We previously discussed the various different laser treatment options for Post Inflammatory Erythema (PIE). However, laser treatments are often costly and may come with downtime and undesirable side-effects. It is often thought that the only treatment for PIE is time, however, while post inflammatory erythema will indeed fade away eventually, there are a number of topical treatments that can improve the appearance of PIE and fade it faster.
To refresh your memory, Post Inflammatory Erythema (PIE) is a relatively new term used to describe the erythema (redness) that occurs after inflammatory acne. It is considered a form of acne scarring but is different from post-inflammatory hyperpigmentation (PIH), atrophic scars, and hypertrophic scars .
First things first, let’s quickly clarify what causes acne…
Acne is primarily an inflammatory disease  caused by multiple overlapping factors:
- Overproduction of oil
- A build-up of dead skin cells
- P-acnes bacteria
Related Reading: 4 Main Causes of Acne
Basically, hormones can cause the sebaceous glands to overproduce sebum as well as causing an abnormal build up of epithelial (skin) cells. The excess skin cells block the hair follicles, trapping the oil within. The p-acnes bacteria that live within the oil glands feed off of this excess oil and multiply which causes an inflammatory response.
Inflammation begins with the clogged pore, continues throughout the acne lesions life-cycle, and remains even after the acne lesion has cleared. Post-acne inflammation is visible in individuals with dark skin as brown marks (PIH) and in individuals with fair skin as red marks (PIE) .
It is thought that both PIE and PIH may be partly due to the slow break-down of the non-surviving p-acnes bacteria in the hair follicle . Additionally, Post Inflammatory Erythema is a result of the blood vessel dilation associated with wound-healing. The appearance of which is worsened by the fact that the skin is thinner during the healing process .
Skin Barrier Function in Acne, Post Inflammatory Erythema, and Other Facial Erythema
Some evidence has supported the idea that acne is associated with abnormalities in epidermal barrier functions. Furthermore, some common acne treatments can disrupt the normal functions of the epidermis, including the stratum corneum.
Since acne is the precursor to Post Inflammatory Erythema, it is therefore likely that the epidermal barrier function may be damaged in PIE.
The stratum corneum is the outer most layer of the epidermis (and thus the skin) and maintains the vital barrier function of the skin by keeping water in the skin and keeping irritants out .
One study investigated oil secretion, stratum corneum lipid levels, transepidermal water loss (TEWL), and stratum corneum hydration in men with mild-to-moderate acne. The study found that acne patients had higher oil secretion, greater TEWL and decreased stratum corneum hydration compared to the acne-free patients. The more severe the acne was the greater the increase in TEWL and decrease in stratum corneum hydration .
In other words, the stratum corneum of acne patients has too much oil and not enough water/hydration. This suggests that the stratum corneum permeability barrier may be damaged in individuals with acne, and that the degree of damage correlates with the severity of acne .
In addition, stratum corneum levels of free sphingosine and total ceramides were significantly reduced in individuals with acne . Evidence also points to an essential fatty acid deficiency, specifically a deficiency of linoleic acid .
However, a different study found that the stratum corneum of individuals with acne had less TEWL, higher water content, and higher skin surface lipid levels than individuals without acne . This study compared individuals with acne to those with rosacea, an inflammatory skin condition characterised by facial erythema and thought to be triggered by damage to the stratum corneum barrier (among a number of other causes).
Note: the proper medical term for what is commonly called ‘acne’ is acne vulgaris. Rosacea (proper medical term – Acne Rosacea) is also a form of acne.
In fact, some forms of rosacea (papulopustular rosacea) are often misdiagnosed as acne due to their similar appearance and symptoms . The persistent redness seen in rosacea is due to repeated blood vessel dilation caused by environmental factors or other triggers . This is in contrast to Post Inflammatory Erythema where the blood vessel dilation is due to the wound-healing process.
Although rosacea and Post Iinflammatory Erythema are completely different conditions and should not be confused with each other, they share some underlying mechanisms that may provide answers on topical treatments for PIE.
Considering that the laser treatment options for Post Inflammatory Erythema (vascular lasers/IPL) are the same as those for treating rosacea as they are targeting the same symptoms (redness/broken capillaries), it is likely that other treatments will overlap as well.
Related Reading: Post-Inflammatory Erythema Treatment: Lasers
In order to further demonstrate this idea, let’s have a look at the main treatment options for rosacea and how they work.
Acne Rosacea Treatment Overview
There are four subtypes of rosacea:
- Erythematotelangiectatic – characterised by flushing and persistent central facial erythema, often with visible broken blood vessels or capillaries.
- Papulopustular rosacea – characterised by papules and pustules that occur centrally on the face. (similar appearance to acne vulgaris)
- Phymatous rosacea – characterised by thickened skin with enlarged pores.
- Ocular rosacea – characterised by watery or bloodshot eyes.
The treatment options for rosacea largely depend on subtype, however, for all subtypes, sun protection, reducing skin irritability, and avoiding triggers for flushing (e.g. hot temperatures, spicy foods, etc.) are recommended .
Topical treatments such as metronidazole and azelaic acid reduce erythema by acting as anti-inflammatories. In addition, azelaic acid also has antibacterial and anti-keratinising effects .
In addition, there are also various topical treatments aimed at improving the stratum corneum barrier function that have demonstrated effectiveness at reducing erythema and inflammatory lesion count in patients with rosacea .
That’s great and all, but what does this mean for PIE? I hear you say…
What Does This Mean for Topical Treatments For Post Inflammatory Erythema?
Well, As Post Inflammatory Erythema is a relatively new term  there isn’t a whole lot of research dedicated to topical treatments to improve the condition. However, there is a lot of research regarding topical treatments to improve erythema and inflammation in rosacea. As the goal of an effective topical treatment for Post Inflammatory Erythema would be one that targets erythema and inflammation, this research seems like a good place to start.
Anecdotally speaking, there have been reports on skincare forums such as r/SkincareAddiction on Reddit and Acne.org of azelaic acid and niacinamide improving the appearance of PIE in some individuals. Both of which have research to back up their effectiveness at reducing erythema in rosacea .
For these reasons, it is possible, and entirely probable, that some topical treatments that work for rosacea will also work for Post Inflammatory Erythema.
From what we have discussed so far, effective topical treatments for Post Inflammatory Erythema could be:
- Those that repair the stratum corneum barrier function by hydrating and reducing TEWL, as well as improving essential fatty acid levels.
- Those that reduce inflammation.
- Those that reduce blood vessel dilation
Topical Treatments for Post Inflammatory Erythema That Repair the Stratum Corneum Barrier Function
Topical treatments aimed at improving the stratum corneum barrier function have demonstrated some ability to reduce erythema .
As mentioned earlier, one of the most important functions of the stratum corneum is the regulation of water in an out of the skin. In vitro and in vivo studies have demonstrated that lipids play a vital role in this water regulation and thus the skin barrier function .
Stratum corneum lipids are rich in sphingolipids (e.g. ceramides), free fatty acids, and cholesterol, which are all required for the epidermal permeability barrier, particularly ceramides .
A number of topical agents can help improve the skins permeability barrier function by increasing the number of lipids in the stratum corneum.
Niacinamide (also known as nicotinamide) is a water-soluble form of Vitamin B3 that can stabilise the skins barrier function, reducing the amount of water loss and improving hydration . Some evidence suggests that this is due to the fact that it increases the levels of ceramides, free fatty acids, and cholesterol in the stratum corneum .
In one study, the application of a moisturiser containing niacinamide twice daily for 4 weeks resulted in an improvement in facial stratum corneum barrier function as measured by reduced TEWL and increased hydration. In addition, facial erythema was reduced in correlation with increased barrier function. This not only provides evidence for niacinamides ability to reduce erythema, but also that facial erythema may be linked to a skin barrier defect .
Another study found improvements in erythema after using a niacinamide formulation twice daily for four weeks. However, only 26% of patients experienced significant improvement, while 50% experienced a moderate improvement .
Related Reading: Skin Benefits of Niacinamide
Vitamin C is the most abundant antioxidant in human skin . It is essential for collagen production, neutralises oxidative stress caused by environmental factors (such as UV radiation, pollution, and smoking), replenishes vitamin e, and reduces pigmentation. It also plays a crucial role in the formation and regulation of lipids and ceramides in the stratum corneum .
One study looked at the effectiveness of vitamin C for reducing facial erythema as well as visible blood vessels and capillaries. Facial erythema decreased by 21% after once-a-day topical application with a vitamin C formulation for 6 weeks . In addition, Vitamin C is good at decreasing the severity and duration of erythema following laser resurfacing . Although, this is more likely due to its anti-inflammatory effect rather than its effect on the stratum corneum barrier function.
However, Vitamin C struggles to penetrate the skin unless the skin pH levels are below 4 and it is in the form of ascorbic acid. Furthermore, Vitamin C needs to be stabilised from oxidisation in order to be effective .
As mentioned earlier, ceramides are essential to maintaining normal stratum corneum barrier function. One of the approaches to repairing skin barrier function is to replace the depleted lipids and improve skin hydration . Research has suggested that stratum corneum ceramides are depleted in individuals with acne , which means it is highly likely that they are also depleted in individuals with Post Inflammatory Erythema.
Indeed, topical ceramides have demonstrated the ability to improve skin barrier function and decrease TEWL, whilst also having an anti-inflammatory effect on the skin .
In one study, a topical cream containing fatty acids, ceramides, and cholesterol significantly improved the skin barrier function, as measured by decreased TEWL and increased skin hydration, as quickly as 30 minutes after application. When the same cream formulation was applied twice daily for 4 weeks, patients experienced significant decreases in erythema. Furthermore, the decrease in erythema was either maintained or decreased further after 8 weeks of application .
Cytokinins are plant hormones that promote skin cell division and have anti-oxidant and anti-inflammatory effects. In addition, cytokinins improve skin barrier function by increasing hydration and reducing TEWL .
In one study, a topical cytokinin (furfuryl tetrahydropyranyladenine) applied twice a day for 12 weeks improved facial erythema in 80% of patients. This also coincided with an improvement in skin barrier function . Both findings were replicated in a follow-up long-term safety study .
Another study found that a similar topical cytokinin improved erythema in as little as two weeks. Furthermore, erythema continued to improve after 4, 8, and 12 weeks . All three of these studies were funded by the same brand, which suggests there could be some element of bias.
However, studies using other topical cytokinin formulations have come to similar conclusions. Topical kinetin (the first discovered cytokinin) at a strength 0f 0.1% in lotion form improved erythema by 31.2% after 12 weeks of daily application .
A further separate study combined kinetin with 4% niacinamide in a topical lotion which was applied to the skin twice a day for 12 weeks. There was a reduction in erythema for those applying the combined lotion but not for those applying niacinamide only. However, erythema was only reduced by 7.3% after 8 weeks and 10% after 12 weeks which, although statistically significant, isn’t a huge reduction .
Other Potential Topical Treatments for Post Inflammatory Erythema That Target The Stratum Corneum Barrier Function:
Lactic Acid: Topical application of lactic acid increases the levels of stratum corneum ceramide levels and reduces TEWL, resulting in a superior lipid barrier . However, as of yet, there is limited research on its ability to improve erythema.
Recommended Products: Dermatix Silicone Gel.
Topical Treatments for Post Inflammatory Erythema that Reduce Inflammation
As discussed earlier, acne is primarily an inflammatory condition and is the precursor to Post Inflammatory Erythema. Inflammation begins when a pore becomes clogged, continues throughout the acne lesions life-cycle, and remains even after the acne lesion has cleared. This remaining inflammation is part of the skins wound-healing response and is accompanied by localised erythema.
As well as reducing inflammation, topical anti-inflammatories can also reduce the associated erythema.
Azelaic acid is a naturally occurring dicarboxylic acid that is often used to treat acne and rosacea due to its anti-inflammatory and antibacterial properties. Its anti-inflammatory effect appears to be as a consequence of its reduction of pro-inflammatory factors and reactive oxygen species .
Another study demonstrated improvement in 68% of patients who applied azelaic acid twice a day for 4 weeks. In these patients, overall erythema was reduced by 69.5% . Azelaic acid has also shown reductions of erythema by 44%-46% in other controlled studies .
Green Tea Serums
Many scientific studies have highlighted the beneficial effects of green tea on a variety of skin conditions. These effects are largely down to the polyphenols (antioxidant molecules) that are present in green tea. The application of green tea polyphenols to the skin has demonstrated some effect at regulating the biochemical pathways involved in inflammatory responses .
The main polyphenol present in green tea is epigallocatechin-3-gallate (EGCG), which seems to be responsible for green teas antioxidant, anti-inflammatory, and anti-redness properties.
A number of research studies have shown that topical ECGC can improve the overall appearance of acne by reducing inflammation. For example, one study found that a topical green tea lotion reduced the number of inflammatory acne lesions when applied twice daily for two weeks . In other similar studies, inflammatory acne lesions were reduced by 89%  and 61%  after topical application of EGCG.
Together, this research suggests that EGCG should be able to continue reducing inflammation after the acne lesions have cleared, thus improving the appearance of Post Inflammatory Erythema. However, there is very little evidence regarding the ability of EGCG or other green tea polyphenols being able to reduce redness.
In one small study, of only 4 patients, EGCG demonstrated the ability to reduce inflammation and blood vessel dilation . Unfortunately, these reductions did not coincide with reductions in facial erythema.
Nevertheless, the ability of EGCG to reduce inflammation and blood vessel dilation suggests that it may be an effective topical treatment for Post Inflammatory Erythema. Although, more research is needed.
Related Reading: Green Tea Serum for Acne
Dual Action Topical Treatments for Post Inflammatory Erythema
Some of the topical treatments for Post Inflammatory Erythema already mentioned can target the condition in more than one way.
- Vitamin C: Improves the appearance of capillary skin, reduces inflammation, promotes wound healing, and improves skin barrier function .
- Niacinamide: Reduces inflammation, promotes wound healing, and improves skin barrier function .
- Cytokinins: Improve skin barrier function and reduce inflammation .
In addition, snail mucin or ‘slime’ is a popular skin treatment that can promote wound healing, hydrate skin, reduce inflammation, and reduce redness. This means that it is likely to be an effective treatment for PIE, although the scientific evidence supporting it is fairly limited. You can read more about it here: The Benefits of Snail Mucin in Skincare.
Other Points To Note:
Some facial cleansers contain what are known as surfactants that are very effective at removing oil and debris from the surface of the skin. This may seem like it makes surfactants essential for acne cleansers. However, some surfactants can interact with stratum corneum proteins, damaging them in the process. This can cause inflammation and erythema as well as worsen any existing inflammation and erythema .
Post Inflammatory Erythema Topical Treatment Overview
You may have heard that “there are no topical treatments for Post Inflammatory Erythema, only prevention and time work”. However, this is only partially true.
Yes, preventing acne in the first place and avoiding picking at active acne lesions will reduce the incidence of PIE. Yes, Post Inflammatory Erythema will go away with time.
BUT there are a number of topical treatments that can help. These topical treatments work by reducing inflammation, reducing blood vessel dilation, promoting wound healing, and improving skin barrier function.
Have you used any of the above-mentioned treatments? Comment below to tell us about your experience of topical treatments for Post Inflammatory Erythema.
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