Understanding Melasma: What It Is, Why It Happens, and What the Science Says

Irregular patches of brown or grey-brown discoloration appearing on the face — particularly across the cheeks, forehead, upper lip, or chin — are often associated with one of the most commonly studied pigmentation conditions in dermatology: melasma.

Melasma is described in medical literature as an acquired hyperpigmentation disorder. It typically appears symmetrically on areas of the skin that receive the most sun exposure, and while it can occur in anyone, it is observed more frequently in women and in individuals with medium to darker skin tones.

This article summarises general educational information drawn from published dermatology references. It is not medical advice. Anyone with concerns about a skin condition should speak with a qualified healthcare professional.

What Melasma Looks Like

Melasma generally presents as flat patches of pigmentation that are darker than the surrounding skin. The patches usually have an irregular border and tend to be symmetrical — meaning if a patch appears on one cheek, a similar one often appears on the other.

Dermatologists generally describe three common distribution patterns on the face:

• Centrofacial pattern. Affects the centre of the face — forehead, cheeks, nose, upper lip, and chin. This is the most common pattern.
• Malar pattern. Limited to the cheeks and nose.
• Mandibular pattern. Appears along the jawline.

Less commonly, melasma can also appear on the forearms, neck, or upper chest — areas that also receive regular sun exposure.

What the Research Says About Causes

The exact mechanism behind melasma is still being studied, but researchers have identified several factors that appear to play a role in its development.

Sun exposure (UV and visible light)

Ultraviolet (UV) radiation is one of the most consistently identified triggers. Studies have also pointed to visible light — particularly high-energy visible (HEV) light — as a contributor in individuals with darker skin tones. Sun exposure appears to stimulate melanocytes, the cells responsible for producing pigment.

Hormonal influences

Melasma is sometimes referred to as "the mask of pregnancy" (chloasma) because of how frequently it appears during pregnancy. Hormonal factors — including those linked to pregnancy, oral contraceptives, and hormone replacement therapy — are commonly cited in the literature as influential.

Genetic predisposition

A family history of melasma is common among those who develop it. Studies suggest that genetic factors influence both the likelihood of developing the condition and how it may respond over time.

Other reported factors

Researchers have also examined associations with thyroid function, certain medications, scented skin products, and inflammation from cosmetic procedures. These are areas of ongoing research and not universal causes.

Who Tends to Be Affected

Available data suggests melasma is significantly more common in women than men, with most cases appearing between the ages of 20 and 50. It is more frequently observed in individuals with Fitzpatrick skin types III through V — that is, medium to medium-dark complexions — though it can affect any skin tone.

Geographic studies indicate higher reported prevalence in regions with strong year-round sun exposure, which aligns with the role UV light is thought to play in its development.

General Lifestyle Considerations Discussed in the Literature

Many dermatology references discuss general considerations that individuals with melasma may wish to be aware of. None of these constitute treatment — they reflect themes commonly highlighted in published patient education materials.

• Daily sun protection. Broad-spectrum sun protection is the most consistently emphasised topic across guidelines. Recommendations typically reference daily use regardless of weather or season.
• Physical barriers. Wide-brimmed hats and protective clothing are commonly mentioned alongside sunscreen.
• Awareness of trigger windows. Some individuals report that pigmentation becomes more prominent after periods of increased sun exposure or during hormonal changes.
• Gentle skin care routines. Patient education materials commonly suggest avoiding harsh, fragranced, or irritating products on affected areas.

These are general points discussed in educational sources — not a treatment plan. A dermatologist can assess an individual's specific situation and discuss appropriate next steps.

When People Typically Consult a Dermatologist

Most published guidance suggests consulting a qualified healthcare professional may be appropriate in situations such as:

• There is uncertainty about whether a patch of pigmentation is melasma or something else.
• A patch of pigmentation appears to be changing in size, colour, or texture.
• A person would like to understand what management approaches are available in their region.
• The appearance of the skin is causing day-to-day concern for the individual.

A dermatologist can examine the skin directly — sometimes using a Wood's lamp or other diagnostic tools — to confirm what is being observed and discuss what is appropriate for each individual.

What This Article Is — and Isn't

This piece is part of Health Report Pro's educational library, which summarises general information about commonly discussed health and skin topics. It is intended for adults curious about a topic they may have come across, not as a substitute for personalised medical advice.

Every article we publish goes through editorial review for clarity and is based on publicly available references.