When consulting patients about melasma and pigmented spot treatment, one of the most common things I hear is this.

 

“Isn’t pico toning enough?”

 

From the outside, they may all look like brown spots, blotchy pigmentation, or dull skin tone, so it is easy to feel that they are all similar dark pigment issues.

 

But when we actually examine the skin, these pigment lesions are not all the same.

 

Some may be melasma, some may be solar lentigines, some may be freckles,
and some may be deeper pigmentation such as acquired bilateral nevus of Ota-like macules, or ABNOM.

 

The problem starts here. Inside the broad term “melasma and dark spots,”
there may be completely different pigment disorders mixed together.

 

If all of them are treated with the same laser at the same intensity, the pigmentation may not improve, and in some cases, it may even become darker.

 

That is why the most important part of melasma and pigmented spot treatment is not the laser device or the procedure itself, but diagnosis.

 

Today, I would like to explain why melasma and pigmented spots need to be approached differently, how pico lasers and nanosecond lasers differ, and what kind of pigment changes were observed in a study that included actual before-and-after photos :)

Melasma and pigmented spots may look similar in location and shape, but their causes can be different.

 

Melasma often appears broadly and hazily on both cheekbones, cheeks, forehead, or around the mouth.

 

Rather than looking like a sharply defined spot, it often looks like a brown mist spread over the skin.

 

On the other hand, solar lentigines and freckles usually have relatively clearer borders.

 

They may look like small dots or brown patches, and they tend to appear more often in areas that receive a lot of sun exposure.

 

ABNOM, or acquired bilateral nevus of Ota-like macules, may look similar to melasma on the surface, but the pigment is often located in a deeper layer of the skin.

 

That is why simply repeating toning as if it were melasma may not lead to much response, and in some cases, the treatment direction needs to be different.

 

Simply put, all pigmentation may look “brown,” but its location inside the skin can be different.

 

Treatment changes completely depending on whether the pigment is in the epidermis, closer to the dermis, or accompanied by vascular reaction and inflammation.

If you look at the image above, pigment located superficially in the epidermis and pigment located deeper near the dermis are different from the beginning.

 

Superficial pigment may respond relatively quickly to spot treatment.

 

On the other hand, deeper pigment may require repeated treatment and a longer course rather than disappearing after one or two sessions.

 

Melasma is different again.

 

Melasma is not simply a problem of having too much melanin.

 

It is often influenced by multiple factors, including the skin barrier, vascular reaction, inflammation, hormones, and UV exposure.

 

So if melasma is treated too aggressively, as if burning off a solar lentigo in one session, post-inflammatory hyperpigmentation, or PIH, may occur, or the melasma itself may become more sensitive.

 

That is why in melasma and pigmented spot treatment, what matters more than “removing it strongly” is “separating the lesions accurately and treating them accordingly.”

 

I often explain it this way to patients.

 

Broad, background pigmentation should be managed with toning, while distinct spot-like lesions should be treated separately with spot treatment.

 

Even on one face, some areas may need toning, while others may need spot treatment.

When talking about pigmentation lasers, you have probably heard terms like pico toning and nano toning.

 

The key difference here is how long the laser stays in the skin.

 

Nanosecond lasers use short pulses measured in nanoseconds, while picosecond lasers use even shorter pulses measured in picoseconds.

 

To explain this simply, if a nanosecond laser breaks pigment more through a heat-based impact, a picosecond laser is closer to breaking pigment into smaller particles with a shockwave-like effect in a much shorter time.

 

Of course, the actual mechanism cannot be divided this simply.

 

But for patients, it may be easier to understand that nanosecond lasers rely more on a photothermal effect, meaning heat-related action, while picosecond lasers emphasize a photomechanical effect, meaning mechanical shock.

 

That is why pico lasers are often described as breaking pigment particles into smaller fragments while reducing unnecessary thermal damage to surrounding tissue.

 

However, this is where we need to be careful.

 

Just because it is a pico laser does not mean every case of melasma or pigmented spots can be finished in one session.

 

What matters more than whether the laser is pico or nano is which pigment is being treated, with what wavelength, at what energy level and interval, and at which depth.

There is also a study that includes actual before-and-after photos.

 

In a study by Kim et al., 20 Korean patients were treated using a split-face design.

 

One side of the face was treated with a 532 nm picosecond laser, while the other side was treated with a 532 nm Q-switched Nd:YAG laser for solar lentigines.

 

A split-face study means that different lasers are compared on opposite sides of the same person’s face.

 

This method is meaningful in comparative studies because it helps reduce differences caused by individual skin type.

 

The study compared photos taken before treatment and 12 weeks after treatment.

 

Figures 3 and 4 include actual clinical before-and-after photos.

 

In the before-and-after images above, brown solar lentigines are visible before treatment, and the pigmentation appears lighter after 12 weeks.

 

In particular, the description of Figure 3 explains that the solar lentigines were more clearly removed on the 532 nm picosecond laser-treated side, and post-inflammatory hyperpigmentation was not observed.

The graph above compares the results of the 532 nm picosecond laser and the 532 nm Q-switched Nd:YAG laser.

 

In this study, the QIS score evaluated 12 weeks after treatment was 2.95 on average for the picosecond laser side and 1.8 on average for the Q-switched Nd:YAG side.

 

QIS is, simply put, a score that evaluates how much the pigmentation has lightened.

 

A higher number means greater improvement.

 

Another important point is post-inflammatory hyperpigmentation.

 

The study reported that PIH was observed in 5% of the picosecond laser-treated areas and 30% of the Q-switched Nd:YAG-treated areas.

 

This part is very important.

 

In pigmentation treatment, removing pigment is important, but preventing the skin from becoming darker after treatment is often even more important.

 

Especially in Asian skin, if PIH occurs after laser treatment, it may remain a concern longer than the original pigmented spot.

 

So in melasma and pigmented spot treatment, what matters is not “how strongly the laser is applied,” but “how safely the skin response is created and how well the recovery process is managed.”

Pigmented spots with clear borders, such as solar lentigines or freckles, may temporarily become darker or form a thin crust after spot treatment.

 

This can happen as the pigment reacts and moves toward the surface.

 

But melasma is different.

 

Melasma is not a lesion that should be treated with the goal of creating a strong crusting reaction.

 

If the skin becomes overly sensitive, or if redness, dryness, or stinging lasts too long, the pigmentation may become darker again.

 

That is why melasma treatment is rarely completed with laser alone.

 

UV protection, brightening ingredients, skin barrier recovery, and, if necessary, vascular laser or inflammation control should be considered together.

This is where treatment design changes.

 

Broad melasma should be approached with low-energy toning, gradually lowering the pigment tone without overstimulating the skin.

 

On the other hand, visible solar lentigines or freckles should be selectively targeted with spot treatment.

 

If both are present on the same face, repeating toning alone may leave the spot-like lesions unchanged.

 

On the other hand, if spot treatment is performed too aggressively, broad melasma may become more sensitive.

 

That is why it is difficult to immediately answer the question, “How many sessions do I need for melasma and pigmented spots?”

 

The number of sessions and intervals differ depending on whether melasma is the main issue,
whether solar lentigines are dominant, whether there are many freckles, whether ABNOM is mixed in,
or whether redness and vascular reaction are also present.

 

In actual clinical practice, visual examination alone is often not enough.

 

Even if brown spots look similar on the surface, imaging devices can help us more objectively check whether epidermal pigment is dominant, whether deeper pigment is mixed in, or whether redness is present together.

 

Through this process, the treatment sequence becomes clearer.

 

We can decide whether to repeat pico toning only, combine spot treatment, consider vascular laser treatment, or first stabilize home care and the skin barrier.

 

This is exactly why diagnosis is so important in melasma and pigmented spot treatment.

 

Even with a good device, if the diagnosis is wrong, the treatment direction can become wrong.

 

On the other hand, if the lesions are properly separated, even the same laser can be planned more safely and effectively.

 

To summarize, successful melasma and pigmented spot treatment starts with identifying which lesions are mixed together.

 

Toning, spot treatment, vascular treatment, barrier care, and UV protection should all be designed according to the skin condition.

 

In the end, pigmentation treatment is not simply about choosing one good laser.

 

The difference comes from accurately reading the pigment map of your face :)

 

This was Director Won Dae-han.

 

Thank you for reading.

 

Source:
Kim JY, Choi M, Nam CH, Kim YJ, Chung JH, Kim WS. Treatment of Solar Lentigines with 532 nm Picosecond Laser: A Prospective, Randomized, Split-Face, Controlled Trial. 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 melasma and pigmented spot treatment, laser type, number of sessions, and treatment interval may vary depending on each individual’s skin condition, pigment depth, and lesion type. An accurate diagnosis and treatment plan should be determined through consultation.