Post-Inflammatory Hyperpigmentation and Acne

The Best Ways to Treat Dark Acne Marks

Post-inflammatory hyperpigmentation from acne on the back.
Photo: Arada Photography / iStock

Post-inflammatory hyperpigmentation, those dark marks or discolored spots left behind after a pimple heals, can be even more aggravating and distressing than pimples themselves. Why do those dark spots develop, and what can you do to get rid of them?

What Is Post-Inflammatory Hyperpigmentation?

Post-inflammatory hyperpigmentation, or PIH, is the medical term used to describe discoloration of the skin that follows an inflammatory wound.

It is the skin's natural response to inflammation.

PIH usually looks like a flat area of discoloration on the skin (these flat, discolored areas are also called macules.) It can range in color from pink to red, purple, brown or black, depending on your skin tone and depth of the discoloration.

PIH develops when a wound or irritation, like a scrape, rash, or pimple, causes your skin to become inflamed. As the skin heals, it produces too much melanin. Melanin is the protein in the skin that gives the skin its color. It's the excess melanin that darkens and discolors the skin. This discoloration remains even after the wound has completely healed.

It can develop in all skin types, but it tends to be more severe and longer lasting for people with medium to dark complexions. PIH affects both men and women equally.

Acne Is a Cause

Post-inflammatory hyperpigmentation is very common. Most people with acne have some degree of post-inflammatory hyperpigmentation.

And it's not just the big blemishes that cause these spots. Hyperpigmentation can follow even relatively minor pimples and papules.

However, the more inflamed a breakout, the larger and darker the PIH spot tends to be. Picking or popping a pimple increases the chance of developing post-inflammatory hyperpigmentation, simply because you're increasing inflammation.

Acne Scars vs. Post-inflammatory Hyperpigmentation

Would you be relieved to learn that post-inflammatory hyperpigmentation is not true scarring? It is often called "pseudo scarring" because although it leaves a mark on the skin for a period of time, it does not actually damage the follicle.

True acne scars occur when there is either a loss of tissue, causing a pitted or depressed area, or an overgrowth of tissue leaving a raised scar.

Post-inflammatory hyperpigmentation, on the other hand, is flat. It's not pitted or raised, simply darker than the surrounding skin. This discoloration can range in color from pink to red, purple, brown, or black.

Fading Over Time

The good news? PIH can fade away over time, even without treatment. But time is the operative word here. It can take three to 24 months for PIH to fully fade, although in some cases it may take longer.

The length of time it takes for PIH to fade depends on how dark the spot is compared to the surrounding skin. The bigger the contrast between the macule and your natural skin tone, the longer it will take to fade.

Post-inflammatory hyperpigmentation doesn't always fade away on its own. In some cases, it's more or less permanent.

There are treatments out there that will help, if not completely erase dark marks, at least lighten them considerably.

Treatment can also help speed up fade time, if you're not keen to wait for spots to lighten naturally.

Treatment Options

Over-the-counter products can be helpful in fading more subtle marks. For deeper marks, or those that have been around for a long time, a prescription cream is a better choice. Your dermatologist has a bevy of products that can do the trick.

Another good point to remember—if you beat acne you'll also stop developing hyperpigmentation. This is an important step in clearing up PIH, and another step with which your dermatologist can help.

Whatever treatment option you choose, understand that improvement will take time.

Alpha Hydroxy Acids (AHAs)

Alpha hydroxy acids, especially glycolic acid, are a good starting point for treatment. Alpha hydroxy acids (AHAs) help speed up the skin's natural exfoliation process, which can help improve the look of post-inflammatory hyperpigmentation.

You can find these ingredients in a plethora of over-the-counter "brightening" treatments. Leave-on treatments like lotions, creams, and gels will give you better results than wash-off products like cleansers.

Other OTC ingredients that can be helpful in fading hyperpigmentation are N-acetyl glucosamine, niacinamide, and vitamins A and C.

Stronger AHA treatments are available with a prescription. AHAs are often used as anti-aging treatments too, and will leave your skin super soft and smooth.

Hydroquinone

Hydroquinone is a widely used treatment for post inflammatory hyperpigmentation. It is available over-the-counter at 1 percent to 2 percent strength, and in 3 percent to 4 percen prescription creams. Hydroquinone works by blocking the enzyme responsible for melanin production, thereby lightening the skin.

Hydroquinone creams often contain additional lightening ingredients, such as kojic acid, glycolic acid, tretinoin and other retinoids, or vitamin C. These combination creams can give you better results than using hydroquinone alone.

Hydroquinone creams should be carefully applied to darkened areas only, to prevent the unwanted lightening of your natural skin color. Hydroquinone may cause skin irritation for some people so it's worth talking to your doctor before beginning hydroquinone treatment.

Topical Retinoids

Topical retinoids are often prescribed to treat acne. Retinoids help clear acne by speeding up cell turnover rates. This rapid exfoliation can also help fade post-inflammatory hyperpigmentation.

Retinoid creams include Retin-A (tretinoin) and Retin-A Micro, Tazorac (tazarotene), and Differin (adapalene). The fact that they lessen post inflammatory hyperpigmentation as they treat acne breakouts is an added benefit.

With the exception of Differin, these medications are available by prescription only. Obvious results may not be apparent for several weeks to several months after beginning treatment.

Be on the lookout for excessive dryness, redness, and irritation. This can trigger post-inflammatory hyperpigmentation on its own.

Azelaic Acid

Azelaic acid is another medication used to treat acne as well as post-inflammatory hyperpigmentation. It works by decreasing inflammation and speeding up cell turnover rates. Azelaic acid is sometimes used in conjunction with glycolic acid or tretinoin.

Some studies have shown azelaic acid to be as effective as hydroquinone at treating hyperpigmentation. It is a good alternative for those who may be unable to use hydroquinone.

Azelaic acid is available by prescription only. As always, monitor your skin for redness and irritation and let your doctor know right away if you experience these side effects.

Salon and In-Office Treatments

More persistent cases of post inflammatory hyperpigmentation can be treated professionally at skin spas, medi-spas, or your dermatologist's office. Procedural treatments include various chemical peels and/ormicrodermabrasion.

But just one treatment isn't enough to fade hyperpigmentation. You'll likely need a series of treatments spaced a week or so apart (depending on the procedure you're having done).

Your doctor can help determine which of these treatments, if any, would be most effective for you.

Treatment Tips

Before you jump in and start treating your post-inflammatory hyperpigmentation marks, use these tips to set the stage for the best results possible.

  • Your acne should be under control or at least being treated. Otherwise, each new pimple could cause another dark spot and you would never get ahead of the curve (and never see the clear, even skin tone you're looking for).

    Over-the-counter acne products are effective for treating mild acne. More stubborn or severe breakouts need to be treated with prescription acne medications if you want to see real improvement.
  • Use sunscreen every day. The sun may darken the discolorations and increase fading time. Plus, many post-inflammatory hyperpigmentation treatments (and many acne treatments, too) can make your skin more sensitive to the sun.

    If you're worried that sunscreen could make your breakouts worse, don't be. There are many sunscreens available that are appropriate for breakout-prone skin.
  • Monitor your skin for irritation. Although they are helping you clear your skin, acne treatments and post-inflammatory hyperpigmentation treatments alike also have the potential for causing irritation.

    Unfortunately, irritated skin could lead to even more dark spots and uneven skin tone. If post inflammatory hyperpigmentation is a problem for you, let your dermatologist know if your skin becomes irritated from your acne treatments.

A Word From Verywell

When you're ready to begin treatment, you have plenty of options.

Be prepared to be patient. Post-inflammatory hyperpigmentation takes a long time to fade, no matter which treatment option you choose. Think in terms of months rather than weeks. Steady and consistent treatment is your friend.

Remember, this isn't a comprehensive list. Other treatments may be available. Your dermatologist can help guide you to the right treatment for your skin.

Sources:

Mohamed Ali BM, Gheida SF, El Mahdy NA, Sadek SN. "Evaluation of Salicylic Acid Peeling in Comparison with Topical Tretinoin in the Treatment of Postinflammatory Hyperpigmentation." Journal of Cosmetic Dermatology. 2017 Mar;16(1):52-60.

Sarkar R, Parmar NV, Kapoor S. "Treatment of Postinflammatory Hyperpigmentation With a Combination of Glycolic Acid Peels and a Topical Regimen in Dark-Skinned Patients: A Comparative Study." Dermatologic Surgery. 2017 Apr; 43(4):566-573.

Shokeen D. "Postinflammatory Hyperpigmentation in Patients with Skin of Color." Cutis. 2016 Jan;97(1):E9-E11.

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