Ever notice dark marks that linger long after a breakout or rash has healed? That discoloration is called post-inflammatory hyperpigmentation, or PIH. According to dermatologist and SLMD Skincare founder Sandra Lee, MD (aka Dr. Pimple Popper), PIH is extremely common. And with the right approach, it’s manageable.

Understanding why PIH forms, how it looks on different skin tones, and what actually helps it fade can make the process feel far less frustrating.

Fast facts: post-inflammatory hyperpigmentation

• Post-inflammatory hyperpigmentation is caused by inflammation
• PIH appears as darkened spots or patches after skin trauma heals
• It is more common and longer-lasting in deeper skin tones
• Sun exposure can worsen and prolong post-inflammatory hyperpigmentation

What causes post-inflammatory hyperpigmentation?

Post-inflammatory hyperpigmentation develops when the skin responds to inflammation by producing excess melanin. Acne is the most common trigger, but PIH can also follow insect bites, rashes, burns, or cosmetic procedures.

When inflammation reaches deeper layers of the skin, melanocytes become overstimulated. As the skin heals, that excess pigment remains behind as a dark mark — even though the original injury is gone.

What does PIH look like?

Post-inflammatory hyperpigmentation can look different depending on skin tone and the depth of inflammation.

On lighter skin tones, PIH may appear tan, light brown, or even slightly red-brown. On deeper skin tones, it often shows up as dark brown, gray, or black patches that can be more noticeable and slower to fade.

Unlike scars, PIH does not change the texture of the skin. The surface feels smooth, but the color remains uneven.

How PIH is different from acne scars and PIE

PIH is often confused with other marks left behind after acne clears. Knowing the difference helps set realistic expectations.

• Post-inflammatory hyperpigmentation (PIH): Flat dark spots caused by excess pigment after inflammation
• Post-inflammatory erythema (PIE): Red or pink marks caused by dilated blood vessels, more common in lighter skin tones
• Acne scars: Permanent textural changes such as indentations or raised areas

How long post-inflammatory hyperpigmentation lasts

PIH can take weeks, months, or even longer to fade, depending on how deep the inflammation was and how well the skin is protected during healing.

Sun exposure, picking, and ongoing breakouts can all make dark spots linger longer. Consistent skincare and patience are essential — rushing the process with aggressive treatments can actually worsen discoloration.

How dermatologists treat post-inflammatory hyperpigmentation

Treating PIH works best when prevention and correction happen together.

PIH improves most reliably when inflammation is addressed first. “The goal is to calm the skin first,” explains Dr. Lee. “When inflammation stays under control, dark spots have a better chance to fade naturally.”

Preventing new dark spots

Controlling inflammation is the first step. Treating breakouts early and avoiding picking helps prevent new pigment from forming. Daily sun protection (try SLMD Daily Moisturizer with SPF 15) is also critical, since UV exposure stimulates melanin production and can darken existing marks.

Ingredients that support fading

• Chemical exfoliants to support skin turnover. Try: SLMD AHA/BHA Swipes
• Retinoids to encourage renewal and even tone. Try: SLMD Retinol Resurfacing Serum
• Antioxidants to support overall skin clarity. Try: SLMD Vitamin C Serum

At this stage, it’s important to introduce products slowly and avoid irritation, which can trigger new pigmentation.

Dr. Pimple Popper tip: “If you’re treating PIH, avoid stacking too many brightening products at once. Over-irritating the skin can restart inflammation and actually make dark spots last longer.”

In-office options

For stubborn PIH, dermatologic treatments such as chemical peels or laser therapy may help speed fading. These should always be performed or supervised by a professional, especially for deeper skin tones, where the risk of worsening pigmentation is higher.

FAQ: post-inflammatory hyperpigmentation

Q: Does post-inflammatory hyperpigmentation go away on its own?

A: Post-inflammatory hyperpigmentation often fades gradually over time, especially when the skin is protected from sun exposure and further irritation.

Q: Can acne treatments make PIH worse?

A: Harsh or irritating treatments can trigger more inflammation, which may worsen PIH. Gentle, consistent care is key.

Q: Is PIH the same as melasma?

A: PIH is triggered by inflammation, while melasma is hormonally driven and often symmetrical. They are treated differently.

Q: Why does PIH last longer on darker skin tones?

A: Deeper skin tones naturally produce more melanin, which can make pigment changes more pronounced and slower to fade.