In acne management, the immediate priority is usually to control active breakouts and prevent future flare-ups. Yet, achieving truly successful outcomes requires going beyond the resolution of spots to address the marks they leave behind. Among the most persistent and frustrating of these is Post-Inflammatory Erythema (PIE), red or pink patches that remain once an inflammatory acne lesion has healed. Unlike pigmentation changes, PIE results from dilated or damaged capillaries and small blood vessels close to the skin’s surface.
Even after the skin is free of active blemishes, these marks can endure for months or even years, subtly but significantly affecting skin tone and overall appearance. This is not just a cosmetic matter; untreated PIE can impact self-confidence and make the complexion appear uneven long after the acne itself has resolved. Addressing PIE early is therefore a critical, but often underestimated, part of comprehensive acne care, as it helps restore uniformity to the skin, reduces the psychological burden, and helps patients achieve a true sense of recovery.
Drawing on over a decade of experience treating thousands of acne patients across a wide range of severities, we present here a real-world case study. This example follows one patient’s journey, from diagnosis through treatment to outcomes, illustrating the importance of recognising and managing PIE as an integral step in acne treatment planning.
AB is a 32-year-old female banking executive who presented to the clinic with concerns about persistent acne and accompanying red marks. Her symptoms began following a winter holiday in Japan, during which she experienced a flare-up of acne. Initially, she attributed the outbreak to temporary environmental changes and did not seek medical attention. However, after three months without improvement, despite consistent use of over-the-counter remedies such as niacinamide creams and salicylic acid face washes, she decided to consult for further assessment.
AB has no significant medical history and is not currently taking any medications. She reports a history of teenage acne, which had largely resolved by the time she completed university.
On examination, there were multiple inflammatory papules, pustules, and comedones distributed over the forehead, temples, and cheeks. There was no clinical evidence of nodules, cystic lesions, or truncal involvement. Several small erythematous macules consistent with post-inflammatory erythema (PIE) were noted in proximity to active lesions, with some displaying early atrophic changes.
Using the validated Investigator’s Global Assessment (IGA) scale, her presentation was graded as Grade 3 (Moderate), reflecting the number and type of acneiform lesions present at the time of review.
| Grade | Clinical Description |
| 0 | Clear skin with no inflammatory or noninflammatory lesions |
| 1 | Almost clear; rare noninflammatory lesions with more than one small inflammatory lesion |
| 2 | Mild severity; greater than grade 1; some noninflammatory lesions with no more than a few inflammatory lesions (papules/pustules only, no nodular lesions) |
| 3 | Moderate severity; greater than grade 2; up to many noninflammatory lesions and may have some inflammatory lesions, but no more than one small nodular lesion |
| 4 | Severe; greater than grade 3; up to many noninflammatory and inflammatory lesions, but no more than a few nodular lesions |
AB was diagnosed with moderate inflammatory acne vulgaris, accompanied by post-inflammatory erythema (PIE) and early atrophic acne scarring. The diagnosis was based on her clinical presentation and examination findings. Differential diagnoses were considered: fungal acne (pityrosporum folliculitis) was excluded due to the presence of comedones, lesion morphology, and absence of pruritus, while rosacea was ruled out owing to the presence of comedones, lack of telangiectasia, and no history of facial flushing.
Given the combination of active acne, PIE, and early scarring, a multi-pronged approach was initiated:
AB experienced mild skin dryness, redness, and peeling with the topical regimen, mitigated by gradual introduction to reduce retinoid-associated dermatitis. No side effects were reported from oral antibiotics.
For maintenance, AB was advised to continue topical retinoid therapy to reduce recurrence risk and sustain result
Managing acne that presents with post-inflammatory erythema (PIE) requires a multi-modal strategy, integrating oral medications, topical treatments, and targeted in-clinic procedures. Addressing both active inflammation and its vascular aftermath is essential to prevent long-term pigmentation changes and scarring.
Research shows that over 80% of acne scars develop from lesions preceded by post-acne erythema. The longer an inflammatory papule persists untreated, the greater the likelihood of permanent textural change. For patients presenting with active acne and PIE, timely intervention is critical and treatment plans must be individualised, taking into account medical history, skin tolerance, and lifestyle considerations.
PDL is an effective adjunct in managing both active inflammatory acne and PIE. It works on the principle of selective photothermolysis, delivering light at a wavelength (585–595 nm) that specifically targets haemoglobin in the skin, allowing precise treatment without damaging surrounding tissues. Its therapeutic effects include:
The optimal treatment window for PIE is early, while vascular changes are still recent, and the skin’s healing response is active. Acting during this phase allows for maximum impact from vascular-targeted interventions like PDL. Delayed treatment, after PIE has been present for months or years, can make resolution significantly slower and more challenging.
This case highlights the value of integrating post-inflammatory erythema (PIE) management into the earliest stages of acne treatment. By addressing active inflammation and vascular changes simultaneously, we not only improved the patient’s skin clarity but also reduced the risk of long-term scarring and uneven pigmentation. The combination of targeted oral and topical therapies with pulsed dye laser intervention delivered both functional and cosmetic benefits, restoring skin health and confidence.
A proactive, multi-modal approach ensures that treatment is not limited to clearing active breakouts, but also focuses on preventing the lasting visual impact of acne. For patients, this means faster recovery, more even skin tone, and a better quality of life.
If you are struggling with persistent acne or lingering red marks after breakouts, schedule a consultation with our dermatology team at APAX clinic to explore tailored treatment strategies that address both active acne and its aftermath.
All patient details in this case study have been fully anonymised to safeguard privacy. No actual names or initials are used, and any resemblance to real individuals is purely coincidental. Images included are for illustrative purposes only and do not depict the actual patient. Treatment responses vary from person to person, and the outcomes described here are specific to this case; they should not be interpreted as a guarantee of similar results.
This case study is intended solely for informational and educational purposes and does not constitute medical advice. Patients should always seek assessment and guidance from a qualified healthcare professional for their own condition.
Dr. Moses Ng is a distinguished professional in the field of aesthetic medicine, renowned for his expertise in advanced cosmetic procedures. With over 15 years of experience, extensive training and a keen eye for detail, Dr. Ng specializes in a wide range of treatments, including injectables, laser therapies, and acne scar management.
Dr. Moses Ng’s commitment to excellence and patient-centric approach have earned him a reputation as a trusted clinician in aesthetic medicine. His continuous pursuit of the latest advancements in the field ensures that his patients receive the highest standard of care and the most effective treatments available.
