Melasma

Specialty: Skin.

• chloasma
• pregnancy mask
• hyperchromic facial spots induced by hormones

Why it occurs

• Melanocytic hyperactivity induced by female sex hormones, estrogens and progesterone (common during pregnancy or use of oral contraceptives)
• Chronic exposure to ultraviolet radiation and visible light (direct stimulation of melanogenesis due to oxidative stress and cell damage)
• Individual family genetic predisposition (polygenic influence on melanin synthesis)
• Thyroid dysfunction or underlying endocrinological diseases
• Use of cosmetics or drugs with local photosensitizing properties.

Initial workup

Dermatological examination with Wood's light (to classify melasma according to the depth of the pigment deposit into epidermal, dermal or mixed) and dermoscopy. Endocrine analytical tests if there are symptoms of hormonal dysfunction: thyroid profile (TSH, T4), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and estradiol.

Standard management

• Hydroquinone 2% or 4% in cream — first-line depigmentant that competitively inhibits the tyrosinase enzyme, blocking melanin synthesis; strict nocturnal application with rest periods to avoid exogenous ochronosis
• 15% or 20% azelaic acid in gel or cream — selective inhibitor of hyperactive melanocytes with anti-inflammatory properties
• Modified Kligman formula — association of hydroquinone, tretinoin and a mild corticosteroid such as hydrocortisone; the gold standard under medical supervision
• Tranexamic acid (plasminogen pathway inhibitor with melanogenesis-reducing effect, administered orally at low doses of 250 mg every 12 hours under strict medical indication).