Melasma is not a stain — it is a disease

Melasma presents as symmetrical brown-to-grey patches, typically across the cheeks, forehead, upper lip and chin. It is most common in women and in people with medium-to-dark skin phototypes, and it is provoked by ultraviolet and visible light, hormonal shifts and heat. For too long it has been treated as a blemish to be bleached away. It is better understood as a chronic disease of the pigment system.

What is actually going wrong

Melasma is not simply excess melanin sitting in the epidermis. Histology shows hyperactive, enlarged melanocytes transferring more pigment to surrounding keratinocytes, pigment that has dropped into the dermis, an abnormal increase in local blood vessels, and evidence of a damaged basement membrane and photo-aged skin. This is why it relapses: the machinery that overproduces pigment remains primed, and any trigger restarts it.

Consequences for treatment

If melasma is chronic, so is its management. Three principles follow. First, rigorous photoprotection — broad-spectrum sunscreen that also covers visible light — is the foundation; nothing else works durably without it. Second, active depigmentation is staged: hydroquinone remains the reference tyrosinase inhibitor, used in courses; for moderate-to-severe disease, a triple combination of a retinoid, a corticosteroid and hydroquinone attacks pigment production, inflammation and cell turnover at once. Third, long-term maintenance with gentler agents keeps disease quiescent between flares.

Managing expectations

Patients should be told plainly that melasma is controlled rather than cured, that visible improvement takes eight to twelve weeks, and that over-aggressive treatment can worsen pigmentation through irritation. The clinician's job is to set a realistic horizon and build a routine sustainable over years. Reframing melasma as a disease is not pedantry — it changes how it is treated, and how long the results last.