2023-06-12 09:15:55
In recent years, improved understanding of the pathophysiology has led to more treatment options for melasma. Particularly in patients with treatment-resistant, recurrent melasma, it is important to use a treatment that affects several areas, emphasizes dermatologist Dr. David Njoo (David Njoo Skin & Laser Clinics).
The treatment of melasma, and in particular the understanding of its pathophysiology, has changed in recent decades. For example, melasma is a more heterogeneous disease than previously thought, says Njoo. “At the turn of the century, we still considered melasma to be a pure pigment disorder. Or as overactivity of the melanocytes. At the time, we mainly focused on the hormonal cause of melasma, partly because this plays a major role in a pregnancy mask. And for many women, it really is a pregnancy mask and the discoloration will go away on its own after pregnancy. Then there is only a temporary increase in the stimulation of the melanocytes by estrogens and progesterone. At the time, we also mainly handled pigment production. The excessive allspice production was often treated with the classic Kligman formula, with hydroquinone, retinoids and hydrocortisone. But we now know that after stopping the bleaching cream, the condition often returns. Therein lies the challenge. Why does it come back, and how do we keep the result constant?”
In recent years it has become clear that melasma should not be seen as a pure pigment disorder, but as a sun damage problem, says Njoo. “Sun damage not only manifests itself as premalignant skin cancer, but also through early aging of the skin, the skin becoming drier and blood vessels expanding. And in some cases also with pigment spots.”
Because of the major role of the sun, melasma is also relatively common in people with colored skin, says Njoo. “Especially with Asian skin, but also with people from South America. This is, as it were, based on a ‘behavioral problem’. People with a more tinted skin are often not brought up with the idea that it is important to protect themselves well against the sun. And of course the sun shines much more in those regions than in Western European countries, so there is much more exposure to sunlight.”
Long-term sun damage
In addition, it has become clear that for melasma to occur, the skin must have been exposed to the sun for a long time. Njoo: “The UV damage in the skin is the result of years of exposure. It’s not like you come home with melasma after being burned 1 time. The prolonged exposure leads to various forms of skin damage such as defects in the basement membrane. The membrane separating the epidermis from the dermis shows leakage. That explains why the pigment is also present in the deeper skin layers. Where we used to think that melasma was purely an epidermal problem, it is now increasingly apparent that we also have to look in the dermis.”
In the dermis, there are all kinds of signs of sun damage, such as solar elastosis, telangiectasias, but also an increase in mast cells. Njoo: “The latter is not related to an allergic reaction, but indicates senescence of the skin cells. The skin gets old. In fact, there are 2 problems: on the one hand an overproduction of melanin and on the other hand defects in the basement membrane, causing the pigment to leak down into the dermis, as it were. And if the pigment gets there, it can be absorbed by macrophages and that gives the same effect as a tattoo. Long-standing, treatment-resistant melasma often involves melanin that has been taken up by macrophages.”
Bleaching cream insufficient
“Given all these effects, you can imagine that a bleaching cream alone is not always sufficiently effective to remove the discoloration,” continues Njoo. “Whitening creams with tyrosinase inhibitors mainly have an effect on the upper layers of the skin, while the tyrosinase enzyme is also present in the dermis. But a cream has no effect on that, unless you administer the tyrosinase inhibitors systemically or inject them into the skin. There are now methods for that too, for example with microneedling.”
Njoo’s approach consists of a treatment that focuses on several aspects involved in melasma. With this multilevel treatment (the production of) melanin is tackled at 4 points. In addition to inhibiting production with tyrosinase inhibitors, deeper pigment is also destroyed, the skin is protected against light and pigment production is inhibited with systemic treatment. Njoo: “Tyrosinase inhibitors are important for inhibiting melanin production. These are now available in all shapes and sizes and are often safer than the formerly widely used hydroquinone cream. A good sunscreen is also important. It turns out that mineral-based filters work best for melasma. However, it is a misunderstanding that people with dark-colored skin should apply an SPF 50 cream. People with skin type 1 or 2 do benefit from SPF 50, because they burn quickly, but someone with colored skin needs SPF 30.”
In addition, Njoo also uses systemic treatment aimed at growth factors, such as tranexamic acid. Njoo: “This medicine inhibits the development and proliferation of blood vessels in the skin. In addition, this hypothetically also reduces blood flow to the skin and thus there is less hormonal stimulation for the production of melanin. You can either apply this topically, in the form of a serum or lotion, or you can take it orally. Personally, I have a lot of experience with oral therapy and sometimes that alone is effective.”
Furthermore, melanin can be tackled with the help of a laser treatment. It is important to use the right type of laser, emphasizes Njoo. “The lasers used before give off too much heat and are also too slow. This leads to more inflammatory reactions and more redness after laser treatment, which is unfavorable for melasma. Today we work with picosecond lasers with a special melasma head. This makes it much safer to remove the pigment present.”
Sun no friend
Njoo is strongly in favor of multi-target treatment, especially if the discoloration has been present for a long time. Njoo: “You can try a classic triple cream for the onset of melasma. Especially if the damage is not so bad, you can achieve results with it. But in people who have long-term, refractory melasma, that’s not enough. The key to success lies in combining, continuously fine-tuning the treatment and providing lifestyle advice. People have to accept that the sun is no longer a friend. Because above all: the sun is the most important factor in this story.”
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