The first thing we check before treating pigmented spots is whether the brown spots we are seeing are truly the same type of lesion.

 

That is because what we commonly call “dark spots” can include many different lesions, such as solar lentigines, freckles, melasma, post-inflammatory hyperpigmentation, and sometimes even seborrheic keratosis, all of which have different characteristics.

From the outside, they may simply look like “a few brown spots.” But in reality, some are relatively superficial with clear borders, some are spread broadly and hazily, and some may actually become darker if treated too aggressively.

 

That is why pigmented spot removal should begin with accurately identifying what type of lesion it is.

 

Simply put, treatment is less about “removing it strongly” and more about designing how to separate and treat each type of pigmentation.

 

Then why does this difference matter?

 

Among lesions commonly called dark spots, solar lentigines and some freckles often have relatively clear borders and are mainly located in the epidermal layer.

 

Melasma, on the other hand, often appears as broad and blurred pigmentation, and it is frequently associated not only with pigment but also with vascular response, inflammation, UV exposure, and skin barrier problems.

So even on the same face, some lesions may be better suited for spot treatment, while others may require treatment that adjusts the broader background pigmentation, such as toning.

 

If we treat every brown lesion on the face in the same way without understanding this difference, one of two things may happen: the overall skin tone may become slightly brighter, but the visible spots remain; or the spots may fade somewhat, but the skin becomes more sensitive and uneven.

 

A 2020 study by Kim et al., published in Annals of Dermatology, helps show this difference more clearly.

 

This was a split-face study comparing a 532 nm picosecond Nd:YAG laser with a 532 nm Q-switched Nd:YAG laser on the same patient’s face. In other words, to reduce differences caused by individual skin type, one side of the same face was treated with a picosecond laser, while the other side was treated with a Q-switched laser.

What does Fig. 3 show?

 

The attached Fig. 3 shows before-and-after changes in one patient.

 

In the upper row, A shows the 532 nm picosecond laser treatment, with the left image taken before treatment and the right image taken 12 weeks after treatment.

 

In the lower row, B shows the 532 nm Q-switched neodymium:yttrium-aluminum-garnet laser treatment, also with the left image before treatment and the right image 12 weeks after treatment.

 

When looking at the image, both treatments appear to reduce the pigmented spots over time. However, if we look more closely, the brown spots seem to be more clearly improved on side A, the picosecond laser-treated side.

 

The paper also states that “solar lentigines on the 532 nm PS laser treatment side are more clearly removed without post-inflammatory hyperpigmentation.”

 

Simply put, the picosecond laser side showed cleaner removal of the spots, with relatively less post-treatment brown discoloration.

Then what does Fig. 4 show?

 

The attached Fig. 4 is an even more intuitive image. It compares one patient’s face divided into two halves: the left half-face treated by 532 nm picosecond laser and the right half-face treated by 532 nm Q-switched neodymium:yttrium-aluminum-garnet laser.

 

The upper image, A, shows the face before treatment, and the lower image, B, shows the face 12 weeks after treatment. When looking at the image, the two sides do not appear completely identical after treatment.

 

The paper explains that post-inflammatory hyperpigmentation was less visible on the left side, which was treated with the picosecond laser, compared with the right side.

This means that removing the spot itself is important, but preventing the skin from becoming brown and uneven afterward is also a very important part of the treatment outcome.

 

Especially in Asian skin, inflammation after laser treatment can sometimes make post-inflammatory hyperpigmentation, or PIH, more concerning than the original spot.

 

That is why pigmented spot removal should not be approached as simply removing everything strongly in one session. The pigment should be selectively broken down while minimizing damage to the surrounding skin.

 

In this study, the picosecond laser side showed better clinical improvement, and the rate of PIH was also reported to be lower. However, this does not mean that picosecond lasers are always the only correct answer.

 

The reason is that the study mainly focused on solar lentigines, which are relatively well-defined pigmented spots.

 

In real clinical practice, melasma, freckles, redness, and sensitive skin barrier issues are often mixed together on the same face.

 

That is why, when I explain pigmented spot treatment, I often use the expression “separating the spots” rather than simply “removing the spots.”

 

Distinct lesions may need spot treatment. Broad background pigmentation may need toning. If redness or skin sensitivity is significant, restoring the skin condition may need to come before laser treatment.

 

In the end, even if the pigmentation looks similar, one person may need spot treatment first, while another may need toning and barrier care first.

 

To summarize, pigmented spot removal is not simply a matter of “which laser is stronger.”

We first need to evaluate what type of pigmentation is present on the face, whether the borders are clear or diffuse, whether the pigment is superficial or deep, and how high the risk of post-treatment pigmentation may be.

 

As shown in the study by Kim et al., even within the same 532 nm laser category, the picosecond laser showed somewhat more favorable results than the Q-switched Nd:YAG laser in terms of spot removal and PIH.

 

However, real skin is often more complex than a single study image.

 

What ultimately matters is accurately separating the pigmentation on your face and designing treatment in the right order.

Pigmented spot removal is not simply a treatment that removes spots as if erasing dots. It is better understood as a treatment that distinguishes and organizes different types of pigmentation within the face :)

 

This was Director Won Dae-han.

 

Thank you for reading.

 

Source:
Kim JY, Yang JH, Hur K, Choi YJ, Kim WS. A Split-Face, Single-Blinded, Randomized Controlled Comparison of 532 nm Picosecond Neodymium-Doped Yttrium Aluminum Garnet Laser versus 532 nm Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser in the Treatment of Solar Lentigines. Annals of Dermatology. 2020;32(1):8-13. DOI: 10.5021/ad.2020.32.1.8.

 

※ This article is intended to provide general medical information. Actual suitability for pigmented spot removal, treatment method, number of sessions, and treatment interval may vary depending on lesion type, skin type, presence of melasma, and degree of UV exposure. An accurate diagnosis and treatment plan should be determined through consultation.