedures. For a mark care plan tailored to your skin, you can seek support from Medicblu experts.
References
- Dreno B, Gollnick HPM, Kang S, et al. Understanding innate immunity and inflammation in acne: implications for management. J Eur Acad Dermatol Venereol. 2015;29(Suppl 4):3-11. PMID: 26059728 · DOI: 10.1111/jdv.13190
- Callender VD, Baldwin H, Cook-Bolden FE, et al. Effects of Topical Retinoids on Acne and Post-inflammatory Hyperpigmentation in Patients with Skin of Color. Am J Clin Dermatol. 2022;23(1):69-81. PMID: 34751927 · DOI: 10.1007/s40257-021-00643-2
- Boen M, Jacob C. A Review and Update of Treatment Options Using the Acne Scar Classification System. Dermatol Surg. 2019;45(3):411-422. PMID: 30856634 · DOI: 10.1097/DSS.0000000000001765
