Melasma

Acquired, chronic hypermelanosis characterized by symmetrical, irregularly bordered hyperpigmented macules and patches

Epidemiology

• Common in women of reproductive age

• Female : male ≈ 9 : 1

• More prevalent in Fitzpatrick skin types III–V

• Higher incidence in tropical regions

• Strong association with sun exposure, pregnancy, and hormonal factors

Aetiology

• Ultraviolet (UV) radiation (most important)

• Hormonal influences:
• Pregnancy (chloasma)
• Oral contraceptives

• Genetic predisposition

• Photosensitizing drugs and cosmetics

• Thyroid dysfunction (association)

Pathophysiology

• Hyperfunctional melanocytes with normal cell count

• Increased melanin synthesis and transfer

• UV exposure induces:
• ↑ α-MSH
• ↑ tyrosinase activity
• Dermal inflammation and vascular changes

Clinical presentation

• Symmetric, irregularly shaped brown to gray-brown macules/patches

• Well-defined but irregular borders

• No scaling, erythema, or symptoms

• Gradual onset, chronic course

• Exacerbated by sun exposure

Investigations

• Clinical diagnosis

• Wood’s lamp: helps determine pigment depth (limited in darker skin)

• Dermoscopy: reticulated brown pigmentation

• Biopsy: rarely required

Management

General Measures (Cornerstone)

• Strict photoprotection
• Broad-spectrum sunscreen (SPF ≥30–50)
• Physical blockers (zinc oxide, titanium dioxide)
• Protective clothing

Topical Therapy (First-line)

Procedural Therapy

• Chemical peels (glycolic, salicylic acid)

• Laser and light-based therapy (with caution)

• Microneedling (adjunctive)