Topical therapies for melasma and disorders of hyperpigmentation

Abstract

Facial hyperpigmentation is usually a reflection of an increased amount of melanin either within the epidermis, the dermis, or both (mixed pattern). The increase in melanin content is due to an increased number of functioning melanocytes (melanocytosis), an increased amount of melanin production without a numerical alteration of melanocytes (melanosis), or both. Topical hypo/depigmenting agents are most effective in those disorders where the increased melanin pigment (secondary to melanocytosis or melanosis) is within the epidermis. In patients with melasma, one of the more common causes of facial hyperpigmentation, two major groups of hypo/depigmenting agents have been used: phenolic derivatives and nonphenolic compounds. Hydroquinone, a phenolic derivative, has been used most extensively. It is applied to areas of involvement, either alone or in combination with one or two of the following: tretinoin, salicylic acid, glycolic acid, or corticosteroid. Phenolic thioethers are a new class of phenolic derivatives, and they exhibit both cytocidal and cytostatic effects selectively on melanocytes. Nonphenolic depigmenting agents include azelaic acid and kojic acid. If the facial hyperpigmentation is not improved by first‐line topical therapies, chemical peels may be used in combination. The precise cause of melasma is not known, and multiple factors have been implicated. However, a genetic predisposition and exposure to ultraviolet (UV) light are very important factors. Avoidance of direct exposure to sunlight and application of broad‐spectrum sunscreens are required during and after the period of active treatment. In addition to melasma, other causes of facial hyperpigmentation include Riehl's melanosis, photocontact dermatitis, the sequelae of inflammatory diseases such as acne vulgaris and cutaneous lupus, and nevus of Ota.

Review of Topical Lightening Agents

“…The 5% concentration of hydroquinone may also be compounded with 0.5% ascorbic acid in a low-potency corticosteroid base to increase penetration and reduce irritation, respectively. An improvement in the hyperpigmentation may be noticeable after 4 weeks of therapy but the optimal effect is typically achieved after 6-10 weeks of therapy [9]. Prolonged daily use of 4-5% hydroquinone can lead to a high incidence of irritant reactions particularly when combined with retinoic acid [9].…”

“…A triple combination cream in a stabilized formulation, containing 4% hydroquinone, 0.05% tretinoin, and 0.01% fluocinolone acetonide, has been demonstrated to be both safe and effective in the treatment of moderate to severe melasma [6,[9][10][11] and has also been successfully used in the treatment of PIH, although formal clinical studies are needed.…”

“…Azelaic acid is a dicarboxylic acid isolated from Pityrosporum ovale, the organism responsible for pityriasis versia color [9].…”

Phenotype-based screening of selected mangrove methanolic crude extracts with anti-melanogenic activity using zebrafish (Danio rerio) as a model

“…Melanin is important in the protection of human skin from the harmful effects of UV light radiation and in the scavenging of free radicals generated within the cytoplasm. However, excessive production and abnormal distribution of melanin may cause serious aesthetic problems particularly hyperpigmentation disorders such as melasma, Riehl's melanosis, and postinflammatory hyperpigmentation 3 . Hyperpigmentation or skin darkening is one of the most prevalent dermal conditions which is particularly resistant to treatment.…”

Double Blind Placebo Controlled Trial to Evaluate of the Effectiveness of a Dietary Supplement Rich in Carotenoids as Adjunct to Topical Lightening Cream for the Treatment of Melasma: A Pilot Study

“…Melasma is a prominent skin problem, especially amongst dark skin individuals, presenting with varying degrees of hyperpigmentation on sun-exposed areas of the skin [1]. And has a significant psychosocial impact [2,3].…”