Skin Care Education

Melasma

A hormonally driven pigmentation condition causing diffuse, symmetrically distributed brown or grey-brown patches on the face. More persistent and more prone to recurrence than other forms of hyperpigmentation.

What Is Melasma?

Melasma is a form of acquired hyperpigmentation characterised by diffuse, symmetrically distributed patches of brown or grey-brown discolouration that most commonly appear across the cheeks, forehead, bridge of the nose, upper lip, and chin. It is one of the most prevalent pigmentation conditions worldwide, affecting people across many skin tones and ethnicities, and is strongly associated with hormonal activity, which distinguishes it mechanistically from other common forms of pigmentation such as sun spots and post-inflammatory marks.

The condition is significantly more common in women than men, reflecting the central role of female sex hormones in its pathogenesis. It frequently develops during pregnancy, where it has historically been referred to as the mask of pregnancy or chloasma, and is also commonly triggered or worsened by hormonal contraceptives and hormone replacement therapy. When melasma occurs in men, it is often associated with UV exposure in genetically susceptible individuals rather than hormonal drivers.

What distinguishes melasma from other forms of hyperpigmentation is not only its hormonal component but its behaviour: it is significantly more persistent, more prone to recurrence after treatment, and can involve pigment deposited at multiple depths within the skin. These characteristics make it one of the more challenging pigmentation conditions to manage effectively and explain why long-term maintenance rather than a single course of treatment is typically the appropriate framework.

Causes and Contributing Factors

Factor	Description
Hormonal activity	The primary driver of melasma. Oestrogen and progesterone stimulate melanocytes to produce excess melanin in susceptible individuals. Pregnancy, combined oral contraceptives, progestogen-only contraceptives, and hormone replacement therapy are all established hormonal triggers. The mechanism by which sex hormones stimulate melanocyte activity is not completely understood but the clinical association is well established.
UV exposure	The most consistent external trigger for melasma flares and the most important factor in preventing recurrence after treatment. Even brief, low-level UV exposure can activate melanocytes in affected areas and rapidly darken treated or controlled melasma. UV exposure acts synergistically with hormonal activity to worsen the condition.
Infrared heat	Beyond UV radiation, infrared radiation, the heat component of sunlight and other heat sources, has been shown to independently stimulate melanocyte activity and trigger melasma flares. This means that even in individuals who are protected from UV, exposure to significant heat from sunlight or other sources can worsen or maintain melasma.
Genetics	Melasma has a strong hereditary component. It is significantly more common in individuals with a family history of the condition. Skin tone is also a significant genetic factor: melasma is substantially more prevalent and typically more pronounced in medium to deeper skin tones, which have higher baseline melanocyte density and activity.
Thyroid disorders	Thyroid dysfunction, particularly hypothyroidism, has been associated with melasma in several studies. The mechanism is thought to involve thyroid hormone effects on melanocyte stimulating hormone and related pathways, though the relationship is not yet fully characterised.
Certain skincare products and treatments	Products or procedures that cause skin irritation or inflammation can worsen melasma by stimulating melanocyte activity in affected areas. Some treatments that are effective for other forms of hyperpigmentation carry a risk of worsening melasma through their heat or inflammatory effects if not carefully selected and calibrated for melasma specifically.
Visible light	Emerging research suggests that visible light, particularly high-energy visible light from the blue end of the spectrum, may also stimulate melanocyte activity and contribute to melasma in darker skin tones. This is an area of ongoing research with clinical relevance for those who find that standard UV protection alone does not fully control their melasma.

Frequently Asked Questions: Melasma

Several features of melasma combine to make it significantly more challenging to manage than sun spots or post-inflammatory marks. First, its primary driver is hormonal activity, which continues regardless of any topical or professional treatment applied to the skin. Second, melasma frequently involves pigment deposited at multiple levels within the skin, including in the deeper dermis as well as the superficial epidermis, making it harder to reach and clear comprehensively. Third, it is extremely sensitive to UV and heat triggers, meaning that even careful management can be undermined by relatively brief sun or heat exposure. Fourth, some treatment approaches that would be effective for superficial pigmentation carry a risk of worsening melasma through inflammatory or heat-related stimulation of melanocytes. These factors together mean that melasma management requires a more sustained, multifaceted, and careful approach than other pigmentation conditions.

In some cases, particularly when melasma was triggered by a temporary hormonal change such as pregnancy or a contraceptive that has since been discontinued, it may fade significantly without active management. However, this natural resolution is not universal and can take months to years. In many individuals, particularly those with persistent hormonal exposure, genetic susceptibility, or ongoing UV exposure, melasma will not resolve spontaneously and will persist or deepen without consistent management. Even when melasma does fade, the underlying tendency to develop it remains, and it can return readily with hormonal changes or UV exposure.

Sun protection is the single most important component of melasma management and is considered non-negotiable in any effective approach. Without consistent, broad-spectrum UV protection, melasma will continue to be stimulated and will return after any treatment. However, SPF alone is often insufficient for full melasma control for two reasons. First, standard SPF products protect primarily against UVA and UVB but not against infrared heat or visible light, which can also trigger melanocyte activity in melasma. Second, preventing new stimulation does not clear existing pigment that has already been deposited. Effective management typically combines diligent UV and heat protection with targeted approaches to address existing pigmentation.

Yes, though it is significantly less common in men than women. The strong hormonal component of melasma means that it predominantly affects those with female sex hormone exposure. When melasma occurs in men, it tends to be associated primarily with significant UV exposure in genetically susceptible individuals rather than with hormonal drivers. The same principles of UV protection and management apply regardless of sex, though the underlying trigger profile may differ.