Sun spots and PIH may look similar at first glance, but they behave very differently beneath the surface.
If you’ve ever looked in the mirror and thought, “Why are these dark spots not fading no matter what I use?”
Well, you’re not alone. I see this all the time in the clinic.
A patient comes in, tells me they’ve been diligently applying brightening creams for months… sometimes even trying a laser elsewhere… but the spots are still there. Or worse, they’ve become darker or more widespread.
Often, the issue isn’t effort. It’s that we’re treating the wrong type of pigmentation [1].
Not all dark spots are the same, even if they look similar at first glance. Two of the most common types I diagnose are sun spots and post-inflammatory hyperpigmentation (PIH), and confusing one for the other can lead to frustrating results.
But, understanding the difference is where things start to change.
Sun spots, or solar lentigines/lentigos, are essentially the skin’s memory of sun exposure over time.
They tend to have a very distinct look:
A common scenario I hear:
“I only have one or two spots on my cheek, but they’ve been there for years. They don’t change, no matter what I do.”
That’s very typical of sun spots.
They usually show up on areas that get the most sun (cheeks, temples) and once they form, they tend to stay put [2] unless treated properly.
PIH often appears as patchy, uneven pigmentation following acne, irritation or skin inflammation.
PIH is a different story altogether [3].
It happens after the skin has gone through some form of irritation or inflammation [4], with acne being the most common trigger.
Other causes include:
Visually, PIH looks quite different:
If you’ve ever had an acne breakout that left behind “marks” long after the pimples are gone, that’s PIH. That lingering pigmentation is PIH.
The good news is, unlike sun spots, PIH can fade over time. But only if the skin is allowed to heal without ongoing irritation.
At a glance, both just look like “dark spots”.
But when we take a closer look, the differences become clearer:
| Differences | Sun spots | PIH |
| Shape | Well-defined | More diffused |
| Cause | Sun exposure | Triggering events eg post acne outbreak or injuries |
| Behaviour | Persistent | Potentially fading |
These differences would directly help us come to a diagnosis of sun spots or PIH.
The same laser doesn’t always work the same way for different types of pigmentation.
This is where things often go wrong. Many patients assume one treatment works for all pigmentation. But in reality, responses can vary quite a bit.
Both sun spots and PIH can improve with:
These help control pigment production and prevent worsening.
But here’s the difference I usually explain:
For more noticeable, severe or resistant pigmentation, lasers can be very effective [6], but only when used correctly. This is where accurate diagnosis really matters.
Sun spots and PIH require very different laser approaches:
I’ve seen cases where patients come in after a laser done elsewhere and say: “The spots didn’t improve… and now I feel like there are even more.”
Sometimes, the issue isn’t the laser itself. It’s that the settings weren’t suited to the type of pigmentation.
In fact, using the wrong laser approach can lead to:
That’s why assessment before treatment is so important.
One of the more encouraging aspects of PIH is that it can fade naturally [7].
But there’s a catch!
It only happens if the skin isn’t repeatedly triggered by preceding event egs:
If those factors are controlled, you may notice gradual lightening over several months.
That said, many patients still choose to treat it to speed things up for better and faster results.
Getting the diagnosis right often makes the biggest difference in results.
If there’s one thing I emphasise to patients, it’s this:
Treating pigmentation without knowing what it is often leads to unnecessary trial and error.
Even though sun spots and PIH both involve excess pigment, they behave very differently, especially when it comes to lasers.
When we identify the type correctly, we can:
Rather than treating all dark spots the same, it helps to think of pigmentation as a group of different concerns.
A more effective treatment plan usually involves:
When these pieces come together, results tend to be more consistent and far less frustrating.
The right diagnosis often makes treatment feel much more straightforward.
In a climate like Singapore, where both sun exposure and acne-related pigmentation are common, it’s easy for these conditions to overlap.
If you’re dealing with pigmentation spots that don’t seem to respond, or you’re not quite sure what you’re looking at, it may be worth having it properly assessed.
Seeing the right skincare doctor can make a very big difference in results.
If you’d like a clearer understanding of your skin issues or pigmentations and what it actually needs to be treated well, you may schedule an appointment with our dedicated team at ONE FACE Clinic.
Post-inflammatory hyperpigmentation (PIH) can take anywhere from a few weeks to several months to gradually lighten, depending on the types of triggering events, depth of pigmentation and individual skin response. Superficial marks tend to fade faster, while deeper pigmentation may persist longer. Continued sun exposure or repeated skin irritation can slow down this process.
PIH is more common in individuals with darker skin tones or those who are prone to stronger inflammatory responses in the skin. When the skin is irritated, it produces excess melanin as part of the healing process. The more intense the inflammation, the higher the likelihood of noticeable PIH developing afterwards.
Yes, picking or squeezing pimples increases inflammation and skin injury, which significantly raises the risk of developing PIH. This is one of the most common reasons acne marks become more noticeable and longer-lasting.
Yes, sun spots can gradually darken with ongoing sun exposure. Ultraviolet (UV) radiation stimulates melanocytes (pigment-producing cells), which can increase the intensity of existing spots and lead to the formation of new ones if sun protection is not consistent.
Mild pigmentation may respond to over-the-counter brightening products. However, medical treatments such as hydroquinone cream or combination therapies with lasers are typically much more effective when guided by the right skincare doctor. Incorrect use of products may sometimes worsen pigmentation or irritate the skin further.
Often sun spots and PIH can respond well to topical medical creams eg hydroquinone.
If lasers are needed, sun spots and PIH may also respond well under the experienced hands.
However if the wrong laser settings are used, the desired results may not occur, and worse still, post laser darkening side effects may also occur.
This is why proper assessment with the right doctor is so important before starting any laser-based treatment.
Pigmentation can recur, especially if the underlying triggers are not addressed. For example, continued sun exposure may cause sun spots to reappear, while ongoing acne or skin irritation can lead to new PIH. Maintenance care, including sun protection and proper skincare, plays an important role in preventing recurrence.
Preventive care is often just as important as treatment. This includes:
Consistent habits can help reduce the likelihood of pigmentation beco
If pigmentation persists despite consistent skincare, becomes darker over time or affects larger areas of the face, it may be worth seeking a professional assessment. Early evaluation helps ensure the correct type of pigmentation is identified and managed accordingly, which can then substantially improve treatment outcomes.
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