The road to clear skin can be long and winding for someone with psoriasis. And even when itchy rashes and uncomfortable plaques finally resolve, another concern can arise: post-inflammatory hyperpigmentation (PIH). Triggered by inflammation, PIH leaves patches of skin darker than the surrounding area.

This type of skin discoloration isn’t dangerous, but it can be a frustrating stage of the psoriasis healing process. “People work really hard; they take medicines to resolve their psoriasis, and the active lesions go away,” says board-certified dermatologist Jason Miller, MD. “And instead of looking at clear skin, they’re looking at this reminder that ‘Hey, I had this condition and now it’s left this stain in my skin.’”

Research done specifically in psoriasis patients has shown that it can negatively affect their self-reported quality of life. “Hyperpigmentation can be very disfiguring,” says Tracy Evans, MD, a board-certified dermatologist, noting that patients with the skin condition have reported depression and lower confidence. “It’s a medical issue and should be treated.”

Fortunately, there are several highly effective and safe ways to improve PIH. Here’s what doctors recommend to treat the condition, plus what causes it and how you can lower the risk of it happening in the first place.

Meet the experts:

• Tracy Evans, MD, is a board-certified dermatologist, dermatologic surgeon, and medical director of Pacific Skin and Cosmetic Dermatology in San Francisco.
• Jason Miller, MD, is a board-certified dermatologist and the regional medical director for New Jersey and Long Island for Schweiger Dermatology Group.
• Ava Shamban, MD, is a board-certified dermatologist in Los Angeles.
• Shira Y. Wieder, MD, is a board-certified dermatologist at Montefiore Einstein Advanced Care in New York City.

What causes hyperpigmentation in people with psoriasis?

Hyperpigmentation is not exclusive to people with psoriasis. “Any inflammatory process in the skin can lead to hyperpigmentation,” says Shira Y. Wieder, MD, a board-certified dermatologist. “Anything that creates inflammation, that brings blood and inflammatory cells to the surface, will cause hyperpigmentation after it resolves.” This is because of the overproduction of melanocytes, the cells that produce skin pigmentation. “That causes the release of excess melanin into the surrounding areas,” Dr. Evans says. “Then that layer remains after the injury.”

Although post-inflammatory hyperpigmentation can happen to anyone, there has been some research into why people with psoriasis may be more prone to it. The issue appears to come down to two cytokines that are overactive in patients with psoriasis. Cytokines help your immune system mount a defense when germs or other harmful substances enter your body. With psoriasis, the body makes too many of these two cytokines. “This causes the melanocytes to clump together and make more pigment, specifically in psoriasis,” says board-certified dermatologist Ava Shamban, MD.

Something to note: Hyperpigmentation isn’t a sign that anything’s gone wrong. “On the contrary, it’s often a sign that the condition is being treated or is under control,” Dr. Miller says. These dark spots (or, in some patients, light spots called hypopigmentation) don’t happen to everyone, but when they do, they typically appear after psoriasis is being managed or resolving.

“When you treat psoriasis the scales go away first, then the plaque thins,” Dr. Wieder says. “It becomes flush with the skin, but it’s still often red or violaceous, depending on the patient’s original skin color.” After the red, purple, or brown patch fades, what’s left is the post-inflammatory hyperpigmentation. “That’s the last thing to resolve,” she says.

How long does post-inflammatory hyperpigmentation last?

Even if you don’t do anything to treat post-inflammatory hyperpigmentation, it usually goes away on its own. “The first thing I offer patients is watchful waiting,” Dr. Wieder says. But that can take a while: three months, six months, a year, or even longer.

All the dermatologists interviewed for this story agree that how long hyperpigmentation lasts depends primarily on the patient’s skin tone and how much time they spend in the sun. Hyperpigmentation can be more stubborn in patients with darker skin tones, and the sun can worsen dark spots in all skin tones.

How to treat hyperpigmentation at home

First and foremost, dermatologists agree you should treat your psoriasis before attempting to treat any hyperpigmentation that arises as a side effect. “The most important thing is to make sure the active psoriasis is under control because that’s where new areas of pigment are going to come from,” Dr. Miller says.

Once you have the disease well controlled, you can look into the three primary categories of at-home treatments: brightening ingredients, retinoids, and sun protection. Your dermatologist may prescribe compounded creams or recommend products you can buy over the counter at the drugstore. Unfortunately, this likely all has to be paid for out of pocket—even if you use a product prescribed by your doctor. Hyperpigmentation is usually considered a cosmetic issue, so insurance isn’t likely to cover prescriptions that are strictly for reversing it.

Brightening treatments

Dermatologists will often rely on hydroquinone-based brighteners to treat hyperpigmentation in psoriasis patients. “These are really the first line to try to lighten pigmentation,” Dr. Miller says.

You’ll want to team up with your dermatologist to find an effective treatment. “There are a lot of brightening treatments on the market that just don’t work,” Dr. Evans says. “People spend a lot of money on treatments that are really useless.” On the flip side, Dr. Wieder says you don’t want to accidentally use a very high-potency hydroquinone, which can cause side effects like ochronosis, a permanent darkening of the skin.

Your doctor can also help determine the hydroquinone strength that will work best for you. “We tweak the prescribed percentage depending on how long we plan to use it for,” Dr. Wieder says. “Is this a one-time thing? Is this a recurrent thing? Are you on the more sensitive side? And I’ll always have all my patients try it under the chin first just to make sure they tolerate it.”

Retinoids

Hydroquinone is often paired with other topical ingredients, mainly retinoids and steroids, which can also help treat psoriasis. But sometimes they’ll use a retinoid alone, “which has been shown to help with the post-inflammatory hyperpigmentation,” Dr. Wieder says.

If your dermatologist thinks multiple ingredients may help, they might prescribe a compounded cream with the ingredients combined for you. This reduces the need to apply multiple products, which can feel overwhelming or cumbersome, and ensures you’re getting the exact percentage of each ingredient your skin needs. “A brightening agent that has the steroid combined with the hydroquinone and the retinoid is actually helpful for both the psoriasis and the hyperpigmentation,” Dr. Evans says. Dr. Miller agrees, noting that these ingredients tend to work better when combined.

Again, you’ll want a dermatologist to guide you through this treatment. Retinoids such as tretinoin can help, but “tretinoin and even hydroquinone can be irritating,” which could lead to more post-inflammatory hyperpigmentation, Dr. Wieder says. “I’ll lower the retinoid amount in people who have sensitive skin, but if you keep the retinoid prescription at 0.025%, sometimes certain insurances do cover those compounds.”

Sun protection

While sunscreen won’t reverse hyperpigmentation, proper sun protection is crucial to treating it. “Hyperpigmentation is pigmented skin,” Dr. Evans says. “All pigmented skin likes to get more pigmented with the sun, so keeping out of sunlight is helpful to prevent it from getting worse.”

Dr. Miller even likes to schedule his patients’ hyperpigmentation treatment during a time when they’re at a lower risk for sun exposure—like the middle of winter, provided there are no sunny vacations on the horizon. “We don’t want people to be exposed to natural sunlight if we can avoid it,” Dr. Miller says.

In-office treatments that can help with hyperpigmentation

Although sunlight can worsen hyperpigmentation, derms recommend certain light-based in-office treatments—for both psoriasis and any residual dark patches—if topical treatments haven’t been fully effective. “The laser that can help psoriasis is called an excimer laser,” Dr. Wieder says. “That laser does not help the discoloration that a plaque of psoriasis leaves, but truly treats the psoriasis only.” But, as previously mentioned, treating psoriasis early and aggressively can reduce your chance of developing residual hyperpigmentation.

“Laser and light energy is helpful for people who have psoriasis in general,” Dr. Evans says, noting that she typically uses a Fraxel or pico laser. “You have to be careful. You don’t want to damage the skin—you want to stimulate it.” It will ultimately be up to your provider to guide you on the treatment that’s best for your skin, which is why it’s crucial to see a board-certified dermatologist who has plenty of experience in treating psoriasis patients—and let them know if you’ve had any recent sun exposure or other trauma to the skin that could affect your outcome, Dr. Evans says. Dr. Wieder warns that any laser used incorrectly comes with a burn risk, which could actually worsen the psoriasis or cause more plaques to pop up.

Dr. Miller, who, like Dr Wieder, uses excimer lasers to treat active psoriasis, also emphasizes the need for care when using lasers. “We have to be a little bit cautious with light-based therapies, especially with patients with darker skin types, to make sure we don’t make these processes worse,” he says. “We try to use the more gentle, mild procedures and work our way up if we need to.”

How to lower your risk of post-inflammatory hyperpigmentation

There’s no surefire way to prevent post-inflammatory hyperpigmentation, but treating psoriasis early and practicing proper sun protection can help reduce your risk. Both Dr. Shamban and Dr. Evans say that using aggressive treatment —particularly oral or injectable forms—that can get rid of the psoriasis more quickly helps lower your chances of developing PIH. Those treatments “kind of melt away the psoriasis before there’s a lot of residual inflammation,” Dr. Evans explains. “If you can limit the inflammation, then you can, hopefully, limit the hyperpigmentation.”

As noted earlier, wearing sunscreen is also a biggie when it comes to preventing hyperpigmentation. Dr. Miller notes that areas showing signs of inflammation (like redness, texture change, or itching) have the potential to turn into hyperpigmentation once the psoriasis is otherwise treated. “If you start seeing an area that looks like it might pigment, getting started with some good sun protection—or, even better, rash guards or sun-protective clothing—is really going to be helpful,” he says. “There’s no data to show that will completely stop the process, but it might slow it down.”

Read more about psoriasis:

• The Little-Known Impact Psoriasis Can Have on Your Nails
• 10 Beauty Products and Treatments That Can Trigger a Psoriasis Flare
• Are Tanning Beds Really a Psoriasis Treatment? Here’s What Dermatologists Have to Say

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