Azelaic acid and glycolic acid combination therapy for facial hyperpigmentation in darker-skinned patients: a clinical comparison with hydroquinone

Disorders of hyperpigmentation. Part II. Review of management and treatment options for hyperpigmentation

Key challenges in the management of pigmentary disorders such as melasma and postinflammatory hyperpigmentation are their resistance to treatment, tendency to recur after treatment, and the risk of exacerbating hyperpigmentation with many treatment modalities. The second article in this 2-part continuing medical education series on pigmentary disorders focuses on the evidence behind medical and procedural treatments of dyschromias, including photoprotection, topical lightening agents, oral agents, chemical peels, and laser therapy.

Clinical evaluation of anti-aging effects of combined therapy-Azelaic acid, phytic acid, and vitamin C applied layer by layer in females with Fitzpatrick skin types II and III

INTRODUCTION

Vitamins C, E, and A and substances of plant origin, including azelaic acid and phytic acid are frequently used in cosmetic preparations to counteract oxidative stress and negative effects of free radicals. The aim of the study was to evaluate a novel combined therapy consisting of azelaic acid, ascorbic acid, and phytic acid applied layer on layer.

METHODS

Twenty study participants received a series of eight treatments performed every 7 days. Twenty percent azelaic acid and then 30% phytic acid were applied to the entire face, while 40% l-ascorbic acid only on the left side. The preparations were applied layer by layer. Skin parameters were measured before the series of treatments (T0), after the series of eight treatments (T1-8 weeks), and 1 month after the end of the treatment (T2-12 weeks).

RESULTS

The application of two and three active compounds resulted in a significant improvement in erythema and hyperpigmentation both on the forehead and the cheeks, however, more pronounced effects were observed when all the three active compounds were used. Both applied types of treatment considerably increased skin moisture. All the participants (100%) were satisfied with the effects of the treatment. A majority of them reported an improvement in skin hydration, firmness, and elasticity, more uniform skin tone and a reduction of skin redness and wrinkles.

CONCLUSIONS

Topical application of these active compounds resulted in improvement of skin elasticity and flexibility, reduction of wrinkles, hyperpigmentation, erythema, and telangiectasia as well as amelioration of skin tone.

Treatment of hyperpigmentation after burn: A literature review

OBJECTIFY

Skin pigmentation disorders are one of the most frequent sequelae after burn injury. While these conditions often improve over time, some are permanent and cause severe psychological disorders (especially on the face). Given the frequency of these disorders and their benign nature, the scientific community has great difficulty postponing these patient follow-ups. Publications on their management are rare, and there is no consensus on the gold standard treatment for skin dyschromia. Herein, we performed a literature review including the various treatments currently proposed to manage these hyperpigmentations.

METHODS

All reported articles up to February 2021 were reviewed on Pubmed. Studies on the treatment of hyperpigmented scars were included if they were secondary to burn injuries. Excluded articles evaluated transient treatments, such as makeup, and articles on inflammatory hyperpigmentation without etiological details or not secondary to burns.

RESULTS

201 articles were identified, and 13 studies were included. Topical creams used in inflammatory hyperpigmented lesions such as hydroquinone and first-line retinoids are controversial due to their inconstant efficacy. Various types of laser and pulsed light treatments have shown their effectiveness but can also aggravate pigmentation.

CONCLUSION

Dyschromia after burn remains a therapeutic challenge. Hyperpigmentations after burn should be treated on a case-by-case basis, using data from the literature, clinical experience and measuring the risk/benefit ratio.

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.

Postinflammatory Hyperpigmentation: Epidemiology, Clinical Presentation, Pathogenesis and Treatment

Postinflammatory hyperpigmentation (PIH) is a reactive hypermelanosis that develops following cutaneous inflammation. Common causes of PIH include intrinsic skin conditions (e.g., acne and eczema) as well as external insults to the skin, such as burn injuries and dermatologic procedures. PIH more commonly occurs in individuals with darker skin, for whom it is often a source of significant psychological distress. Several therapeutic modalities are available for the treatment of PIH, including topical agents, chemical peels, and energy-based devices. We review the epidemiology, clinical presentation, pathogenesis, and treatment of PIH.

Facial Hyperpigmentation in Skin of Color: Special Considerations and Treatment

Differences in cutaneous diseases in people of color call for nuanced evaluation and management. One of the most common dermatological complaints from patients with skin of color is dyspigmentation, particularly hyperpigmentation. The challenge for clinicians is to establish correct diagnoses along with consistently successful treatments to meet the needs of the increasingly diverse population served. This review focuses on facial hyperpigmentation and outlines the most common skin disorders and treatment options.

The complex therapy of acne rosacea with azelaic acid preparations

The present literature data on pathogenesis and treatment of acne rosacea are reported in the article. Research results on effectiveness of therapy with azelaic acid at patients with acne rosacea are presented. The nosotropically based standard of acne rosacea therapy is accepted in virtue of the world practice data.

Experience of applying azelaic acid in dermatology

The article presents current published data on 30 years of experience in applying of azelaic acid in dermatology. Data on pharmacokinetics, efficacy and safety in the international practice; results of study and therapeutic efficacy of different dosage forms are presented.

Inorganic layered double hydroxides as a 4-hexyl resorcinol delivery system for topical applications

In this study, the hydrophobic even skin tone active, 4-hexylresorcinol is intercalated into a Zn–Al layered double hydroxide by co-precipitation method and used as controlled release ingredient in a skin care formulation.

Therapy of acne: azelaic acid and basic care

The review covers current concepts of the pathogenesis of acne. It presents the data of international and Russian clinical studies conducted to assess the efficacy and safety of drugs comprising 15% azelaic acid and used for the treatment of acne. The authors describe mechanisms of the effect of azelaic acid on major stages of the pathogenesis of acne. They substantiate the need in basic care in the treatment of acne by the example of products of the JOYSKIN line. The authors discuss the effect of different components of skin care products on the acne-prone skin.

Rationale of using hypopigmenting drugs and their clinical application in melasma

Among the pigmentary disorders, melasma is the prototype disorder characterized by hyperpigmentation. Although, conventionally, triple combination creams are used, there is a need for alternatives to hydroquinone as the drug has restrictions on its widespread use. This needs an understanding of the steps involved in the melanogenesis and the drugs that inhibit the key steps. The data on in vitro inhibition need to be then translated into clinical in vivo results, before a rationale compounded fixed drug preparation is marketed that inhibits the major steps in the pigmentation pathway. There is also a need to look for drugs that are superior to hydroquinone, as only then will they have a meaningful clinical utility. For now, a few drugs like deoxyarbutin, ellagic acid, dioic acid, n-butylresorcinol and azelaic acid have such properties in clinical trials, while metformin is a recent addition.

Experience use of azelaic acid in patients with acne

Treatment of acne is one of the important problems of modern dermatology. The goal of the research. The study of clinical efficacy and safety of the 15% azelaic acid in the form of Azelik-gel in the treatment of patients with papulo-pustular acne, mild to moderate in severity. Material and methods. Open comparative study of 8 weeks, which was attended by 75 patients. To assess the safety and efficacy of the therapy was performed clinical and biochemical blood and urine tests, evaluation of dermatological status, measurement of pH, moisture and oiliness of skin and analysis of DLQI. Results. 82% of patients receiving the Azelik-gel, marked clinical improvement or significant improvement. Conclusions. The results of the study indicate a high level of safety and tolerability of the Azelik-gel and obtained clinical results have shown its therapeutic efficacy in the treatment of papulo-pustular acne mild to moderate in severity.

Antimicrobial activity of untypical lipid compounds in the cuticular and internal lipids of four fly species

AIMS

This article describes the qualitative and quantitative analyses of untypical compounds in the cuticular and internal lipids of four dipteran species. For isolated compounds, antimicrobial activity against 18 reference strains of bacteria and fungi was determined.

METHODS AND RESULTS

In this study, gas chromatography (GC) combined with mass spectrometry (GC-MS) was used to analyse the surface and internal compounds of four fly species. Seven untypical compounds from both pre-imaginal and imaginal stages of examined insects were identified. Azelaic acid (AA) was the most abundant, while phenylacetic and phenylpropionic acids occurred in lower concentration. Minor quantities of sebacic acid, 2-methyl-2-hydroxybutanoic acid, tocopherol acetate and trace amounts of 2,4-decadienal were also detected. Tocopherol acetate was found only in cuticular lipids of Musca domestica larvae. Each compound was tested against several species of fungi and bacteria by determining minimal inhibitory concentration (MIC). Human pathogenic fungi were also investigated. Phenylpropionic acid showed the greatest antifungal activity. Bacterial strains were insensitive to the presence of identified compounds, apart from 2,4-decadienal which strongly inhibited bacterial growth.

CONCLUSIONS

This is the first time that the chemical composition and the antimicrobial activity of untypical compounds in the cuticular and internal lipids of four fly species has been analysed.

SIGNIFICANCE AND IMPACT OF THE STUDY

Determination of untypical compounds and their antimicrobial activity can effectively contribute to the knowledge concerning insect defence mechanisms.

Effects of cosmetic formulations containing hydroxyacids on sun-exposed skin: current applications and future developments

This paper describes recent data on the effects of various skin formulations containing hydroxyacids (HAs) and related products on sun-exposed skin. The most frequently used classes of these products, such as α- and β-hydroxyacids, polyhydroxy acids, and bionic acids, are reviewed, and their application in cosmetic formulations is described. Special emphasis is devoted to the safety evaluation of these formulations, particularly on the effects of their prolonged use on sun-exposed skin. We also discuss the important contribution of cosmetic vehicles in these types of studies. Data on the effects of HAs on melanogenesis and tanning are also included. Up-to-date methods and techniques used in those explorations, as well as selected future developments in the cosmetic area, are presented.

Postinflammatory hyperpigmentation: etiologic and therapeutic considerations

Postinflammatory hyperpigmentation (PIH) is a reactive hypermelanosis and sequela of a variety of inflammatory skin conditions. PIH can have a negative impact on a patient's quality of life, particularly for darker-skinned patients. Studies show that dyschromias, including PIH, are one of the most common presenting complaints of darker-skinned racial ethnic groups when visiting a dermatologist. This is likely due to an increased production or deposition of melanin into the epidermis or dermis by labile melanocytes. A variety of endogenous or exogenous inflammatory conditions can culminate in PIH and typically most epidermal lesions will appear tan, brown, or dark brown while dermal hypermelanosis has a blue-gray discoloration. Depigmenting agents target different steps in the production of melanin, most commonly inhibiting tyrosinase. These agents include hydroquinone, azelaic acid, kojic acid, arbutin, and certain licorice (glycyrrhiza) extracts. Other agents include retinoids, mequinol, ascorbic acid (vitamin C), niacinamide, N-acetyl glucosamine, and soy, and these products depigment by different mechanisms. Certain procedures can also be effective in the treatment of PIH including chemical peeling and laser therapy. It is important to note that these same therapeutic modalities may also play a role in causing PIH. Lastly, those lesions that are not amenable to medical or surgical therapy may experience some improvement with cosmetic camouflage.

Interventions for melasma

BACKGROUND

Melasma is an acquired symmetrical pigmentary disorder where confluent grey-brown patches typically appear on the face. Available treatments for melasma are unsatisfactory.

OBJECTIVES

To assess interventions used in the management of all types of melasma: epidermal, dermal, and mixed.

SEARCH STRATEGY

In May 2010 we searched the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials) in The Cochrane Library, MEDLINE, EMBASE, PsycINFO, and LILACS. Reference lists of articles and ongoing trials registries were also searched.

SELECTION CRITERIA

Randomised controlled trials that evaluated topical and systemic interventions for melasma.

DATA COLLECTION AND ANALYSIS

Study selection, assessment of methodological quality, data extraction, and analysis was carried out by two authors independently.

MAIN RESULTS

We included 20 studies with a total of 2125 participants covering 23 different treatments. Statistical pooling of the data was not possible due to the heterogeneity of treatments. Each study involved a different set of interventions. They can be grouped into those including a bleaching agent such as hydroquinone, triple-combination creams (hydroquinone, tretinoin, and fluocinolone acetonide), and combination therapies (hydroquinone cream and glycolic acid peels), as well as less conventional therapies including rucinol, vitamin C iontophoresis, and skin-lightening complexes like Thiospot and Gigawhite.Triple-combination cream was significantly more effective at lightening melasma than hydroquinone alone (RR 1.58, 95% CI 1.26 to 1.97) or when compared to the dual combinations of tretinoin and hydroquinone (RR 2.75, 95% CI 1.59 to 4.74), tretinoin and fluocinolone acetonide (RR 14.00, 95% CI 4.43 to 44.25), or hydroquinone and fluocinolone acetonide (RR 10.50, 95% CI 3.85 to 28.60).Azelaic acid (20%) was significantly more effective than 2% hydroquinone (RR 1.25, 95% CI 1.06 to 1.48) at lightening melasma but not when compared to 4% hydroquinone (RR 1.11, 95% CI 0.94 to 1.32).In two studies where tretinoin was compared to placebo, participants rated their melasma as significantly improved in one (RR 13, 95% CI 1.88 to 89.74) but not the other. In both studies by other objective measures tretinoin treatment significantly reduced the severity of melasma.Thiospot was more effective than placebo (SMD -2.61, 95% CI -3.76 to -1.47).The adverse events most commonly reported were mild and transient such as skin irritation, itching, burning, and stinging.

AUTHORS' CONCLUSIONS

The quality of studies evaluating melasma treatments was generally poor and available treatments inadequate. High-quality randomised controlled trials on well-defined participants with long-term outcomes to determine the duration of response are needed.

Skin-lightening products revisited

Skin colour typology depends on the amount and location of its chromophores. Among them, eumelanins derived from 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI), and phaeomelanins are of utmost importance. These biomolecules result from the multi-step enzymatic and non-enzymatic conversion of tyrosine into melanins. Pigmentation disorders are multiple and depend on alterations in the density in active melanocytes, and on specific abnormalities of any of the complex melanogenesis mechanisms. This review presents some of the main skin-lightening agents with respect to their mechanisms of action and side-effects. Some of the novel compounds may lead to new perspectives in the fields of dermatology and cosmetology. The methods commonly used to assess efficacy of skin-lightening products rely on in vitro models including cell-free enzymatic assays, melanocyte cultures and reconstructed epidermis bioassays. Animal models have little relevance. By contrast, human testing with the support of instrumental evaluations is the most informative.

Melasma in Latin America: options for therapy and treatment algorithm

OBJECTIVE/AIM

To examine approaches to therapy for melasma in Latin Americans and to propose treatment algorithms for patients with mild, moderate and severe melasma.

BACKGROUND

Melasma is prevalent in up to 10% of the Latin American population. It is found in all racial groups and is more common in subjects with darker skin phototypes. A number of topical treatments and procedures have been used for melasma. Topical treatments containing hydroquinone are the most popular. Care must be taken when treating melasma to avoid inducing post-inflammatory hyperpigmentation and ochronosis. Determination of the severity of melasma (using the Melasma Area Severity Index and/or Physician's Global Assessment) and choice of the most effective and suitable treatment and/or procedure for individual patients is therefore essential. Sun protection is mandatory for all melasma patients.

METHODS

Thirty-one clinical studies of topical treatments, chemical peels and laser and other therapies used for treating melasma were assessed for the level and quality of clinical evidence, by the Latin American Pigmentary Disorders Academy. The results of this analysis were combined with differential diagnosis guidelines and methods for assessing treatment success to establish algorithms for treating mild and moderate-to-severe melasma.

RESULTS

The most appropriate first-line treatment for mild melasma is hydroquinone 4%, triple combination cream containing hydroquinone 4%, tretinoin 0.05% and fluocinolone acetate 0.01%, double combination (e.g. 4% hydroquinone and 0.1% tretinoin) or non-phenolic therapy where there is an allergy to compounds. In moderate-to-severe melasma, triple combination cream is the recommended first-line treatment. Second-line treatment is double combination or hydroquinone 4% where triple therapy is not available or if allergic to compounds. Sun avoidance measures and broad spectrum sunscreens with high SPF are fundamental for the successful management of the disease.

Management of hyperpigmentation in darker racial ethnic groups

Dyschromias, in particular hyperpigmentation, are major issues of concern for people of color. Pigmentary disorders such as melasma and postinflammatory hyperpigmentation (PIH) can cause psychological and emotional distress and can pose a negative impact on a person's health-related quality of life. The precise etiology of these conditions is unknown. Therapies for melasma and PIH target various points during the cycle of melanin production and degradation. Therapies for these conditions include topical agents and resurfacing procedures. Hydroquinone remains the gold standard of topical agents. Other efficacious agents include kojic acid, azelaic acid, mequinol, and retinoids. Cosmeceutical agents include licorice, arbutin, soy, N-acetyl glucosamine, and niacinamide. Resurfacing procedures that have been used to treat melasma and PIH include chemical peels, microdermabrasion, lasers, and intense pulsed light. These procedures are best used in combination with topical bleaching agents. Given the propensity of darker skin to hyperpigment, resurfacing procedures should be used with care and caution. Maximal results are best achieved with repetitive, superficial, resurfacing modalities. In addition, ultraviolet protective measures such as broad-spectrum sunscreens are fundamental to the successful management of these conditions.

Tazarotene versus tazarotene plus hydroquinone in the treatment of photodamaged facial skin: A multicenter, double‐blind, randomized study

OBJECTIVES

To compare the efficacy and tolerability of tazarotene plus hydroquinone versus tazarotene alone in the treatment of facial photodamage.

METHODS

Patients with facial mottled hyperpigmentation of at least moderate severity and an overall integrated assessment of photodamage score of at least moderate applied tazarotene 0.1% cream each evening and either hydroquinone 4% cream or placebo cream each morning for up to 24 weeks.

RESULTS

Among 131 patients enrolled, 114/124 (92%) with exit data completed. Both regimens were highly effective in reducing photodamage, with tazarotene plus hydroquinone showing superiority over tazarotene alone for some efficacy measures. The incidence of >or=1-grade improvement from baseline (on a scale of none, minimal, mild, moderate, or severe) was significantly greater with tazarotene plus hydroquinone than with tazarotene alone for lentigines (weeks 12-24, p<or=0.01) and mottled hyperpigmentation (week 16, p<or=0.05). The incidence of >or=50% global improvement was also significantly superior with the combination regimen as early as week 8 (p<or=0.01). Both regimens were associated with good tolerability and high patient satisfaction (no significant between-group differences).

CONCLUSIONS

The adjunctive use of hydroquinone can enhance the efficacy of tazarotene in reducing dyspigmentation associated with photodamage.

Hyperpigmentation and melasma

Facial and neck pigmentations are significant cosmetic problems. They are common in middle-aged women, related to endogenous (hormones) and exogenous factors (cosmetics, perfumes, sun exposure), and often represent paramount causes of emotional distress. Although melasma is the most common cause of facial pigmentation, there are many other forms including drug-induced and postinflammatory hyperpigmentation. We review pathogenesis, clinical and histopathological data, effect on quality of life, and treatment options in facial hyperpigmentation disorders.

The safety of hydroquinone: A dermatologist's response to the 2006 Federal Register

Recently, the US Food and Drug Administration proposed a ban on over-the-counter hydroquinone mainly on the basis of high absorption, reports of exogenous ochronosis in humans, and murine hepatic adenomas, renal adenomas, and leukemia with large doses over extended time periods. Systemic exposure to hydroquinone from routine topical application is no greater than that from quantities present in common foods. While murine hepatic adenomas increased, murine hepatocellular carcinomas decreased, suggesting a protective effect. Renal tumors are sex, species, and age specific and therefore do not appear relevant to humans after decades of widespread use. Murine leukemia has not been reproducible and would not be expected from small topical doses. Finally, a literature review of exogenous ochronosis and clinical studies employing hydroquinone (involving over 10,000 exposures under careful clinical supervision) reveal an incidence of exogenous ochronosis in the United States of 22 cases in more than 50 years. Therefore, the proposed ban appears to be unnecessarily extreme.

Azelaic acid (15% gel) in the treatment of acne rosacea

In December of 2002, the FDA approved azelaic acid 15% gel for the topical treatment of inflammatory papules and pustules of mild to moderate rosacea. Azelaic acid is a saturated dicarboxylic acid, which is naturally occurring and has been used in the treatment of rosacea, acne, and melasma. The 15% gel has a high efficacy and is generally well tolerated, with the local irritation (burning, stinging, itching, and scaling) being typically mild and transient. Azelaic acid 15% gel is considered effective and safe as a therapy for inflammatory papulo-pustular rosacea and is suitable for use on all skin types.

The safety of hydroquinone

Hydroquinone is one of the most effective molecules for the treatment of hyperpigmentary disorders, with over 40 years of efficacy and safety data. Concerns over its safety have been raised because of the fact that it is a derivative of benzene and because of the long-term side-effects observed with cosmetic products containing high concentrations of hydroquinone. However, despite 40-50 years use of hydroquinone for medical conditions, there has not been a single documented case of either a cutaneous or internal malignancy associated with this drug. This article reviews the evidence for the safety of hydroquinone in the treatment of hyperpigmentation conditions.

The treatment of melasma: A review of clinical trials

Melasma is an irregular brown or grayish-brown facial hypermelanosis, often affecting women, especially those living in areas of intense UV radiation. The precise cause of melasma remains unknown; however, there are many possible contributing factors. Because of its dermal component and tendency to relapse, melasma is often difficult to treat. The use of broad-spectrum (UVA + UVB) sunscreen is important, as is topical hydroquinone, the most common treatment for melasma. Other lightening agents include retinoic acid (tretinoin) and azelaic acid. Combination therapies such as hydroquinone, tretinoin, and corticosteroids have been used in the treatment of melasma, and are thought to increase efficacy as compared with monotherapy. Kojic acid, isopropylcatechol, N-acetyl-4-cysteaminylphenol, and flavonoid extracts are other compounds that have been investigated for their ability to produce hypopigmentation, but their efficacy, safety, or trial design indicates that the interventions would need further study before they could be recommended. Chemical peels, laser treatments, and intense pulsed light therapy are additional therapeutic modalities that have been used to treat melasma.

Established treatments of skin hypermelanoses

Cutaneous hypermelanoses are frequently encountered conditions that can have severe adverse psychosocial and emotional effects on affected patients. Melasma, postinflammatory hyperpigmentation, drug-induced pigmentation, and erythema dischromicum perstans are among the most common cutaneous disorders leading to acquired skin hyperpigmentation. The treatment of these disorders is often challenging and requires a great deal of patience from the patient and a wealth of experience and knowledge from the dermatologist. Current treatments include depigmenting agents, chemical peels, and lasers. The ideal bleaching agent has to fulfill certain pharmacologic criteria. It should have a potent bleaching effect with a rapid time of onset, carry no side effects, and lead to a permanent removal of undesired pigment. We review the established treatment approaches of cutaneous hyperpigmentation based on literature review and our personal experience.

Melanin pigmentary disorders: treatment update

Most of the melanin pigmentary disorders are cosmetically important and have a strong impact on the quality of life of affected individuals. This article examines recent advances in the treatment of melanin pigmentary disorder including hypermelanosis and hypomelanosis. The development of laser technologies has completed the use of the increasing number of bleaching agents in treating hyperpigmented lesions. The treatment of hypomelanotic disorders is still often disappointing, but new therapeutic options provide encouraging results.

Safety and efficacy of 4% hydroquinone combined with 10% glycolic acid, antioxidants, and sunscreen in the treatment of melasma

BACKGROUND

Melasma, also known as mask of pregnancy, is a common, acquired hypermelanosis seen in women with Fitzpatrick skin types II-V, and is often recalcitrant to treatment with depigmentation agents. Glycolic acid has been added to hydroquinone formulations in the past to enhance their depigmentation effects, but may cause irritation, leading to postinflammatory hyperpigmentation.

AIM

To assess the safety and efficacy of a cream containing 4% hydroquinone, 10% buffered glycolic acid, vitamins C and E, and sunscreen (Glyquin, ICN Pharmaceuticals, Costa Mesa, USA) vs. a cream containing sunscreen alone in the depigmentation of epidermal melasma of the face.

METHODS

Thirty-nine Hispanic women, Fitzpatrick skin types III-V, with bilateral epidermal melasma were enrolled in a randomized controlled trial lasting 12 weeks. Patients underwent twice-daily full-face application with the study cream or with the cream containing sunscreen only. Changes in pigmentation were measured using a mexameter, the melasma area and severity index (MASI), and a global evaluation by the patient and blind investigator. Safety evaluations were performed at each follow-up visit.

RESULTS

Thirty-five patients completed the trial. Irritation was more common with the study cream, but resolved with temporary cessation of cream application and the addition of moisturizers. Mexameter results demonstrated a significant decrease in the degree of pigmentation using the study cream compared with the cream containing sunscreen alone (P < 0.0001). Fifteen of 20 patients (75%) using the study cream improved, whereas only two of 15 patients (13%) improved using sunscreen alone.

CONCLUSIONS

A cream containing 4% hydroquinone, 10% buffered glycolic acid, vitamins C and E, and sunscreen is safe and effective in the treatment of melasma.

The inhibitory effect of glycolic acid and lactic acid on melanin synthesis in melanoma cells

Alpha-hydroxy acids (AHAs) such as glycolic acid (GA) and lactic acid (LA) have been reported to be effective in treating pigmentary lesions such as melasma, solar lentigines, and postinflammatory hyperpigmentation. The mechanism of this effect might be due to epidermal remodeling and accelerated desquamation, which would result in quick pigment dispersion. However, the direct effect of AHAs on melanin synthesis has not yet been well studied. To elucidate such a direct effect of AHAs on melanogenesis, we performed melanin assays, growth curve determinations, Northern and Western blotting for melanogenic proteins [tyrosinase, tyrosinase related protein (TRP)-1 and TRP-2], and tyrosinase and, 4-dihydroxyphenylalaninechrome tautomerase enzyme activity assays using mouse B16 and human melanoma cells. GA or LA (at doses of 300 or 500 microg/ml) inhibited melanin formation in similar dose-dependent manner, without affecting cell growth. Although the mRNA and protein expression or molecular size of tyrosinase, TRP-1 and TRP-2 were not affected, tyrosinase activity was inhibited. To see whether GA and/or LA directly inhibit tyrosinase catalytic function, the effect of GA and LA on human tyrosinase purified from the melanosome-rich large granule fraction of human melanoma cells was performed. GA or LA were shown to inhibit tyrosinase enzyme activity directly, but this effect was not due to the acidity of GA or LA, because adjusting the pH to 5.6 (the pH of GA and LA at concentrations of 2500 microg/ml), did not affect tyrosinase activity. Taken together, these results show that GA and LA suppress melanin formation by directly inhibiting tyrosinase activity, an effect independent of their acidic nature. GA and LA might work on pigmentary lesions not only by accelerating the turnover of the epidermis but also by directly inhibiting melanin formation in melanocytes.

A comparative study of 20% azelaic acid cream monotherapy versus a sequential therapy in the treatment of melasma in dark-skinned patients

BACKGROUND

Melasma is a commonly found hyperpigmentary disorder in dark-complexioned persons, which is rather difficult to treat. Azelaic acid (AZA) 20% is considered efficacious in the treatment of melasma, although the response is rather slow. It has also been combined synergistically with topical retinoic acid, where the results were satisfactory.

OBJECTIVE

The study was done to evaluate the usefulness of a sequential therapy of potent topical steroids +20% AZA cream versus only 20% AZA cream in the treatment of melasma.

METHODS

This was a prospective, single-blind, right-left comparison pilot study with (1). twice daily application of 20% AZA to one half of the face for 24 weeks and (2). a potent topical steroid, 0.05% clobetasol propionate cream, to be applied for 8 weeks only and then to be followed by 20% AZA cream only for the next 16 weeks on the other half. Concomitant use of a broad-spectrum sunscreen was also mandatory. Thirty Indian patients (25 females, 5 males), whose ages ranged from 21 to 45 years and who were not pregnant, nursing or on any concurrent therapy, completed the study. Clinical evaluation, photography and the overall response were assessed at 4, 8, 16 and 24 weeks.

RESULTS

At 4, 8 and 16 weeks, the lightening of melasma was significantly more marked on the side receiving the sequential therapy rather than the side receiving only 20% AZA cream (p < 0.001). However, at 24 weeks, although the difference was still significant (p = 0.0052), as many as 96.7 and 90% of patients of each group (sequential therapy and AZA) had good to excellent responses to treatment. The side-effects noted were mostly mild and transient and mainly local irritant effects.

CONCLUSIONS

A sequential therapy of topical potent steroids +20% AZA cream can be considered as another alternative treatment for melasma, which combines the beneficial effects of both besides perhaps increasing the compliance of the patients. 20% AZA monotherapy itself is also an effective and well-tolerated therapy for melasma in dark-skinned races.