Melasma: Causes & Treatment
Intro
Melasma is described as a chronic skin condition with acquired hyperpigmentation (aka darkening) of the skin that predominately affects females of childbearing age. Melasma is commonly seen as irregular dark patches on the forehead, cheeks, upper lip, and chin. This skin condition is often relapsing/recurring and can affect quality of life and self-esteem. In this blog post, you will learn:
Causes and aggravating factors of melasma
Integrative management of melasma
1) Causes of Melasma
Melasma has been shown to be caused and aggravated by:
Genetics
Hormones
UV/sunlight exposure
How hormones cause melasma
We know that there is a connection between hormones and melasma since melasma happens more in those who are pregnant and those who are taking oral contraceptives. However, we are still yet to fully understand how hormones cause melasma. There is some interesting literature that helps us connect the dots, which suggest how hormones could cause melasma.
There is literature that shows that there is a higher number of estrogen and progesterone receptors in the skin with those who have melasma. And, there is literature that reveals that estrogen can activate melanin-producing cells (called melanocytes), which leads to darkening of the skin. So, it could be suggested that estrogen is a driving factor in melasma. But, what about progesterone? So, the jury is still out on understanding how hormones contribute to melasma!
How Sunlight exposure causes melasma
Sunlight can cause melasma in different ways. First, we know that visible blue light in sunlight directly stimulates melanocytes. Literature tells us that visible blue light activates opsin-3 in melanocytes, which activates melanogenesis-associated transcription factors, tyrosinase, and dopachrome in those same cells. This then causes melanin production. However, tyrosinase and dopachrome can combine together to make a long-lasting protein complex in those same cells, which leads to long-lasting tyrosinase activity, and causing sustained melanin production and hyperpigmentation - leading to what we see in melasma.
Second, we also know that there are higher numbers of mast cells and increased skin dysfunction in the skin of those with melasma, which could explain another way sunlight could cause melasma. Chronic exposure to sunlight and UV radiation can activate mast cells to produce histamines and tryptase:
Histamines can activate the tyrosinase pathway in melanocytes, causing melanin production.
Tryptase causes down-stream activation of matrix metalloprotease (MMP), which can cause basement membrane damage of the skin. Damage to the basement membrane allows movement of melanocytes and melanin deeper into the dermis layer of the skin, which could contribute to the recurring/relapsing nature of melasma.
2) Management Options for melasma
As a licensed naturopathic doctor (ND), I always try to identify the root cause of a person’s symptoms and treat the root cause with integrative measures. Due to the complexity of melasma and how we are still understanding the internal causes of melasma, melasma treatment is currently geared towards symptom management with combined use of topical lightening agents and photo-protective agents. But, as we learn more about melasma, I am hopeful that we can find ways to treat from within from a naturopathic perspective. And, as always, this post is meant to be educational, and always peaks to your doctor before trying or buying anything new!
topical lightening agents
Topical lightening agents work by inhibiting tyrosinase, inhibiting melanocyte function, and/or reducing inflammation. Some topical lightening agents that may be prescribed by doctors or found in skincare products are:
Hydroquinone: Inhbits tyrosinase.
Azelaic acid: Inhbits tyrosinase.
Kojic acid: Inhbits tyrosinase, and works best with hydroquinone.
Tretinoin: Reduces tyrosinase activity.
Corticosteroids: Reduces inflammation and non-selectively reduces melanin production.
Licorice: Inhibits tyrosinase.
Arbutin: Inhibits tyrosinase.
Niacinamide: Inhibits melanin transport.
Tranexamic acid: Reduces melanin production and reduces mast cells.
& more
Photo-protective agents
Photo-protective agents are meant to prevent exacerbation of melasma by sunlight by acting as a physical shield or increasing antioxidants in the skin. Some photo-protective agents that have evidence are:
UV-visible light sunscreen, specifically iron oxide sunscreens: Blocks visible blue light to prevent the effects of UV on melasma.
Polypodium leucotomos: Increases antioxidant defense systems in the body to prevent the effects of UV on melasma.
Glutathione: Small studies have shown that it reduces the appearance of hyperpigmentation by inhibiting tyrosinase.
Melatonin: Acts as an antioxidant and increases glutathione and reduces melanocyte-stimulating hormone receptors.
Cystamine: Protects against UV-induced free radical damage and inhibit tyrosinase.
Silymarin: Acts as an antioxidant and has been shown to be as effective as hydroquinone.
& more
Peels, Lasers, and other Procedures
Beyond topical lightening agents and photo-protective agents, some people may be curious about procedures, such as peels, lasers, and more for melasma. Here’s what literature has to say about some procedures for melasma:
Chemical peels: Glycolic acid peels have been shown to reduce the appearance of melasma when combined with azelaic acid.
Lasers: Lasers have been shown to reduce the the appearance of melasma, but do not provide long-term benefit in treating melasma.
Light therapy: Intense pulsed light (IPL) has been shown to reduce the appearance of melasma, but need to be completed weekly to maintain its effect.
Platelet-rich plasma (PRP): A pilot study revealed that PRP significantly improved melasma within 6 weeks of treatment where 4 treatment sessions were completed every 2 weeks. However, more trials need to be completed as this was just a pilot study.
Summary & Takeaways
Melasma is a complex, chronic skin condition, and we are still trying to understand the complex mechanisms that cause melasma. In this blog post, I spoke about how hormones could cause melasma and how sunlight can cause melasma by directly activating melanocytes and by indirectly activating melanocytes via mast cells. In addition to this, I spoke about some management options that include pharmaceutical and natural options that are geared towards lightening darkened areas and preventing further exacerbation of melasma. As we learn more about melasma, I am hopeful that we can discover novel treatments that address internal imbalances and root causes from a naturopathic standpoint.
This May, I am focusing on different topics in skin health. Last week, I spoke about hormonal acne, and next week I plan on speaking about the skin barrier. To stay up-to-date about future blog posts, click here sure to sign up for my email newsletter. And, if you want to set up an appointment with me, click here.
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