- Why measure melasma treatment success?
- What is the Melasma Area and Severity Index (MASI)?
- What is the newer, updated, Melasma Severity Index (MSI)?
- Successful melasma treatments are possible, but buyers should beware of what that means
Lately, there’s been a lot of online buzz in the beauty industry about treating hyperpigmentation and melasma. Not many people know this, but when skin care companies talk about “success” with their melasma treatments, they are expected to be using a recognized measurement scale, known as the Melasma Area and Severity Index (MASI).
However, more recently, scientists have proposed alternate scales, most notable of which is the Melasma Severity Index (MSI). But, no matter what scale is used, measurement is important when determining the effectiveness of melasma treatments.
We should also note that there are other scaling systems for this condition, such as the Melasma Severity Scale (MSS) and the Melasma Quality of Life scale (MELASQOL). We won’t get into those here, since they are not often used to validate modern melasma studies.
Why measure melasma treatment success?
Melasma is a condition that is not consistent – not between patients, and not even within a single patient’s lifetime. It can come and go (such as with pregnancy, or by taking certain medications). It can be darker or lighter in some patients, and more or less spread out across the face and body. In fact, some people group all hyperpigmentation disorders as being ‘melasma,’ even though they are technically different.
To know whether someone’s melasma is being reduced with treatment, there needs to be a starting point at which to define their level of hyperpigmentation (that is, the patchy darkening of skin).
What can we learn from measuring melasma, and why should melasma patients care?
By measuring melasma severity, we can be realistic about how well hyperpigmentation treatments can potentially work. We can also predefine what “success” means when it comes to treating this problem.
You see, when we talk about a successful reduction in melasma, in reality, that can mean a slight difference in colour (i.e. depigmenting the skin). Some patients may not consider this “successful.” However, the slight colour change is still one that is statistically significant. Scientists will certainly call it “successful.”
Patients often expect a total clear up of melasma, but this is not always possible. However, some progress is better than none. Reducing hyperpigmentation can still mean a big quality of life change for some patients.
The other reason to define “success” is that there are many products on the market claiming to “clear up melasma,” or so to speak. Consumers should know what companies mean by their “melasma success rates,” if they can quote them. Otherwise, claims can be misleading.
What is the Melasma Area and Severity Index (MASI)?
The original MASI score (proposed in 1994) has been helpful in diagnosing and treating patients with melasma.
When scoring melasma for severity, the MASI calls for a calculation whereby the following features are rated:
a = Area of involvement (rated from 0 to 6) → *note this is a larger scale!*
d = darkness, or intensity (rated from 0 to 4).
h = Homogeneity, or uniformity (rated from 0 to 4).
The rating for “area of involvement” is measured as follows:
0 – area is not affected at all.
1 – less than 10% of the area is affected.
2 – between 10% and 29% of the area is affected.
3 – between 30% and 49% of the area is affected.
4 – between 50% and 69% of the area is affected.
5 – between 70% and 89% of the area is affected.
6 – between 90% and 100% of the area is affected.
The rating for “darkness” is measured as follows:
0 – darkness is not present at all.
1 – darkness is “slight.”
2 – darkness is “mild.”
3 – darkness is “marked.”
4 – darkness is “severe.”
The rating for “homogeneity” is measured as follows:
0 – homogeneity is “minimal.”
1 – homogeneity is “slight.”
2 – homogeneity is “marked.”
3 – homogeneity is “maximum.”
The above features are rated on the following areas of the face:
f = forehead (considered to be 30% of the face).
mr = right malar (cheek) region (considered to be 30% of the face).
ml = left malar (cheek) region (considered to be 30% of the face).
c = chin (considered to be 10% of the face).
Putting it all together, the formula for measuring melasma severity with the MASI looks like this:
MASI = 0.3 × A (forehead) × (D + H) (forehead) + 0.3 × A (left malar) × (D + H) (left malar) + 0.3 × A (right malar) × (D + H) (right malar) + 0.1 × A (chin) × (D + H) (chin)
The highest score one can receive with this formula is 48. In other words, melasma severity is rated between 0 to 48, and the higher the rating, the more severe a person’s melasma is.
The problem with the MASI system for determining successful melasma treatments
The MASI system is appreciated for its highly accurate measurements (especially in comparison to the over-simplified MSS system, which is just a 0 – 3 categorical rating). However, it has some flaws. Some say it is not practical for ‘real life’ scenarios.
A major issue with the MASI method is that the “area of involvement” is given a higher score than other features of the disease. This is because it was originally based on the Psoriasis Area and Severity Index (PASI), which is a different condition altogether.
When measuring psoriasis on the whole body, a 10% or 20% difference in area size can mean a lot. It can be a major factor in determining how advanced a person’s condition is.
But that’s not the case with melasma.
Firstly, this disease is usually only measured on the face, which is a smaller area size than the whole body.
Secondly, the intensity (i.e. darkness) of spotty pigmentation can sometimes be worse (i.e. more intense) than its surface area or size.
The fact that the “area of involvement” can receive a higher score with the MASI means that,
A person with a really severe pigmentation involving a smaller area of face gets a lower MASI score as compared with a person who has a really mild pigmentation involving a relatively larger part of the face. This does not correlate with the clinical judgment of the burden of the disease.”–https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4763693/
Basically, scientists found that when this severity scale is applied to hyperpigmentation disorders it doesn’t fully address what patients want treatment for.
This can also be problematic when undergoing treatment because, with melasma, the darker the pigmentation, the more advanced, yet careful, a treatment regimen needs to be. Size is not the main determinant for a path of treatment.
In actual practice, most doctors who treat hyperpigmentation know this. They focus on intensity, rather than size, to determine a course of treatment for melasma patients. Then, when pigmentation intensity is reduced, treatment is considered effective.
But the MASI score doesn’t fully reflect that success, because the calculation is focused more on size.
The mathematical formula itself is also very cumbersome and confusing, making it hard to use.
The areas that MASI measures are also not reflective of how melasma presents itself (more on that below).
What is the newer, updated, Melasma Severity Index (MSI)?
Due to the errors that can come from the older scoring system, researchers proposed a modified MASI (called an mMASI), around 2011. It basically took out the “homogeneity” factor, because it was just confusing people and didn’t change calculations that much.
But eventually, by 2016, researchers proposed the Melasma Severity Index (MSI), which was determined to be more accurate, and more useful. You can read that study, here.
With the MSI, the following features are rated:
a = Area of involvement (rated from 0 to 4) → *note this is NOT a larger scale!*.
p = Pigmentation intensity (rated from 0 to 4).
The ratings are correlated to severity as follows:
0 – no hyperpigmentation at all.
1 – 10% severity or size of the area. This is considered “barely visible pigmentation.”
2 – between 11% to 30% severity or size of the area (or, more than 1/10 but less than 1/3). This is considered “mild pigmentation.”
3 – between 31% to 60% severity or size of the area (or, more than 1/3 but less than 2/3). This is considered “moderate pigmentation.”
4 – between 61% to 100% severity or size of the area (or, anything more than 2/3). This is considered “severe pigmentation.”
Then, “area of involvement” and “pigmentation intensity” are individually measured on the:
l = Left face
r = Right face
n = Nose
Note: the nose is measured separately because it is affected very differently by melasma. It also responds differently to treatment. The MASI assumed the “nose” was part of the “cheek,” but this was not practical, since it was always harder to treat.
Putting it all together, the formula for measuring melasma severity with the MSI looks like this:
MSI = 0.4 (a × p2) r + 0.4 (a × p2) l + 0.2 (a × p2) n
Or, if it is obvious that the pigmentation intensity is the same across the face, it can be scored as a whole (instead of by its parts). In these cases, doctors can use the following formula:
MSI = a × p2
The outcome of this newer scoring system means that, even when a patient shows small improvement from melasma treatments, whether in size or intensity, it can be justified as a viable solution to this disease.
For patients with hyperpigmentation on their face, being able to go from a stage 3, to a stage 1 on the MSI could mean a major quality of life improvement. This is important because, apart from distress, melasma is an otherwise asymptomatic disease (though, it can be related to other root issues). Any amount of skin tone correction can be considered a relief.
So, why assume that a potential treatment doesn’t work, just because it doesn’t reduce size, even if it does reduce intensity?
There ARE melasma treatments that work, and they should be defined as “successful” if they reduce discolouration even a little.
Successful melasma treatments are possible, but buyers should beware of what that means
As we’ve seen above, measuring melasma correctly:
- Is important to determine how effective treatments can be, and how effective they have been in certain patients.
- Can set expectations straight for patients who are expecting a total clear up of melasma when a product quotes high treatment success rates.
- Can help researchers and doctors determine an appropriate treatment path for different ‘grades’ of melasma, if needed (subjective judgement per each individual is always advised, however).
- Validates the distressing aspect of melasma for those who have severely darkened hyperpigmentation, and not just for those who have large, but lighter areas of hyperpigmentation.
Moreover, by using effective, yet accurate melasma measurements, such as the MSI, researchers can work towards better and better treatments for this disease.