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Dr. Alpana Mohta Ranka, MD, DNB, IFAAD, is a triple-board-certified dermatologist with over 100 research publications in peer-reviewed scientific journals.


Post Inflammatory Erythema: A Comprehensive Guide to Understanding and Managing PIE

Have you ever noticed those pesky red marks left behind after a pimple goes away? We call them post inflammatory erythema, or PIE. It is a common skin issue seen following acne or other skin inflammations.

Characterized by red or pink spots, post inflammatory erythema is different from post inflammatory hyperpigmentation (PIH) from acne, which causes dark spots due to excess melanin. In this article, we will cover its causes, symptoms, and effective treatments to help manage and prevent this condition.

What is Post Inflammatory Erythema?

Researchers have observed that skin discoloration after inflammation usually appears as dark spots in people with darker skin tones. This discoloration shows up in people with lighter skin tones as red or pink spots. To describe these marks left on the skin after inflammation, the term "post inflammatory erythema" (PIE) was proposed by a group of dermatologists from Boston University in 2013. 

Post Inflammatory Erythema
The arrows point at post inflammatory erythema caused due to acne

Post inflammatory erythema happens when tiny blood vessels called capillaries in the very top layer of the skin, known as the epidermis, get damaged or dilated during the healing process. This causes the skin to look red. The epidermis is also thinner and more see-through while it’s healing, which makes the redness more noticeable. This redness is widespread in individuals with lighter skin tones but can affect anyone.

Causes of Post Inflammatory Erythema

Symptoms of Post Inflammatory Erythema

The main symptom of post inflammatory erythema is the presence of flushed red, maroon, or pink spots on the skin where acne lesions or skin injuries were previously located. These marks become pronounced after sun exposure, physical activity, or temperature changes (too hot or too cold environments).

Treatment Options for Post Inflammatory Erythema

Treating post inflammatory erythema requires patience and a combination of OTC and prescription treatments:

At-Home Treatments

Topical Products

  • Niacinamide: Known for its anti-inflammatory properties, niacinamide helps reduce redness and strengthen the skin barrier. Clinical studies have found that topical niacinamide is as effective as clindamycin for treating acne vulgaris due to its anti-inflammatory effects. Niacinamide also has antimicrobial activity against Cutibacterium acnes (an acne-causing bacteria).

  • Azelaic Acid: In a 2024 study involving patients with mild to moderate acne, significant improvement in post inflammatory erythema and PIH was observed after 12 weeks of treatment, with 15% azelaic acid applied twice daily. Azelaic acid reduces redness and improves skin texture. It acts as an anti-inflammatory and can be found in OTC or as a prescription compounded medication.

  • Tranexamic Acid: As noted in an article from the world-renowned Journal of the American Academy of Dermatology, tranexamic acid reduces redness by blocking the formation of inflammatory substances like IL-6 and TNFα in our body. This blockage reduces the dilatation of blood vessels and stops the formation of new blood vessels over the site of post inflammatory erythema.

  • Retinol and Retinaldehyde: If you have acne and experience redness from prescription retinoids, consider switching to milder agents like retinol or retinaldehyde. Retinol helps reduce post inflammatory erythema by promoting cell turnover and collagen production, which fade redness due to inflammation.

My Top Recommendations for Topical Treatments that can be used at Home

  • Sesderma Azelac Ru Serum: This serum contains azelaic acid, tranexamic acid, retinol, and vitamin C. While multiple actives usually can't be combined in one product due to risks of deactivation or irritation, this serum uses nanotechnology to create liposomal particles. This ensures the stability of all four active ingredients without causing irritation, even for sensitive skin.

  • Anua Dark Spot Correcting Serum: It has a combination of 10% Niacinamide with 4% Tranexamic Acid. Both are clinically proven to fade red marks left behind after acne or injury.

  • Naturium Tranexamic Topical Acid 5%: It combines tranexamic acid with niacinamide and vitamin C to target dark spots and improve skin tone.


Daily use of broad-spectrum fragrance-free sunscreen with SPF 50 or higher is crucial to prevent further damage and aid in fading post inflammatory erythema marks. Sunscreen prevents the darkening of marks and protects the skin from UV rays that can exacerbate the redness.

Professional Treatments

  1. Topical Medications: Prescription treatments like oxymetazoline, brimonidine tartrate, and timolol have been clinically proven to treat post inflammatory erythema in healing acne lesions.

  2. Laser Therapy: Pulsed dye laser (PDL) targets blood vessels, reducing redness. IPL (Intense Pulsed Light) therapy and Nd:YAG laser can also help improve skin texture and reduce redness.

  3. Microneedling: This involves pricking the skin with tiny needles, stimulating collagen production, and improving skin texture. It can be used in combination with topical medications like Tranexamic acid. Microneedling with radiofrequency (MnRF) devices has also been found to help manage residual erythema left behind in healing acne marks.

  4. Chemical Peels: Superficial chemical peels can help reduce redness by peeling away the top layers of the skin. Options include glycolic acid, salicylic acid, and trichloroacetic acid (TCA) peels.

Natural Remedies

  1. Aloe Vera: Known for its soothing properties, aloe vera can help reduce redness.

  2. Green Tea Extract: Its anti-inflammatory properties can calm irritated skin.

Preventive Measures for Post Inflammatory Erythema

  • Treat Your Active Acne: Proactive treatment of active acne is the best way to prevent the formation of post inflammatory erythema. If you only have a few active acne, you can go for spot-application treatments. For more widespread and moderate-to-severe acne, it's best to consult your dermatologist to get a personalized treatment and skincare routine. Avoid Picking at Skin: Picking or squeezing pimples can damage capillaries and worsen the erythema.

  • Gentle Skincare Routine: Use mild, non-irritating products to avoid further inflammation.

  • Sun Protection: Consistent use of sunscreen prevents further damage and helps the red marks fade faster.

  • Regular Moisturization: Keeping the skin hydrated promotes healing and reduces redness.

When to See a Dermatologist

If over-the-counter treatments and home remedies don’t improve your post inflammatory erythema, it’s essential to consult a dermatologist. They can offer professional treatments and tailor a skincare regimen to your needs.


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