Post-inflammatory hyperpigmentation (PIH) is treatable with a combination of sun protection, topical brightening agents, and patience. These dark spots left behind after acne, eczema, burns, or other skin injuries can take months to years to fully resolve, and without active treatment, complete clearance is unlikely. The good news: several effective options exist at every price point, from daily sunscreen to prescription creams and professional procedures.
Why PIH Happens and Why It Lingers
When your skin is injured or inflamed, the healing process triggers excess melanin production. That melanin gets deposited in the upper layers of skin (or sometimes deeper in the dermis), leaving behind flat, discolored patches that range from pink to red, brown, or nearly black depending on your skin tone. The darker your natural complexion, the more melanin your skin produces in response to inflammation, and the longer those marks tend to stick around.
A systematic review of people with darker skin tones found that PIH had been present for an average of 21 months before patients sought treatment. Among those who received no treatment at all, not a single person achieved complete clearance. About two-thirds saw partial fading, while a third saw no improvement whatsoever. That makes a strong case for active treatment rather than simply waiting it out.
Sunscreen Is the Foundation
UV light and visible light stimulate the same pigment-producing cells responsible for PIH in the first place. Skipping sunscreen while using brightening treatments is like mopping the floor with the faucet running. In a study of 89 African American and Hispanic participants, daily sunscreen use alone lightened existing dark spots in 81% of people and reduced the total number of spots in 59% within just eight weeks. Participants using SPF 60 saw greater improvement than those using SPF 30.
A broad-spectrum sunscreen with at least SPF 30 is the minimum. If your skin tone is medium to deep, look for formulas that also block visible light, since darker skin responds strongly to UVA and visible wavelengths. Tinted mineral sunscreens containing iron oxides are one practical option for visible light protection. Apply every morning and reapply every two hours when you’re outdoors.
Topical Treatments That Fade Dark Spots
Retinoids
Retinoids (tretinoin, adapalene, tazarotene) work by speeding up the rate at which your skin sheds old cells and replaces them with new ones. This accelerated turnover physically moves pigment-loaded cells to the surface faster, where they’re shed. Retinoids also block the transfer of pigment granules from melanin-producing cells to surrounding skin cells, addressing the problem at its source. Clinical data shows that tretinoin, adapalene, and tazarotene all produce significant partial improvement in PIH after 12 weeks of consistent use.
Adapalene 0.1% is available over the counter (sold as Differin), making it the most accessible starting point. Tretinoin requires a prescription but comes in higher strengths. Start slowly, applying every other night, since retinoids themselves can cause irritation that triggers new PIH if you overdo it.
Hydroquinone
Hydroquinone has been the most widely used skin-lightening ingredient for nearly 50 years. It works by inhibiting the enzyme that produces melanin. Over-the-counter products contain 2% concentrations, while prescription formulas go up to 4%. The key safety rule: limit continuous use to about 3 to 5 months, then take a break. Prolonged, unmonitored use at high concentrations can cause a paradoxical darkening called ochronosis. Cycling on and off under guidance keeps this risk very low.
Azelaic Acid
Azelaic acid at 15% to 20% concentrations targets overactive pigment cells while leaving normally pigmented skin alone. It’s gentler than hydroquinone, safe for long-term use, and available by prescription (with lower concentrations sold over the counter). It also has anti-inflammatory and antibacterial properties, making it a good choice if your PIH stems from acne that’s still active.
Tranexamic Acid
Tranexamic acid is a newer addition to the PIH toolkit. It works by blocking a chain reaction in the skin: UV light normally activates an enzyme called plasmin, which then signals pigment cells to ramp up production. Tranexamic acid interrupts that signal. Topical formulas in the 2% to 5% range applied twice daily have shown visible lightening by 4 to 8 weeks, with efficacy comparable to azelaic acid. It’s well tolerated and available in many over-the-counter serums without a prescription.
Combination Formulas
For stubborn PIH, dermatologists sometimes prescribe a triple combination known as the Kligman formula: 5% hydroquinone, 0.1% tretinoin, and a mild topical steroid blended together. The hydroquinone suppresses new pigment, the retinoid accelerates cell turnover, and the steroid reduces inflammation (which also reduces irritation from the other two ingredients). This is a prescription-only approach typically used for a defined period rather than indefinitely.
Professional Procedures
When topical treatments alone aren’t enough after several months, in-office procedures can help. Chemical peels using glycolic acid, salicylic acid, or lactic acid remove the outermost pigmented skin layers in a controlled way. These are typically done in a series of sessions spaced two to four weeks apart. Superficial peels carry less risk of rebound darkening than deeper peels, which matters significantly for medium to dark skin tones.
Laser treatments are an option but require careful selection. Certain lasers, particularly those with shorter wavelengths or aggressive settings, can actually worsen PIH in darker skin. Q-switched lasers and picosecond lasers at conservative settings are generally considered safer choices. Any procedure that creates inflammation in the skin carries some risk of triggering new hyperpigmentation, so the experience of the provider with your skin type matters as much as the technology itself.
Special Considerations for Darker Skin
PIH is more common, more visible, and more persistent in people with medium to deep skin tones. The same treatments that work for lighter skin also work here, but the margin for error is narrower. Irritation from too-strong products, aggressive chemical peels, or poorly calibrated laser settings can create new inflammation and new dark spots, putting you back at square one.
Start with lower concentrations of active ingredients and increase gradually. Retinoids in particular should be introduced slowly. Hydroquinone above 2% deserves professional oversight. And sun protection is non-negotiable, even for very dark skin, since UV and visible light still stimulate melanocytes regardless of your baseline complexion.
Realistic Timeline for Results
PIH that sits in the upper layers of skin (epidermal PIH, which tends to look brown) responds faster to treatment than PIH that has settled into deeper skin layers (dermal PIH, which often appears grayish or blue-gray). Epidermal PIH typically shows meaningful improvement within 3 to 6 months of consistent treatment. Dermal PIH can take a year or longer, and in some cases, complete resolution may not be possible.
Most topical treatments need at least 12 weeks before you can fairly judge whether they’re working. Retinoids hit that benchmark reliably in clinical studies. Tranexamic acid can show early results by 4 to 8 weeks. Without any treatment, the average time to partial fading was about 68 days in one analysis, but remember: none of those untreated patients achieved full clearance.
The most effective approach combines multiple strategies at once: daily broad-spectrum sunscreen, one or two targeted topical treatments, and avoidance of whatever caused the inflammation in the first place (treating active acne, for example, prevents new spots from forming while you work on fading old ones). Consistency over months is what ultimately produces results.