Melasma (Chloasma)

Overview

Melasma is a kind of hypermelanosis of sun-exposed skin that occurs during pregnancy and affects 50-70 percent of pregnant women. It manifests as symmetric hyperpigmented macules that can be confluent or punctuate. The cheekbones, upper lip, chin, and forehead are the most commonly affected areas. The precise method through which pregnancy influences melanogenesis is uncertain.

During the third trimester of pregnancy, estrogen, progesterone, and melanocyte-stimulating hormone (MSH) levels are generally elevated. Nulliparous patients with chloasma, on the other hand, do not have elevated estrogen or MSH levels. Melasma has also been linked to the use of estrogen- and progesterone-containing oral contraceptives.

The finding that postmenopausal women administered progesterone develops melasma whereas those given just estrogen do not suggest that progesterone plays a significant role in the formation of melasma.

 

Melasma definition

Melasma is a skin condition characterized by brown to gray-brown spots on the face. It usually appears on the cheekbones, chin, nasal bridge, forehead, and above the upper lip. It affects women more than males. Melasma is frequently caused during pregnancy. It also has an impact on women who use oral contraception and hormones.

Melasma is derived from the Greek word "melas," which means "black," and alludes to its brownish clinical appearance. The terms "mask of pregnancy," "liver spots," "uterine chloasma," "chloasma gravidarum," and "chloasma virginum" neither fully characterize nor are semantically appropriate, though the term "chloasma" (derived from the Latin chlóos and the Greek cloazein: greenish) is still used in the medical literature.

Disease descriptions can be found in the medical literature dating back to Hippocrates' writings (470-360 BC). The word was used to describe a succession of cutaneous melanization processes, and it was stated that sun exposure, fire heat, cold, and skin inflammations exacerbated it. 

 

Epidemiology

People of all races can be impacted. Melasma is more common in darker skin types than lighter skin types, and it is especially prevalent in light brown complexion types. Women are nine times more impacted than males. Melasma is uncommon before puberty and more prevalent throughout the reproductive years. Melasma affects between 15% and 50% of pregnant women. Depending on the demographic, the prevalence ranges from 1.5 to 33 percent.

Melasma is a prevalent dyschromia that frequently prompts people to seek dermatological treatment. Its occurrence in the population varies depending to ethnic composition, skin phototype, and level of sun exposure.

In a population-based research conducted in 2010, 1500 people from several Brazilian states were polled. 23.6 percent of men and 29.9 percent of women indicated pigmentation issues as the primary reason for seeking dermatological therapy. The prevalence of melasma in the general population is unknown. Changes that have occurred in recent decades as a result of an increase in sun exposure time spent by the people during leisure and everyday activities have not been supported by research.

 

Etiology 

Sun exposure, pregnancy, use of oral contraceptives and other steroids, consumption of certain food items, ovarian tumors, intestinal parasitoses, hepatopathies, hormone replacement therapy, use of cosmetics and photosensitizing drugs, procedures and inflammatory processes of the skin, and stressful events are some of the triggering factors for melasma.

This shows that the formation of melasma is regulated by a variety of variables and is dependent on the combination of environmental and hormonal effects with a genetically sensitive substrate. Melasma is caused by the female sex hormones estrogen and progesterone stimulating melanocytes to produce more melanin pigments when the skin is exposed to sunlight.

 

Genetic

Genetic predisposition may be a major factor in the development of melasma.

  • Melasma is more frequent in women than men.
  • Melasma is more likely to occur in people with light-brown skin who live in sun-exposed areas of the world.
  • Approximately half of those polled have a positive family history of the illness. Melasma has been recorded in identical twins.

 

Sunlight Exposure

UV exposure can trigger lipid peroxidation in cellular membranes, which produces free radicals that can encourage melanocytes to create more melanin.

  • Sunscreens that block UV-B radiation (290-320 nm) do not inhibit UV-A and visible rays (320-700 nm), which encourage melanocytes to generate melanin.

Melasma pigmentation often improves in the winter and deteriorates in the summer (or immediately after intense sun exposure). Furthermore, its populational prevalence is higher in intertropical zones. The use of high-protection-factor sunscreen reduces the severity of the disease by 50% and its occurrence during pregnancy by more than 90%.

UVA and UVB are the primary rays that cause melanogenesis. Infrared and visible light have substantially lower melanogenic potential. Its involvement in the genesis and progression of melasma is unknown. The authors did, however, identify overnight employees exposed to oven heat (e.g., bakers) and professionals exposed to high intensity light (e.g., dentists) who had severe difficulties treating melasma and reported deterioration following exposure to their working circumstances.

 

Hormonal Influences

Hormones may play a role in developing melasma in some individuals.

  • The mask of pregnancy has been seen in obstetric patients. The precise process remains unclear. Estrogen, progesterone, and melanocyte-stimulating hormone levels are typically elevated during the third trimester of pregnancy and may have a role.
  • Nulliparous patients with melasma have no higher amounts of estrogen or MSH but have elevated levels of estrogen receptors inside the lesions. Melasma has also been linked to estrogen- and progesterone-containing oral contraceptives and diethylstilbestrol therapy for prostate cancer.
  • A postmenopausal woman administered progesterone may develop melasma, although those given estrogen alone do not; this suggests that progesterone plays a key role in the formation of melasma. 

 

Thyroid Disease

There is a four-fold increase in thyroid disease in melasma patients.

  • Melasma formation is linked to the presence of melanocytic and lentiginous nevi.
  • This would imply a link between the onset of melasma and the existence of pigmentation.

 

Pregnancy stimulates melanogenesis, especially in the third trimester, and elevated levels of placental, ovarian, and pituitary hormones may explain pregnancy-related melasma. Elevated levels of melanocyte-stimulating hormone (MSH), estrogen, and progesterone also boost transcription of tyrosinase and dopachrome tautomerase, which may be implicated in pigmentation development during this period. 

 

Clinical presentation

Melasma appears in sun-exposed locations, particularly the face and cervical region, and, less typically, the arms and sternum. It is worst in places that receive a lot of sun, such as the cheeks, upper lip, chin, and forehead.

Facial melasma lesions are classified into two categories based on their clinical distribution: centrofacial and peripheral. Lesions of the centrofacial kind are most common in the middle of the face, namely the glabellar, frontal, nasal, zygomatic, upper lip, and chin regions. The fronto-temporal, preauricular, and mandibular branch regions are afflicted in the peripheral form.

At the time of consultation, a high majority of patients report having melasma lesions in both locations. However, the evolutionary dynamics of melasma topographies have yet to be fully explained.

A 2013 research in Brazil on the epidemiological features of facial melasma in Brazilian women found that centrofacial melasma predominated (51.7 percent), followed by mixed melasma (43.4 percent).

The zygomatic (or malar) melasma has been proposed as a categorization independent of other topographies due to its increased prevalence in all series of cases. However, because of its significant co-occurrence with centrofacial kinds, particularly glabellar lesions, it was advocated that zygomatic lesions be classified as centrofacial.

Because patients are frequently postmenopausal women who describe development after considerable sun exposure, and biopsies demonstrate severe actinic damage, exclusively mandibular melasma is unusual and may represent a kind of poikiloderma of Civatte.

A Brazilian study of 302 women with melasma found no distinguishing factors between mandibular and peripheral variants. This study found that 64.8 percent of mandibular lesions were related with parotid lesions, with just two cases (3.7 percent) being isolated/exclusive. An examination of 312 individuals in India indicated just 1.6 percent of cases with purely mandibular melasma. These findings prompt us to consider the potential of categorizing melasma into two types: centrofacial and peripheral.

Although less often (10-14%), additional sites may be implicated at the same time, resulting in extrafacial melasma, which can be linked with any of the other facial patterns.

Melasma of the extrafacial area appears as hyperchromic, uneven, symmetrical skin discolorations in the arms and forearms, neck/cervical and sternal regions, and, finally, the back (dorso). Melasmas of the upper limbs are more common in older, menopausal women and may be related to hormone replacement treatment.

 

QUALITY OF LIFE

Melasma has a substantial influence on appearance, causing mental and emotional anguish and lowering patients' quality of life. Furthermore, there are large expenses associated with medical treatments and operations, the outcomes of which do not always fulfill the expectations of patients.

Melasma distresses people since it mostly affects the face, making it clearly visible and present in daily life. In this context, it has a detrimental influence on patients' quality of life, impacting their psychological and emotional well-being, which frequently drives them to seek the services of a dermatologist.

Patients frequently express feelings of guilt, low self-esteem, anhedonia, discontent, and a lack of drive to leave the house. Suicidal thoughts have been recorded in the literature as well.

Melasma severity can be difficult to quantify due to the variety in presentation. Several validated methods have been developed to assess both the clinical appearance and the psychological consequences of melasma dyspigmentation. Furthermore, these standardized techniques have improved the ability of clinical studies to analyze the therapeutic success of diverse melasma therapies. The Melasma Area and Severity Index (MASI) is a validated scale for assessing the severity of face hyperpigmentation. This is a number score that is determined as an area-weighted score of pigmentation and homogeneity on the forehead, chin, right and left malar cheek.

The modified MASI (mMASI) was constructed after removing homogeneity from the computation owing to the lower interrater reliability of that statistic. It is now linked to the Melasma Severity Score, a global score that takes into account both objective data and the patient's subjective judgment. It's currently being utilized in clinical studies. 

 

Diagnosis 

Melasma diagnosis is primarily clinical, and the dermatologist has no more challenges. Although no laboratory testing are recommended, some studies show that modest thyroid function abnormalities, notably pregnancy- or oral contraceptive pill-related melasma, are connected. In these circumstances, it is prudent to consider thyroid function testing. The use of a wood light aids in the localization of pigment to the dermis or epidermis.

The main differential diagnoses of melasma are:

  • Freckles, 
  • Solar lentigo, 
  • Toxic melanodermia,
  • Riehl's melanosis, 
  • Post-inflammatory hyperpigmentation, 
  • Friction melanosis, 
  • Ochronosis (endogenous and exogenous),
  • Cutaneous erythematosus lupus. 

Melasma dermoscopy (varying magnification from 6 to 400x) reveals highly distinct alterations. The vascular component, which is present in a substantial proportion of cases, may be seen. Melanin density and location are shown by the color intensity of melanin and the regularity of the pigment network. When placed in the stratum corneum, it has a dark brown color and a welldefined network; when located in the lower layers of the epidermis, it has shades of light brown and an irregular network; and when positioned in the dermis, it has a blue or bluish-gray hue.

 

Management

A topical mixture of hydroquinone cream and avoidance of sun or estrogen exposure is the most effective therapy. Aside from avoiding sun exposure, stopping the use of high-SPF sunscreens (50 or above) can help prevent the development of melasma.

First-line therapy for melasma consists of effective topical therapies, primarily in the form of triple combinations (hydroquinone 4%, tretinoin 0.05%, and fluocinolone acetonide 0.01%); however, when triple combinations are unavailable or patients have hypersensitivity to them, dual ingredients or single agents should be considered.

Chemical peels and lasers can provide inconsistent outcomes and have side effects like as epidermal necrosis, postinflammatory hyperpigmentation, and hypertrophic scars. These procedures are only used as a last resort if topical medicine has failed. Chemical peels and lasers are typically safe in expert hands and can give effects faster than topical treatments.

 

Skin Peels

These procedures carry a risk of adverse outcomes. Peels use glycolic or salicylic acid-based compounds which may increase turnover of hyperpigmented keratinocytes. 

  • They are frequently started as a monthly therapy with low dosage formulae and advance to weekly treatments with larger doses.
  • For best effects, lightening chemicals are frequently used in combination with superficial peels.
  • Skin peels should be utilized only after a trial of treatment with at least one skin-lightening agent has been completed.
  • Close monitoring of skin depigmentation is required, and treatment should be discontinued if changes in pigmentation in the surrounding skin are seen.

 

Lasers

The efficiency of lasers in the treatment of melasma has been linked to unfavorable aesthetic outcomes. In situations of significant disease that is resistant to laser treatment, their usage should be evaluated, since it may potentially exacerbate the problem.

 

Corticosteroids

Corticosteroids can inhibit pigmentation by suppressing melanogenesis in a non-selective manner while simultaneously acting as an anti-inflammatory drug. When used alone, corticosteroids are unlikely to outperform depigmenting drugs. Despite their capacity to decrease melanogenesis on their own, the present evidence indicates that corticosteroids have not been shown to have long-term advantages in the treatment of melasma. Long-term steroid usage can also cause telangiectasias, acne, epidermal atrophy, striae, and hypopigmentation.

 

Retinoids

Topical retinoids have also been shown to be beneficial in the treatment of melasma, with the mechanism being that they promote keratinocyte turnover. In 1993, a small but important study found that tretinoin 0.1 percent cream may dramatically reduce objective colorimetry assessments of melasma pigmentation. Another research validated the efficacy of tretinoin 0.1 percent cream in the treatment of melasma in African-American individuals.

 

Prognosis

Melasma is not related with any mortality or morbidity. There have been no reports of malignant transformation or an increased risk of melanoma or other cancers. Melasma patients are thought to be less likely to develop melanoma.

Because no effective medication exists to remove dermal pigment, it may take longer to resolve than epidermal pigment. However, therapy should not be withheld only due to the presence of cutaneous pigment. The epidermis is the source of dermal pigment, and if epidermal melanogenesis is blocked over an extended length of time, dermal pigment will not refill and will gradually fade.

Resistant instances or recurrences of melasma are common and unavoidable if sun avoidance is not strictly adhered to.

 

Conclusion 

Melasma is a skin condition characterized by brown to gray-brown spots on the face. It usually appears on the cheekbones, chin, nasal bridge, forehead, and above the upper lip. It affects women more than males. Melasma is frequently caused during pregnancy. It also has an impact on women who use oral contraception and hormones.

Patients should avoid using cosmetics on sensitive skin on a regular basis. Rubbing triple creams vigorously on hyperpigmented regions may aggravate the condition. Prolonged exposure to creams containing powerful steroids can result in ochronosis. Melasma should be separated from post-inflammatory hyperpigmentation, actinic lichen planus, and exogenous ochronosis caused by hydroquinone.

Patient education should involve rigorous sun avoidance, since this is critical for melasma resolution and may prevent recurrence. Melasma patients should only use bleaching creams on dark spots. Resolution can take months with careful sun avoidance and topical bleaching lotions; patients should be instructed to expect slow but steady whitening.