Pigmentary disorders

The pathogenesis of hypopigmentation

Paolo Custurone

As growing concern indicates, hypopigmented dermatoses represent a cosmetic concern at the least and a severely impactful group of conditions on the personal and social lives of patients affected. Although this group of conditions is very heterogeneous in nature and pathogenesis, vitiligo is one of the most common and most studied. As a chronic dermatosis, vitiligo has been studied not just for possible solutions which try to camouflage the skin manifestations, but also on a fundamental, etiopathogenetic side. Research in this sense has demonstrated that vitiligo is not just a melanocyte deficit in the skin, but rather a condition that is often inscribed in a far more complex clinical picture, in which the patients tend to develop other conditions, often related to autoimmunity. As studies and research are made in this field, it has been found that this hypopigmentation can be caused or exacerbated by several factors. HLA haplotypes, genes that encode for tyrosinases and proliferating factors represent the gene apparatus on which vitiligo thrives. On a superior level, small non-encoding RNAs have also been indicated as possible inhibitors of melanin production. The internal cellular environment has been researched as more and more studies focus on the role of oxidative stress and the enzymatic pathways which protect melanocytes from oxidative damage. Finally, adhesive molecules, cytokines, and immune system cells complete this complex pathogenesis, drawing a picture in which a primary stimulus triggers an immune response whose actors are mainly represented, but not limited to, T-effector cells.

Recommendations for the management of people with vitiligo

Viktoria Eleftheriadou (United Kingdom)

Vitiligo is an acquired chronic depigmentation disorder, which affects between 0.5-1% of the population worldwide. In this lecture, The British Association of Dermatologists (BAD) guideline for the management of vitiligo will be presented, with highlighted recommendations for practical use in both primary care and in a dermatology clinic in secondary care, in addition to updated patient information.

A systematic literature search of PubMed, MEDLINE, EMBASE, Cochrane and AMED databases was conducted to identify key articles on vitiligo up to May 2019. Evidence from the quality of included studies was graded according to the GRADE system (high, moderate, low or very low quality). The guideline aims to address important, practical clinical questions and provide research recommendations.

9600 studies were identified, of which 13 systematic reviews, 30 comparative studies and 73 non-comparative studies were included.
General recommendations included the following:

Screening all patients with vitiligo for the level of psychological distress during initial assessment is recommended
In progressive vitiligo, combination of NB-UVB (whole body or localised) with topicals is recommended
In rapidly progressive vitiligo, combination of NB-UVB with oral betamethasone to arrest disease activity is recommended
For vitiligo on hands and feet, combination of CO2 laser and 5-FU, should be considered

Pigmentation induced by visible light: How to prevent?

Thierry Passeron (France)

Ultraviolet radiations are known to play a central role in the regulation of skin pigmentation. Since more than a decade now, the high energy visible light (blue and violet light) has also been shown to be capable of stimulating an acquired hyperpigmentation in melanocompetent skins but also to have a key role in worsening many hyperpigmentary disorders such as melasma, actinic lentigos or post-inflammatory hyperpigmentation. Thus, there is a strong rationale to protect the skin from those wavelengths in these indications. Several sunscreens are now claiming to protect against visible light but there is a wide variation in the real protection they are offering. Recently, recommendations on how to assess this protection and a proposed VL-protection factor have been published to help patients and clinicians choosing the most adapted products.

The objectives of this presentation will be to review the actual data on the role of VL in pigmentation and pigmentary disorders, but also to better understand how to protect against those wavelengths and how to choose the adapted sunscreens.

Melasma challenges

Zoe Apalla (Greece)

Melasma is considered a challenging dermatosis in terms of treatment because:

It is triggered by a long-lasting multifactorial process
Current treatments often result in inconsistent therapeutic outcomes
Treatments are associated to a certain risk of adverse events
Patients experience frequent relapses despite successful clearance
In this presentation we will analyze the new aspects in melasma pathogenesis and implications in the development of our therapeutic strategies. Considering the multi-factorial etiopathogenesis of melasma, our efforts towards treatment and long-term maintenance of the therapeutic outcome should be more holistic, covering all the different implicated aspects in the development and recurrence of this challenging disease. Furthermore, we will overview conventional versus “new” treatment procedures. In the end we will highlight the therapeutic challenges and the unmet needs in melasma management.

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