The initial joy we feel as a pimple recedes is slowly replaced by dismay at the mark it leaves on our skin. The brown stain of a pimples' past in a darker toned or coloured skin can linger for months and sometimes years, often causing just as much distress as they did when they were fresh, red, and angry.
In this article, we will use the term post-inflammatory hyperpigmentation, more commonly known as PIH, as it relates to the brown marks left behind after a pimple has healed. Thankfully, PIH is a well-studied phenomenon. Decades of research have uncovered ways to minimise development of PIH and more rapidly treat it.
What causes post-inflammatory hyperpigmentation in acne?
The first step to solving a problem is understanding it. We know that post-acne hyperpigmentation is caused by the tendency of keratinocytes to produce excessive amounts of melanin (brown pigment) in response to injury and inflammation. If the damage is in the superficial layers of the skin, it’s usually coloured tan or brown. If the damage seeps to a few layers deeper, the melanin is eaten up by immune cells called macrophages, and it appears more grey-blue in colour. This phenomenon is known as the Tyndall effect!
It is important to differentiate between post-inflammatory hyperpigmentation and post-acne scarring. Post-inflammatory hyperpigmentation is not scarring but rather an uneven skin colour without textural change of the skin (bumps or depressions of the skin). Scarring refers more closely to an uneven skin texture. The interventions we discuss here are appropriate for hyperpigmentation, not true post-acne scarring.
The problem of dark spots is more prevalent in coloured skin than white skin. Studies show that those with African, Asian, Pacific Islander, Eastern European and Middle Eastern roots experience hyperpigmentation more often and more severely because their melanin production is higher to begin with, and even more when it’s exacerbated by injury.
Inflammation is a given when it comes to acne, particularly red pimples. Getting a zit, particularly if you are a person of colour, almost guarantees that you’ll have to deal with its aftermath for weeks, months or sometimes even years to come. The bigger and deeper the pimple, the larger and darker its mark will be. But if you pick at it, you’re setting back your skin’s healing time by months or even years.
That is because picking is a surefire way to make an angry pimple off-the-chart furious. We know, it’s all too tempting to just pop that zit, but unless you want an uneven skin tone, you should stop. Binge-watch pimple popping videos if you must satisfy that urge. Just don’t take it out on your skin!
Another way to exacerbate post-acne hyperpigmentation is failing to protect your skin from the sun. Melanin production is directly influenced by sunlight--that’s the principle behind the unhealthy practice of sunbathing to get a tan. The rest of our skin may become a beautiful toasty brown, but the hyperpigmentation will also get a few shades darker along with it.
Dealing with post-inflammatory hyperpigmentation
Let’s say past is past. You’ve had your fair share of pimples, popped a few in desperation, and painfully living through the consequences. But no fear! You can hasten the journey to clearer skin by using products backed up by scientific research.
Use of brightening or ‘depigmenting’ agents
Excessive melanin production is the key issue behind hyperpigmentation, so the best way to address the problem is to incorporate a depigmenting product into your skin care routine.
But note that ingredients that do the job also have the potential to irritate the skin. Before trying anything, make sure to read the instructions carefully and conduct a patch test on a small area of your skin to make sure it doesn’t cause an adverse reaction.
Hydroquinone
Hydroquinone is definitely worthy of mention for those pesky dark spots. It blocks the action of tyrosinase, an enzyme responsible for the final step in the production of melanin. Hydroquinone is well-known to be effective on its own, but many products combine its skin-lightening effect with chemical exfoliators and anti-inflammatories to increase its efficiency and decrease its side effects. While hydroquinone-based products have been known to significantly lessen hyperpigmentation in as early as 4 weeks, they have the potential to cause irritation and allergic reactions. Care should be taken to apply this correctly to avoid lightening the skin around the mark, causing a “halo effect” on post-acne lesions. Using hydroquinone at super-high strengths rarely seen used anymore may cause the development of blue-black marks, a condition called exogenous ochronosis. This seems to occur when hydroquinone is used for long periods of time and in those with darker skin tones. Following label instructions and consulting a medical professional will help ensure you get the most out of this powerful ingredient.
Retinoids
If you’ve done any reading on acne before, you’ve probably heard of retinoids. These Vitamin A derivatives are superstars in the pimple-fighting movement, but studies show that they could achieve the same status in the battle against hyperpigmentation. This is another potent product that must be used carefully in order to prevent side effects like irritation, excessive dryness, and retinoid dermatitis (an eczema-like rash). When used properly, retinoids are great at combating existing acne spots and old acne spots at the same time.
Azelaic acid
It may be strange to use something that comes from a disease-causing fungus, but studies have shown the safety and effectiveness of azelaic acid in addressing both acne and post-acne hyperpigmentation. This ingredient is derived from a fungus that causes pitryiasis versicolor, a condition wherein patches of typically lighter-coloured skin appear. It inhibits enzymes that produce melanin and control populations of rogue melanocytes that produce way more pigment than they should. This is also used to treat other dermatological conditions including rosacea and melasma, where it has been proven safe and effective for people of colour.
Niacinamide
Niacinamide is a form of Vitamin B3 that has multiple benefits to the skin. Not only does it help prevent and reduce inflammation in acne, it can also reduce acne related post-inflammatory hyperpigmentation. It does so by preventing the transfer of pigment-containing molecules from melanocytes (the production house of pigment) to keratinocytes (the cells that make up the majority of the epidermis).
Ascorbic acid
You know it as Vitmain C, but this essential pigment-combating Vitamin is better known to chemists and dermatologists as ascorbic acid. Ascorbic acid used topically can reduce pigmentation in the skin and is commonly used in anti-ageing skin care routines. Not only is it a powerful anti-oxidant, it has an inhibitory effect on the production of melanin and is not uncommonly used by those battling post-acne hyperpigmentation.
Kojic acid
Kojic acid is a pigment reducing agent that is naturally produced through the fermentation process of fungi. Yep! Similar to ascorbic acid, it has potent antioxidant effects but is also used to block the production of melanin through inhibiting the tyrosinase enzyme. This means that kojic acid can lighten those dark spots and minimise skin damage from free radicals, leading to a more even and youthful complexion.
But before you start slathering on kojic acid, make sure to check how it may react to the rest of the members of your skincare regimen. Kojic acid can be a skin irritant if used incorrectly, so follow your doctor’s orders and considering doing a spot test before including it in your routine.
Licorice extract
The root of the licorice plant, Glycyrrhia glabra innera, has long been known to have anti-inflammatory properties that can aid in wound healing and skin repair. The modern version of this herbal medicine is licorice extract. This ingredient is used in the skincare industry for its ability to remove and prevent dark blemishes through tyrosinase inhibition, dispersing clumps of melanin, and also offers very modest protection against solar UVB rays.
Use of chemical peels
Another way to improve post-inflammatory hyperpigmentation is to undergo regular exfoliative treatments. Many of the active ingredients, including glycolic acid, lactic acid and salicylic acid may sound familiar to you because they’re also available as over-the-counter topical products. However, when used in chemical peels, these come in higher concentrations and are therefore performed in clinics.
Chemical peels are able to remove the top layer of the skin (and the excess melanin pigment in it) to reveal the even-toned layers underneath.
However, when potency or strength goes up, you can expect safety to go the opposite direction--hence the tighter regulation on these products. It’s best to have these products administered in a trusted clinic otherwise they can cause irritation and potentially worsen pigmentation.
Use of laser therapy
The fact that melanin can be targeted by specific types of light gave rise to laser therapy for pigmentation. There are certain wavelengths of light that are absorbed preferentially by melanin and can be used to target the cellular components responsible for making and storing melanin. By destroying these at different layers of the skin, it becomes possible to improve hyperpigmentation.
Laser therapy can be just as effective as topical treatments, but it can come at a higher price, so it’s always worthwhile considering your options carefully.
Sun protection
Regardless of what product you buy or treatment you use, there is one thing that is essential when attempting to improve post-inflammatory hyperpigmentation of acne: strict sun protection. While it may not lighten the skin immediately, it certainly stops it from getting darker. It lifts the foot off the accelerator such that the brakes (your treatments) can be more effective.
Short of covering up every centimeter of your skin with clothes or hats, the next best thing to do is using a water-resistant, broad spectrum sunscreen with at least SPF30+ rating, every single day. Whether you’re potting plants in your garden or going for a run in the park, whether it’s an overcast winter’s morning or a hot summer midday, you must protect your skin from the sun.
There are a lot of good products out there, but you won’t get bang for your buck if you don’t use your sunscreen properly. For your face, apply a thick layer of a light-based sunscreen such that it doesn’t clog your pores. Consider applying a second layer after the first layer dries. For your body, you should be able to use a shot glass’ worth everyday. Reapply every few hours, especially if you’re outdoors and sweating. And don’t forget to apply the sunscreen at least 20 minutes before your anticipated exposure to UV.
And what type of sunscreen should you use? Well for the purpose of reducing pigmentation, aim to buy one that is tinted. Why? Tinted sunscreens have iron oxide pigments which not only blocks UV but also blocks visible light which is also a contributor to hyperpigmentation.
Learn cosmetic camouflage techniques
No matter what product you use, expect that it will take weeks to months for hyperpigmentation to improve. Achieving complete skin tone evenness could take years to achieve. So it’s worthwhile learning how to cover up effectively while you wait for those results.
If your post-acne lesions make you feel less confident about yourself, you can use the power of make-up for a temporary solution. Cosmetic camouflage is a term used for make-up techniques to hide hyperpigmentation that results from dermatological conditions like vitiligo, melasma, dyschromia due to sun damage, sun spots and yes, post-acne marks. Studies show that there is significant improvement in the patient’s quality of life when properly educated about how to cover up their dermatoses.
Because cosmetic camouflage is used for medical conditions that cause colour variation of the skin, they use products that go above and beyond your run-of-the mill full coverage foundation. Many of those prescribed by dermatologists incorporate sunscreen and antioxidants, exclude parabens, comedogenic ingredients, fragrances, and other irritating substances that could cause more acne lesions.
Cosmetic camouflage also makes use of the colour-correcting principle. It may be intimidating to use concealers with green or purple pigments at first, but the principle is scientifically sound. You negate the colour of the acne mark with the hue opposite it on the colour wheel.
Acne prevention
If you’ve got acne scars, it’s possible that you still experience acne eruptions now and then, even despite good treatments. As much as we wish we only had to deal with one skin problem at a time, the reality is that we have to juggle acne treatment with hyperpigmentation treatment.
Make sure that your skin regimen is composed of products that do not negate each other’s effects. Doing your research about potential interactions between active ingredients, having a different acne regimen in the morning and night, or spacing out certain products for once-a-week use are a few good ways to help minimise adverse reactions.
Conclusion
Post-acne hyperpigmentation can be just as self-esteem crushing as active acne. We may have been dealt the unfavoured card when it comes to our skin condition, but that does not mean we do not have control over it. Consistent use of science-backed and evidence-based solutions for hyperpigmentation can speed up our journey to clearer skin and remove the barrier of being the best that you can be.
The information presented in this article is for general information and example purposes only, does not contain health advice specific for users and must not be relied on for that purpose. Please see your GP, dermatologist or other health care professional for specific advice.
