Facts About Melasma
Melasma is a form of hyperpigmentation that typically displays on the face and is primarily associated with pregnancy and sun exposure. Early records documented melasma only in pregnant women, which is why it is also labelled as a “mask of pregnancy”. The main contributing factor for melasma during pregnancy is an increased level of the female sex hormone estrogen and placental hormones. Women on “the pill” (birth control contraception) often develop melasma, which reinforces the belief that estrogen is to blame. However, melasma also affects women who have no history of pregnancy or taking the pill; it affects men  and the transgender population .
The sun, often blamed and therefore shunned, is the other main factor believed to cause melasma. This is not an entirely wrong assumption since the sun is known to form the most common type of hyperpigmentation, the tan. But how is it possible that more and more people develop melasma while humans spend more time indoors than we have over the last hundred years? The clients I have consulted have rigorously used sunscreen daily out of fear of forming more pigmentation. The use of sunscreen had neither prevented brown patches nor led to fading. This raises the question: What factors other than oral contraceptives, pregnancy or sun exposure drive this skin condition?
Elevated estrogen levels can indeed cause hyperpigmentation, but estrogen can rise by several external factors. Some of these factors are chemicals that hide in cosmetic products. Ironically, despite the belief that sunscreen is essential for people with melasma, some UV filters act as hormone disruptors resulting in increased estrogen levels. Oxybenzone, for example, is a widely used chemical UV filter and is known to mimic estrogen.
Additionally, many sunscreens do not have equivalent UVA and UVB filters in their formula. The main concern of sunscreen developers and formulators is to prevent sunburn. Sunburn is caused by UVB light. Because the main goal is to prevent sunburn, manufacturers often focus on UVB protection. Hence the SPF claim (15, 20, 30, 50+) on the bottles often only stands for the UVB filter, not the UVA filter . A broad-spectrum sunscreen will have filters for both types of UV, but the UVA filter might be lower. That means the two types of rays are split into different degrees of protection and penetration, which can aggravate pigmentation.
The pattern of melasma is significant, as it appears symmetrically and favours the cheeks, forehead, nose and upper lip area. People with naturally darker skin types are more prone to develop melasma. Regarding the skin cells, it is typical that the melanocytes are bigger and contain more melanin than usual, while their actual number is not increased. Furthermore, the hyperpigmented areas in melasma are not only found in the epidermal layer, where brown pigment should be but also underneath, the dermal layer (dermis). The fact that lesions are found in the dermis is likely a reason why melasma is harder to treat. Tattoos, for example, are purposely placed in the dermis to make them last forever.
Wood’s lamps are widely used in skin therapy studios as skin diagnosis tools. When examining the skin, this lamp is a helpful tool to find out if pigmentation is present in the dermis. If the melasma lesions, or part of them, are not visible under the wood’s lamp, we have dermal pigmentation. The reason is simply that the light emitted by the wood’s lamp cannot reach into the deeper dermal layers. You only see what is in the epidermis.