A recent review article updates recent research on melasma, commonly referred to as pregnancy mask, indicating it may be more than just related to pregnancy.
Melasma is a common but challenging skin disorder. While it can affect anyone, it is more common among the female population. It is defined as the brownish pigmentation that covers the face in a mask-like distribution, where the borders may be irregular, but in a symmetric pattern. The term “pregnancy mask” is often given to melasma as it usually occurs during a woman’s childbearing years and indeed manifests during pregnancies. Treating the hyperpigmentation remains challenging as current treatments (topical bleaching agents, chemical or laser resurfacing) yield inconsistent results, and recurrence is commonly seen.
The development of melasma is traditionally explained as an effect of the increased female hormone levels during pregnancy. This leads the melanocytes in the face to produce more pigment, leading to the discolouration seen. Why only some females are affected has been attributed to a genetic predisposition, in which their pigment cells are more sensitive to this hormonal trigger.
However, a recent article in the 2018 Pigment Cell and Melanoma Research journal is challenging this long-established presumption. Dermatologists from France and Italy believe that while hormonal stimulation and genetic tendencies remain significant factors, they point to other potential culprits that may lead to the development of melasma.
Does Photo-Aging Play a Role in Melasma?
In studying not just the melanocyte in isolation, but also including the surrounding cellular interactions, the authors theorize that other mediators may affect pigment production. While the pigment cell remains primarily stimulated by female hormones, other skin cells may also play a part in melanin production. The potential damage from solar rays has long been known; ultraviolet radiation causes significant damage to the skin, and this triggers skin cells to release numerous chemical signals as a response.
The primary effects seen are in fact increases in both the number of melanocytes and the amount of pigment produced. This may explain the increased rates of relapse, as well as the worsening of symptoms seen in patients with a history of sun exposure.  Because of this, the authors conclude that melasma should not be seen as simply a hormonal condition, but in fact part of the photo-aging spectrum of skin conditions.
By looking at melasma through this different lens, the authors conclude that more options may be considered in its treatment. Instead of simply addressing the pigmentation that has occurred, as removing the melanin that has already deposited is indeed difficult, newer modalities can target these other identified mediators to minimize melanin production.
And by recognizing the photo-aging component of melasma, both clinician and patient can be made aware of the importance of protection from the harmful rays of the sun—and we all know that prevention is indeed much better than any cure.
Written by Jay Martin, M.D.
Reference: Passeron and Picardo. “Melasma, a photoaging disorder”. Pigment Cell and Melanoma Research. (2018) doi: 10.1111/pcmr.12684 .
