If you have ever had a bad acne break out, you may have noticed that it can sometimes leave marks on your skin. These marks can be either pink/red or brown in color but don’t tend to cause textural irregularities like true acne scars.
Post inflammatory erythema (PIE) = red/pink acne marks
Post inflammatory hyperpigmentation (PIH) = brown acne marks
What Causes Post Inflammatory Erythema?
Post inflammatory erythema is an end-point of the acne pimple life cycle where:
- Your hormones cause your oil glands to overproduce oil
- Dead skin cells block your pores and trap this oil inside
- Bacteria (p.acnes recently reclassified to c.acnes) feed off of this oil and rapidly multiply
- Inflammation occurs
- Your body senses the increase in bacteria and sends white blood cells in to fight it
- The white blood cells kill the bacteria and then die themselves (dead white blood cells are what we see as ‘pus’)
- The dead white blood cells/pus are either absorbed and broken down by your body or released when you pick or squeeze a spot. However, inflammation still remains. Picking and/or squeezing may also leave behind an open wound.
- The wound healing process begins and new collagen is produced (too much collagen = hypertrophic ‘raised’ acne scars, too little collagen = atrophic ‘pitted’ acne scars).
- The remaining inflammation may cause the production of melanin in the affected area (PIH) in darker skin. In fair skin, the blood vessel dilation associated with wound healing is much more visible and visible as red marks (PIE)
Acne and post inflammatory erythema are also associated with a damaged skin barrier.
How To Tell If It’s Post Inflammatory Erythema or Hyperpigmentation
Although unscientific, there is a simple at-home test you can do to work out whether what you’re experiencing is post inflammatory erythema or hyperpigmentation – press your finger on it!
If the mark disappears then it is most likely post inflammatory erythema, if it stays then it’s more likely to be hyperpigmentation.
Acne, Post Inflammatory Erythema, & Your Skin Barrier
Your skin barrier (stratum corneum) regulates water in and out of your skin and protects your body from external pollutants and irritants.
When your skin barrier is damaged, the water within your skin that keeps it nice and hydrated can escape and irritants can enter – leaving your skin dehydrated and irritated.
Your stratum corneum has a ‘bricks-and-mortar’ like structure where your skin cells (the bricks) are held together by a glue-like mixture of lipids (the mortar) to create a waterproof barrier. This mixture of lipids is referred to as your ‘lipid matrix’ and contains a mix of ceramides, cholesterol, and fatty acids.
When any of these lipids are depleted (usually from over-exfoliating, too many active ingredients, or harsh cleansers), gaps form in your skin barrier, and water can escape.
Studies have found that skin barrier damage and reduced skin hydration is often seen alongside acne. In fact, one study found that skin hydration was negatively correlated with acne severity – meaning that the more severe your acne is, the more dehydrated your skin may be!
Other research has shown that acne is associated with reduced levels of ceramides and fatty acids (particularly linoleic acid).
Similarities Between Rosacea and Post Inflammatory Erythema
Another skin condition associated with skin barrier damage is rosacea – a skin condition characterized by facial redness and sensitivity, and usually only seen in fair skin.
Although rosacea and post inflammatory erythema are completely different skin conditions, there are similarities in their presentation.
For example, the redness in both post inflammatory erythema and rosacea is due to visible blood vessel dilation. In post inflammatory erythema, this is due to the wound healing process while, in rosacea, this is due to environmental factors or other triggers.
Because of this, skincare products that help improve rosacea may also improve post inflammatory erythema.
In addition, research has demonstrated that skincare treatments that improve skin barrier function can also improve the redness and inflammation seen in rosacea.
How To Treat Post-Inflammatory Erythema
In order to treat post inflammatory erythema, you should look for skincare ingredients/products that:
- Repair your skin barrier
- Reduce inflammation
- Reduce blood vessel dilation
Niacinamide
Niacinamide (vitamin B3) is an antioxidant that offers a wide range of benefits for your skin including:
- Boosting collagen production
- Brightening skin and reducing hyperpigmentation
- Reducing inflammation
- Fighting acne
- Boosting skin hydration
Some research suggests that niacinamide boosts your skin’s hydration by encouraging the production of the lipids naturally found within your lipid matrix. This means that it can help repair your skin barrier.
In one study, a niacinamide-containing moisturizer increased skin hydration and reduced facial redness at the same time. Other research has also found moderate improvements in facial redness with the use of niacinamide.
Niacinamide is a great option for treating post inflammatory erythema, especially if you are also experiencing acne, post inflammatory hyperpigmentation, or are concerned about aging.
Bear in mind that the niacinamide used in research studies is usually around 4-5% concentration while some of the more popular niacinamide serums contain 10% – this may be why some people find that their skin breaks out when using niacinamide.
Vitamin C
Vitamin C is the most abundant antioxidant in your skin and it is absolutely essential for collagen production. It also helps to:
- Brighten skin
- Reduce hyperpigmentation
- Improve fine lines and wrinkles
- Reduce Inflammation
It also helps to form and regulate the lipids within your skin’s barrier.
Research has shown that vitamin C can reduce facial redness by 21% in six weeks, as well as treating visible blood vessels and capillaries.
Azelaic Acid
Azelaic acid has anti-inflammatory, antioxidant, and antibacterial effects, which has led to its wide-use for skin conditions such as acne and rosacea.
It’s well-known for effectively reducing facial redness, with research demonstrating reductions of 44 – 70%.
Ceramides, Cholesterol, & Fatty Acids
What better way to improve your skins barrier than to replace the very thing it’s missing – lipids.
One clinical study demonstrated that a cream containing ceramides, cholesterol, and fatty acids improved skin barrier function within 30 minutes of application, with longer use also reducing facial redness.
Ceramides also help reduce skin inflammation which makes them an ideal treatment for post inflammatory erythema.
Aloe Vera
If you’ve ever experienced sunburn, then you’re probably familiar with aloe vera – a plant extract commonly used to soothe irritated skin. Aloe contains vitamins (A, C, & E), saponins, amino acids, and is:
- Hydrating
- Anti-inflammatory
- Anti-bacterial
Research suggests that aloe can reduce acne-related facial redness as well as the redness, irritation, and inflammation experienced in irritant dermatitis.
Green Tea
Green tea contains a number of polyphenols (plant antioxidant molecules) that help to reduce inflammation and facial redness – particularly epigallocatechin-3-gallate (EGCG).
A number of clinical studies have highlighted that EGCG is an effective treatment for acne through its anti-inflammatory effect, which suggests that it may help improve post inflammatory erythema as well.
However, while a small study found that EGCG reduced inflammation and blood vessel dilation, there was no overall reduction in facial redness.
Cytokinins
Cytokinins, or plant hormones, are relatively unknown and underrated skincare ingredients that have anti-inflammatory and antioxidant effects.
Research suggests that cytokinins can improve facial redness in as little as two-weeks and one clinical study found that improvements in facial redness coincided with improvements in skin barrier function.
Centella Asiatica
Centella, or ‘Cica’, is a plant extract native to South East Asia and has been made popular by K-Beauty brands for its antioxidant, anti-inflammatory, and healing skin benefits.
In terms of post inflammatory erythema, centella has been found to increase skin hydration and the levels of antioxidants within your skin, both of which can help reduce inflammation and redness.
In fact, research has found that centella extracts improve acne-related redness, as well as the redness and inflammation caused by eczema and other inflammatory skin conditions. These anti-redness results appear to be down to the ingredients hydrating effect.
Snail Mucin
Another skincare ingredient made popular by K-Beauty brands is snail mucin or ‘slime’ which contains allantoin, hyaluronic acid, and glycolic acid, among other beneficial components.
Multiple research studies have found snail slime to be highly effective at treating radiation burns due to its ability to reduce inflammation and improve wound healing. It is also very good at increasing skin hydration.
You can read about these skincare ingredients in more detail here.
Laser Treatments
Laser treatments use focussed beams of light to target various substances within your skin, such as water, melanin, and hemoglobin (the substance that makes your blood red).
When the light energy from the laser is absorbed by these molecules, it is transformed into heat and breaks down the substance. This process is known as ‘thermolysis’. Each molecule selectively absorbs a specific wavelength of light.
In the case of post inflammatory erythema, the substance you want a laser to target is the hemoglobin within the small blood vessels in your skin. Lasers that do this are called ‘vascular lasers’.
Vascular lasers heat the small blood vessels within your skin which destroys the vessel walls and coagulates (clots) the blood inside. Your body then breaks down the old coagulated blood and absorbs it back into your bloodstream so that it can be excreted. This is similar to how a bruise heals.
The gold-standard laser treatment for post-inflammatory erythema is the Pulse-Dye Laser (PDL) but the Potassium Titanyl Phosphate (KTP) laser is similarly effective.
Both of these vascular lasers have a wavelength that falls into the yellow-green range of the light spectrum and is selectively absorbed by the oxygenated hemoglobin (oxyhemoglobin) within your blood.
PDL
As well as treating redness, PDL is effective at treating acne and acne scarring.
Research has demonstrated that PDL can improve scarring, as well as the redness associated with scarring, by up to 68% after one-to-two treatments.
Improvements to post inflammatory erythema were described by 75% of patients as either ‘good’ or ‘excellent’. Other research has seen improvements in 90% of patients with two treatments spaced 4-weeks apart. Specifically, the number of red marks were reduced by 25% after one treatment and by 58% after two treatments.
KTP
The KTP laser has a shorter wavelength than the PDL laser and doesn’t penetrate as deeply into your skin. This makes it more useful for treating the residual redness from the blood vessels closer to the surface of your skin.
In a clinical study, the KTP laser was as good as the PDL laser at reducing the redness of surgical scars.
IPL
IPL (Intense Pulsed Light) is not a true laser as it is made up of multiple wavelengths of light (white light) rather than one specific wavelength. This makes it a bit of a ‘jack of all trades’ in that it can treat multiple skin conditions at the same time but ‘master of none’ in that it is less effective at treating any one condition.
IPL can be used to treat post inflammatory erythema but it usually takes multiple treatments to see any significant results.
Other lasers, such as Nd:YAG and fractional lasers can also offer improvements to post inflammatory erythema.
Other Tips For Getting Rid of Post Inflammatory Erythema
- Don’t pick! – Squeezing and picking at your spots increases inflammation and creates a bigger wound in need of healing. Not only does this mean that your post inflammatory erythema may be visible for longer but you’re also increasing your risk of developing pitted acne scars!
- Wear sunscreen every day – The UV radiation from the sun can increase blood vessel dilation and lead to broken capillaries which will make post inflammatory erythema appear worse.
- Moisturize – Dehydrated skin and inflammation often go hand-in-hand. Regularly moisturizing your skin can help to keep inflammation at bay.
- Be patient – Post inflammatory erythema will eventually go away on its own, even if you do nothing! However it can take some time to do so. Skincare products can help resolve post inflammatory erythema faster, but laser treatments are the quickest fix (although they are also the most costly).
Summary
Post inflammatory erythema refers to the red marks left behind after acne clears. It is temporary and will eventually go away on its own but there are a few skincare ingredients and laser treatments that can speed up the process.
