Post-Inflammatory Hyperpigmentation After Psoriasis: Dermatologists Explain What Works

By Daniel Okafor

Post-inflammatory hyperpigmentation (PIH), the dark discoloration left after psoriasis plaques resolve, usually fades on its own—but that can take three months, six months, a year or even longer. Four board-certified dermatologists told Allure how patients should treat it, what it costs, and why insurers rarely pay.

"People work really hard; they take medicines to resolve their psoriasis, and the active lesions go away," says Jason Miller, MD, board-certified dermatologist and regional medical director for New Jersey and Long Island at Schweiger Dermatology Group. "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.'"

PIH is not dangerous. Research in psoriasis patients shows it can still damage quality of life. "Hyperpigmentation can be very disfiguring," says Tracy Evans, MD, medical director of Pacific Skin and Cosmetic Dermatology in San Francisco, noting patients have reported depression and lower confidence. "It's a medical issue and should be treated."

What causes it?

Any skin inflammation can trigger hyperpigmentation, not just psoriasis. "Anything that creates inflammation, that brings blood and inflammatory cells to the surface, will cause hyperpigmentation after it resolves," says Shira Y. Wieder, MD, of Montefiore Einstein Advanced Care in New York City.

The mechanism: inflamed skin overproduces melanocytes (the cells that make pigment). "That causes the release of excess melanin into the surrounding areas," Dr. Evans says. "Then that layer remains after the injury."

Psoriasis patients may be especially prone because of two overactive cytokines—immune-signaling proteins the body overproduces in the disease. "This causes the melanocytes to clump together and make more pigment, specifically in psoriasis," says Ava Shamban, MD, a board-certified dermatologist in Los Angeles.

Hyperpigmentation often signals success, not failure. "On the contrary, it's often a sign that the condition is being treated or is under control," Dr. Miller says. The sequence is predictable. "When you treat psoriasis the scales go away first, then the plaque thins," Dr. Wieder says. After the red, purple or brown patch fades, "that's the last thing to resolve." Some patients instead get light spots, called hypopigmentation.

What determines how long it lasts?

All four dermatologists agree on two factors: skin tone and sun exposure. PIH is more stubborn in darker skin tones, and sun worsens dark spots in all skin tones. "The first thing I offer patients is watchful waiting," Dr. Wieder says.

What does treatment actually change for patients?

The first rule: control the psoriasis first. "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.

At-home treatment rests on three categories:

• Brightening ingredients, chiefly hydroquinone. "These are really the first line to try to lighten pigmentation," Dr. Miller says.
• Retinoids, alone or paired with hydroquinone and steroids.
• Sun protection, which prevents worsening though it will not reverse pigment.

Patients should expect to pay out of pocket. Insurers usually classify hyperpigmentation as cosmetic and decline coverage for prescriptions strictly aimed at reversing it.

Expert guidance matters for two reasons. "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." And high-potency hydroquinone carries a real risk: ochronosis, a permanent darkening of the skin.

Dermatologists adjust hydroquinone strength to the plan. "Is this a one-time thing? Is this a recurrent thing? Are you on the more sensitive side?" Dr. Wieder asks. "I'll always have all my patients try it under the chin first just to make sure they tolerate it."

Combination compounded creams can treat psoriasis and PIH at once. "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 notes these ingredients work better combined.

Retinoids carry a caveat. "Tretinoin and even hydroquinone can be irritating," Dr. Wieder says—irritation that could trigger more PIH. She lowers the retinoid dose for sensitive skin but notes that keeping the prescription at 0.025% sometimes secures insurance coverage for the compounds.

Sun discipline shapes scheduling. Dr. Miller times hyperpigmentation treatment for low-sun-exposure periods, such as midwinter, absent sunny vacations. "We don't want people to be exposed to natural sunlight if we can avoid it," he says.

Which in-office treatments help?

The excimer laser treats active psoriasis but not its residual discoloration, Dr. Wieder says. Early, aggressive psoriasis treatment itself reduces the chance of leftover pigment.

"Laser and light energy is helpful for people who have psoriasis in general," Dr. Evans says, noting 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."

Dr. Wieder warns any laser used incorrectly carries burn risk that could worsen psoriasis or provoke new plaques. Dr. Miller urges caution especially in darker skin types: "We try to use the more gentle, mild procedures and work our way up if we need to."

Can patients lower their risk?

There is no guaranteed prevention. Dr. Shamban and Dr. Evans both say aggressive treatment—particularly oral or injectable forms—clears psoriasis faster and cuts PIH odds. Such 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."

For areas showing early inflammation—redness, texture change or itching—sun protection helps. "There's no data to show that will completely stop the process, but it might slow it down," Dr. Miller says, recommending sunscreen or, better, rash guards and sun-protective clothing.

The practical upshot: treat the psoriasis fast and hard, protect skin from the sun, and let a board-certified dermatologist—experienced with psoriasis patients—manage any pigment that remains.