Efficacy of topical cysteamine hydrochloride in treating melasma: a systematic review

Research situation, hot spots, and global trends of melasma therapy: Bibliometric insights and visual analysis from 2000 to 2023

BACKGROUND

Melasma is a prevalent pigmented disease, yet its pathogenesis remains unclear, posing challenges for effective treatment. Bibliometric analysis, a novel approach to literature research, offers the opportunity to evaluate research trends through qualitative and quantitative methods. This study utilizes bibliometric methods to analyze the existing literature on melasma treatment, examining influential publications, institutions, countries, and authors through statistical analysis.

METHODS

In order to retrieve manuscripts related to the topic of melasma treatment, we conducted a search using the search formula: (TS = (melasma or Chloasma or "mask of pregnancy")) AND TS = (treatment or therapy). We searched through the Web of Science Core Collection database, covering publications from 2000 to 2023. VOSviewer, CiteSpace and the Bibliometric online site (https://bibliometric.com/app) were used to conduct this bibliometric analysis. Our analysis focused on various factors including publications, authors co-authorship, institutions, countries, citation analysis, keywords co-occurrence, references co-citation and journal co-citation.

RESULTS

A total of 943 articles and 200 reviews were published between 2000 and 2023, accumulating a total of 8628 citations. The average number of citations per item was 18.85, and the average number of citations per year was 292.69. The most prolific author, Sungeun Chang, contributed a total of 9 articles. Cario University emerged as the top research institution. The United States led in terms of article publications with a count of 276. In the past 5 years, the research trends in this field have primarily focused on tranexamic acid and epidermal melasma, as indicated by the burst analysis of publications and keywords.

CONCLUSIONS

The United States continues to lead in terms of institutions and research output. The current emphasis is on the meticulous implementation of tranexamic acid and laser therapy. It is crucial to foster enhanced collaboration among countries, institutions, and authors to facilitate improved research.

An Update on New and Existing Treatments for the Management of Melasma

Melasma is a chronic, acquired disorder of focal hypermelanosis that carries significant psychosocial impact and is challenging for both the patient and the treating practitioner to manage in the medium to long term. Multiple treatments have been explored, often in combination given the many aetiological factors involved in its pathogenesis. Therapeutic discoveries to treat melasma are a focal topic in the literature and include a range of modalities, with recent developments including updates on visible light photoprotection, non-hydroquinone depigmenting agents, oral tranexamic acid, chemical peels, and laser and energy-based device therapy for melasma. It is increasingly important yet challenging to remain up-to-date on the arsenal of treatments available for melasma to find an efficacious and well-tolerated option for our patients.

Medical therapies for Melasma

Melasma is a common malady affecting all races with a higher incidence in Hispanics, Middle Eastern, Asians and African origin females (Fitzpatrick skin phototypes III-V). Women are affected much more often than men. Melasma remains a significant cause of cosmetic morbidity and psychosocial embarrassment affecting quality of life necessitating effective and reliable treatment. Unfortunately, treatment remains unsatisfactory due to limited efficacy, adverse effects and relapses after stopping treatment. Although chemical peels, laser and light therapies and dermabrasion may have utility, the evidence available for their efficacy is limited and they often cause post inflammatory hyperpigmentation particularly in individuals with darker skin types. Medical therapies remain mainstay in the management of melasma. The triple combination, hydroquinone 4%, tretinoin 0.05% and fluocinolone acetonide 0.01% (Triluma, Galderma, Ft. Worth Texas, often modified incorporating different corticosteroids) remains the only US FDA approved treatment for melasma and is the gold standard due its demonstrated efficacy across ethnicities. Oral tranexamic acid alone or in combination with other modalities has also shown significant efficacy. Several cosmeceuticals and botanical extracts used as skin lightening agents have been demonstrated to be useful. Physical sunscreens containing zinc oxide, iron oxide, titanium dioxide, and silicones provide photoprotective and camouflage effect. We propose that a multimodality approach to the treatment of melasma is the most effective treatment approach. This review is focused on the medical therapies for melasma.

Efficacy of Cysteamine and Methimazole in Treating Melasma A Comparative Narrative Review

Melasma is a chronic and acquired pigmentary condition that primarily affects women and undermines patient satisfaction and confidence. Melasma mostly affects females, accounting for 90% of all cases. It affects people of all races, particularly those with skin types IV and V who live in areas with lots of UV radiation. According to the studies, Melasma lesions are seen throughout the face in centrofacial, malar, and mandibular patterns. Melasma lesions on the forehead, cheeks, nose, upper lip, and/or chin are the most prevalent centrofacial pattern. Melasma lesions can also be detected along the periorbital area, especially in Asian people. Melasma is notably resistant to treatment, with many patients experiencing only temporary relief and relapses. Combining therapies that target numerous pathologic components, including photodamage, inflammation, aberrant vascularity, and abnormal pigmentation, generally results in the most dramatic therapeutic improvements. Treatments for dark circles include topical depigmenting medicines like hydroquinone, kojic acid, azelaic acid, and topical retinoic acid, and physical treatments such as chemical peels, surgical adjustments, and laser therapy. The objective of therapy should be to figure out what's causing the hyperpigmentation and what's contributing to it. This article provides an overview of melasma therapies and the efficacy of methimazole and cysteamine for melasma therapy.

Metabolic Basis and Clinical Evidence for Skin Lightening Effects of Thiol Compounds

Melanin pigment is a major factor in determining the color of the skin, and its abnormal increase or decrease can cause serious pigmentation disorders. The melanin pigment of the skin is divided into light pheomelanin and dark eumelanin, and a big difference between them is whether they contain sulfur. Melanin synthesis starts from a common reaction in which tyrosine or dihydroxyphenylalanine (DOPA) is oxidized by tyrosinase (TYR) to produce dopaquinone (DQ). DQ is spontaneously converted to leukodopachrome and then oxidized to dopachrome, which enters the eumelanin synthesis pathway. When DQ reacts with cysteine, cysteinyl dopa is generated, which is oxidized to cysteinyl DQ and enters the pheomelanin synthesis pathway. Therefore, thiol compounds can influence the relative synthesis of eumelanin and pheomelanin. In addition, thiol compounds can inhibit enzymatic activity by binding to copper ions at the active site of TYR, and act as an antioxidant scavenging reactive oxygen species and free radicals or as a modulator of redox balance, thereby inhibiting overall melanin synthesis. This review will cover the metabolic aspects of thiol compounds, the role of thiol compounds in melanin synthesis, comparison of the antimelanogenic effects of various thiol compounds, and clinical trials on the skin lightening efficacy of thiol compounds. We hope that this review will help identify the advantages and disadvantages of various thiol compounds as modulators of skin pigmentation and contribute to the development of safer and more effective strategies for the treatment of pigmentation disorders.