How does inflammation contribute to melasma?

What happens inside the skin?

Melasma patches contain immune cells, including T cells, macrophages and mast cells, alongside increased inflammatory signals. These findings suggest that immune activity helps sustain pigment production. The exact cause of melasma remains incompletely understood, and inflammation is one contributor alongside sunlight, hormones and genetic susceptibility.12

Ultraviolet exposure also changes the deeper skin. Ageing fibroblasts, cells that support skin structure, release signals that stimulate pigment cells. Changes to the skin barrier and pigment transport help pigment remain in the skin. Pigment gets most of the attention, but the surrounding skin cells are not merely office furniture.1

Sun exposure and hormonal changes can converge on shared pathways, creating oxidative stress, a form of cellular stress, and a persistent inflammatory environment. These interacting processes help explain why treating existing pigment does not necessarily remove the conditions that keep producing it.3

Does inflammation mean melasma should feel irritated?

No. Typical melasma causes flat patches of changed colour without itching or pain. Dark marks left after skin inflammation, called post inflammatory hyperpigmentation, are a separate condition that can resemble melasma. Persistent facial darkening deserves a medical assessment rather than a diagnosis based only on colour.456

What should you do differently?

• Protect against sunlight every day, throughout the year. Use broad spectrum SPF 50 or higher sunscreen containing iron oxides, which add protection against visible light. Wear a wide brimmed hat and use shade.
• Apply sunscreen before going outside and reapply at least every two hours outdoors. Reapply after swimming and towel drying.
• Stop using irritating skincare products and choose gentle formulas without fragrance. Irritation can worsen melasma.
• Discuss treatment with a dermatologist rather than escalating to stronger peels or lasers. These procedures can worsen pigmentation and require experienced practitioners.

Prescription combinations sometimes include hydroquinone, a retinoid and a steroid to reduce irritation. Use these under medical supervision, not as a reason to add a steroid yourself. Hydroquinone and retinoid creams should be avoided during pregnancy. Melasma responds slowly, particularly when longstanding, and pigmentation can return after sun exposure or stopping treatment.45

How do hormones contribute to melasma?

Increases in estrogen and progesterone during pregnancy are thought to trigger melasma. Hormonal contraception and hormone replacement therapy are also associated with it. Pregnancy related pigmentation often fades over several months after delivery, but can return during another pregnancy or with sun exposure.26

Can cosmetics cause melasma?

Some cosmetics and scented toiletries can cause a phototoxic reaction, meaning a damaging reaction involving light, that triggers melasma. Irritating products can also worsen existing patches. Cosmetic camouflage can hide the pigmentation, which is a more honest job description than making it disappear.45

Can medication cause melasma?

Possible triggers include seizure medicines, birth control pills and medicines that increase sensitivity to sunlight, including some antibiotics and blood pressure medicines. If patches appeared after starting medication, discuss that timing with the prescriber before changing treatment.2

How does genetics contribute to melasma?

Having a blood relative with melasma increases your risk. Genetic susceptibility interacts with environmental exposures rather than acting as a single explanation. Family history therefore helps explain susceptibility, while sunlight and hormonal changes help explain when patches develop or persist.23