Post-Inflammatory Hyperpigmentation and Acne

Post-inflammatory hyperpigmentation (PIH) is those dark marks or spots left behind after a pimple heals. Often, they can be even more aggravating and distressing than pimples themselves.

PIH is discoloration of the skin that remains after a wound heals. It is the skin's natural response to inflammation.

This article explains why those dark spots develop and what you can do to get rid of them.

PIH Symptoms

PIH usually looks like a flat area of discoloration on the skin. It can appear white, pink, red, purple, brown, or black, depending on your skin tone and the depth of the discoloration.

PIH can develop in all skin types. However, it tends to be more severe and longer-lasting for people with medium to dark complexions. PIH affects all sexes.

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Causes

PIH develops when a wound or irritation, like a scrape, rash, or pimple, causes the skin to become inflamed. As the skin heals, it produces too much melanin (the protein that gives the skin its color).

Most people with acne have some degree of PIH. And it's not just the big blemishes that cause these spots—hyperpigmentation can follow even relatively minor pimples and blemishes.

That said, the more inflamed a breakout, the larger and darker the PIH spot tends to be. In addition, picking or popping a pimple increases the chance of developing PIH because it increases inflammation.

Other causes of PIH include:

• Sunburn
• Chemical peels
• Dermabrasion
• Laser resurfacing

Acne Scars vs. PIH

You may be relieved to learn that PIH is not true scarring. In fact, people often call it "pseudo scarring" because although it leaves a mark on the skin for a while, it does not 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. PIH, on the other hand, is flat. It's not pitted or raised, simply darker than the surrounding skin.

Fading Over Time

The good news is that 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 disappear entirely, or even longer in some cases.

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

Some treatments will help. Some may not wholly erase dark marks, but they might at least lighten them considerably. Therapy can also help speed up fade time if you're not keen to wait for spots to lighten naturally.

Treatment Options

Over-the-counter (OTC) products can help fade more subtle marks. However, for deeper marks or those that have been around for a long time, a prescription cream might be a better choice. Your dermatologist has a lot of products that can do the trick.

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 PIH.

You can find these ingredients in many OTC "brightening" treatments. In addition, leave-on treatments like lotions, creams, and gels will give you better results than wash-off products like cleansers.

Other OTC ingredients that can help fade hyperpigmentation include:

• N-acetyl glucosamine
• Niacinamide
• Vitamins A and C

Hydroquinone

Hydroquinone is a widely used treatment for PIH. It's available over the counter in 1%-2% strengths and 3%-4% prescription creams. Hydroquinone works by blocking the enzyme responsible for melanin production, thereby lightening the skin.

These creams often contain additional lightening ingredients, which can give you better results than using hydroquinone alone. Ingredients combined with hydroquinone include:

• Kojic acid (a chemical made from fungi)
• Glycolic acid
• Tretinoin and other retinoids
• Vitamin C

Topical Retinoids

Dermatologists often prescribe topical retinoids to treat acne. That's because retinoids help clear acne by speeding up cell turnover rates. This rapid exfoliation can also help fade PIH.

Retinoid creams include:

• Retin-A (tretinoin)
• Retin-A Micro
• Tazorac (tazarotene)
• Differin (adapalene)

Except for Differin, these medications are available by prescription only. Like with other treatments, it may take several weeks to several months to see noticeable results.

When using these treatments, be on the lookout for excessive dryness, redness, and irritation, as this can trigger PIH on its own.

Azelaic Acid

Azelaic acid is another medication used to treat acne and PIH. It works by decreasing inflammation and speeding up cell turnover rates. People sometimes use azelaic acid along with glycolic acid or tretinoin.

Some studies have shown azelaic acid to be as effective as hydroquinone at treating hyperpigmentation. Therefore, it is a good alternative for those who can't use hydroquinone.

In-Office Treatments

More persistent cases of PIH can be treated professionally at your dermatologist's office. Treatments include:

• Chemical peels
• Lasers
• Microneedling
• Microdermabrasion

Just one treatment isn't enough to fade hyperpigmentation. You'll likely need a series of treatments spaced two to four weeks apart (depending on the procedure you're having done). Your healthcare provider can help determine which of these treatments, if any, would be most effective for you.

How To Get the Best Results

To get the best results possible, you'll want to be sure to set the stage. Keeping a few things in mind can help prepare your skin for whichever treatment you choose.

Control Your Acne

Before treatment, your acne should be under control. 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. However, you may need to treat more stubborn or severe breakouts with prescription acne medications if you want to see real improvement.

Use Sunscreen

Use sunscreen every day. The sun may darken the discolorations and make them fade more slowly. Plus, many PIH 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 for breakout-prone skin.

Monitor Your Skin

Monitor your skin for irritation. Although treatments are helping you clear your skin, acne treatments and PIH treatments alike also have the potential for irritation.

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

Summary

PIH is dark spots left on the skin after a pimple heals. It doesn't damage the skin, so it doesn't cause pits or raised scars on the skin.

PIH usually heals over time without treatment, but it can take up to a couple of years. Some spots may never fade. Treatments include OTC creams, prescription medications, and in-office procedures.

To get the best results from treatment, be sure your acne is under control and use sunscreen. During treatment, carefully watch your skin for irritation.

A Word From Verywell

When you're ready to begin treatment, you have plenty of options. Be prepared to be patient. PIH 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, and your healthcare provider can help guide you to the proper treatment for your skin.