Pigment coming back after a laser is the most common worry in Asian skin. In May 2025 an Australian dermatology journal published a review collecting what can prevent it. Sunscreen was the only measure confirmed to reduce occurrence itself.
Post-inflammatory hyperpigmentation is the brown mark left behind where inflammation has passed through the skin. It appears where acne has healed and where a laser has been used. The researchers collected studies on preventing it following the PRISMA procedure.
PRISMA requires stating the search terms and everything included and excluded, so that someone else can repeat the same search.
Fourteen studies and 369 cases were included. Mean age was 38, 72% were women, and every participant was of Asian background.
| Skin type | Share |
|---|---|
| Fitzpatrick III | 42% |
| Fitzpatrick IV | 54% |
| Fitzpatrick V | 4% |
The Fitzpatrick scale sorts skin into six types by how it burns and how it tans. Higher numbers mean darker skin and a greater tendency to retain pigment after inflammation. Koreans usually fall into types III and IV, which is where 96% of the cases in this review sit.
More than 95% of the pigmentation collected here was triggered by a laser procedure. Lasers outweighed acne and other inflammation by a wide margin.
By preventive measure the findings divided as follows.
| Measure | Finding |
|---|---|
| Sunscreen (alone or combined) | Consistently reduced occurrence itself |
| Topical steroid | Reduced severity, not incidence |
| Oral tranexamic acid | Reduced severity, not incidence |
| Cooling device during treatment | Pigmentation was more common |
What reduced occurrence itself was sunscreen. Steroids and tranexamic acid lightened marks that had already appeared. The two do different jobs.
The unexpected finding came from cooling. Devices that blow cold air during laser treatment are used to reduce pain and thermal injury. Pigmentation was more common where they were used.
Why was not established here. The included studies differed too much in their conditions to separate out cooling intensity or duration.
Reading it as an instruction not to cool goes too far. It is an association that appeared once 14 studies were pooled, not a demonstrated cause. What the data does not support is the reassurance that cooling was used so pigmentation is not a concern.
The 369 cases are spread over 14 studies, an average of 26 each. That is not enough to rank products or say which sunscreen is better.
It is also not an incidence study. It is the distribution of which procedures preceded 369 cases that had already occurred.
The directly usable part of this review is the sunscreen. It was the one measure confirmed to reduce occurrence itself.
Applying it only after the procedure is not enough. The included studies looked at outcomes under sunscreen use before and after treatment. There are a few days when crusting makes application difficult, and covering with a hat or a mask stands in during that window.
Pigment-suppressing medication is sometimes prescribed in advance. On this review those drugs lighten what appears rather than prevent it from appearing. A prescription is not a reason to be less careful about sun protection.
What this review shows is that prevention and lightening are different jobs. Sunscreen reduced occurrence itself; steroids and tranexamic acid lightened what had already appeared.
If a laser is planned, sunscreen starts before the procedure and gives way to covering up during the days of crusting. With more than 95% of 369 cases following a laser, that order matters more.
The claim that cooling removes the pigmentation concern is not supported here. Treatment settings are something to discuss at the appointment.
This review does not calculate incidence. It shows that more than 95% of the 369 cases collected followed a laser procedure.
Sunscreen was the measure confirmed to reduce occurrence itself. Which product and how often to apply it was not settled in this review.
In this review oral tranexamic acid reduced the severity of pigmentation but not how often it occurred. It is a prescription medication and needs monitoring, so it is not a decision to make alone.
Across the 14 studies, pigmentation was more common where a cooling device was used. The reason was not established and the data cannot show cause. Treatment settings are something to discuss at the appointment.
