Post inflammatory erythema (PIE) is a common but often overlooked sign of skin inflammation. Often overshadowed by its more famous cousin, post inflammatory hyperpigmentation, PIE is a cosmetic concern for many and deserves its share of discussion. In this post we explore what causes post inflammatory erythema, how it differs from PIH and the best treatments for it.
What is Post Inflammatory Erythema?
Post inflammatory erythema is the result of a complex series of events in the skin. It is triggered mainly by inflammation and is common following acne. It presents as a rash of reddish or pinkish spots. These are not pigment deposits, but evidence of blood vessel changes underneath the skin. They signal a particular phase of skin healing. Essentially, PIE is a visual reminder of previous inflammatory activity. It highlights the delicate balance between healing and lasting changes in the skin’s appearance.
When the skin suffers an injury, such as from acne, harsh treatments or physical trauma, it responds with inflammation. This is a natural part of healing. Blood flow to the area increases as the body tries to repair the damage. This brings a surge of white blood cells and inflammatory mediators. These are vital for healing. However, they can also cause collateral damage. As the inflammation settles, it can leave behind dilated blood vessels or microvascular damage in the deeper layers of the skin. These vessels are unable to shrink back to their original size, so they remain more visible through the skin’s surface. They appear as the stubborn red or pink marks we call post inflammatory erythema.
What Causes Post Inflammatory Erythema?
As noted above, post inflammatory erythema is mainly due to an inflammatory response in the skin. Whilst PIE can occur in all skin tones, it is often more visible in fairer skin. This is because the contrast between the redness and the nearby skin is greater.
Various factors can trigger this inflammation, with acne being one of the most common. When acne lesions heal, they often leave behind red or pink marks, sometimes called post-acne erythema. Other causes include physical trauma to the skin, such as cuts, burns or harsh treatments like aggressive exfoliation or laser procedures. Dermatological conditions like rosacea or contact dermatitis can also lead to PIE, as these involve persistent inflammation. In essence, any skin injury or condition that causes inflammation can potentially cause PIE. This makes it a relatively common and sometimes unavoidable problem. That said, although these factors raise the risk, PIE can occur in anyone. Its appearance varies with skin type and tone.
What’s the Difference Between PIE & PIH?
PIE and PIH are often confused because both stem from skin trauma or inflammation. However, they are separate conditions that need to be treated differently. The key difference is the cause. PIE is vascular. Damaged or dilated capillaries show up as red or pink marks, and it is more common in lighter skin. PIH is pigmentary. Excess melanin shows up as brown, black or blue-grey marks, and it is more common in darker skin tones. Because they respond to very different treatments, it helps to tell them apart. We explain how to tell PIE and PIH apart and treat each in a separate guide.
Best Treatments for Post Inflammatory Erythema
Treating post inflammatory erythema needs a multi-faceted approach that targets both the inflammation and the vascular changes. In practice, treatment falls into three strands:
- Topical skincare: niacinamide and azelaic acid are useful first steps. Niacinamide is a potent anti-inflammatory that reduces redness and improves skin barrier function. Azelaic acid soothes inflammation and offers gentle exfoliation, which helps the marks fade gradually. Retinoids like tretinoin speed up cell turnover and help prevent the breakouts and red marks of post-acne erythema. They need caution in sensitive or inflamed skin, or if you are managing rosacea. This is because they can cause irritation, purging and dryness.
- Professional treatments: pulsed dye laser is one of the most effective options, as it targets and shrinks the dilated blood vessels behind the redness. IPL is another option. For stubborn cases, microneedling can stimulate collagen and skin regeneration. A dermatologist can help you decide which is best for your skin.
- Prevention: managing the underlying cause, especially acne, is key. Adopt a gentle routine, avoid irritants, protect your skin from the sun, and introduce actives like retinoids slowly so you do not worsen the redness.
Post inflammatory erythema is not harmful, but it is a cosmetic concern for many. It is normally not permanent, though it can be persistent if left untreated. There are a number of treatments for it. However, preventing causative factors like acne is key to managing it. As with any skin concern, the right approach depends on your skin type, the extent of your PIE and your goals. Whichever treatment you choose, you will need to be patient and consistent for the best results.
At City Skin Clinic, we are passionate about personalised skincare. Through our online skin clinic we connect clients with our doctors for safe and effective treatments with ingredients like tretinoin and hydroquinone. We treat skin conditions like acne, hyperpigmentation, melasma and skin ageing. To get started on your personalised skin protocol, book a virtual video consultation or use our online consultation form. The journey towards great skin starts here.
This article is intended for general informational purposes only and is not a substitute for medical advice, diagnosis or treatment. Always consult a qualified medical professional with any concerns about your skin or treatment options.
