Melasma

Introduction & Epidemiology - Mask of Mystery

• Definition: Acquired, often symmetric, macular hyperpigmentation on sun-exposed areas, primarily the face.
• Common Names: "Mask of pregnancy" (chloasma).
• Prevalence: Common, especially in Indian populations and individuals with Fitzpatrick skin types III-VI.
• Key Risk Factors (Multifactorial):
  • UV radiation (UVA, UVB, visible light) - most important avoidable factor.
  • Hormonal influences: Pregnancy (melasma gravidarum), OCPs, HRT.
  • Genetic predisposition & positive family history.
  • Photosensitizing medications (e.g., phenytoin, tetracyclines).
  • Thyroid dysfunction.
  • Certain cosmetics.

⭐ Melasma is significantly more common in women (approx. 9:1 female to male ratio) and individuals with Fitzpatrick skin types III-VI.

Pathophysiology - Pigment Party Crashers

• Primary Mechanism: Melanocyte hyperactivity (not proliferation) → ↑ melanogenesis & ↑ melanosome transfer to keratinocytes.
• Hormonal Influence: Estrogen, progesterone receptors, & MSH are key hormonal drivers.
• Signaling Pathways: Stem cell factor (SCF) & Wnt signaling implicated.
• UV Radiation: Major trigger; causes direct melanocyte stimulation, oxidative damage.
• Vascular & Inflammatory: ↑ VEGF, ↑ vascularity, & mast cell activation contribute.
• Genetic Predisposition: Inherited factors increase susceptibility.

⭐ Recent evidence highlights the role of vascular endothelial growth factor (VEGF) and increased vascularity in melasma pathogenesis, suggesting a link beyond just melanocytes.

Clinical Features & Diagnosis - Spot the Spots

• Symmetric, irregular, light-to-dark brown hyperpigmented macules and patches.
• Common patterns:
  • Centrofacial: Forehead, cheeks, nose, upper lip, chin.
  • Malar: Cheeks, nose.
  • Mandibular: Ramus of mandible.

• Wood's Lamp Examination:

• Differential Diagnosis: Post-inflammatory hyperpigmentation (PIH), Hori's nevus, Riehl's melanosis, drug-induced pigmentation, lentigines.

Management - Fading the Freckles

Cornerstone: Sun Protection

• Broad-spectrum (UVA/UVB, Visible Light, Infrared), SPF ≥30-50, PA+++. Daily, year-round.

Topical Therapy

• First-line:
  • Hydroquinone (2-4%, max 5%).
  • Triple Combination Cream (TCC): e.g., Kligman's/Modified. Components: Hydroquinone (HQ) + Tretinoin + Corticosteroid.
  • 📌 Mnemonic for Kligman's components: "Heavy Tan Sucks" (Hydroquinone, Tretinoin, Steroid).
  • Azelaic acid (15-20%).
• Other options: Kojic acid, Niacinamide, Cysteamine, Thiamidol.

⭐ The original Kligman's formula consists of hydroquinone 5%, tretinoin 0.1%, and dexamethasone 0.1%. Modified versions often use lower potency corticosteroids to reduce side effects.

Oral Agents

• Tranexamic acid (250mg BD).
• Others: Glutathione, Polypodium leucotomos extract.

Procedural Options (For refractory melasma)

• Chemical Peels: Superficial (e.g., glycolic acid, salicylic acid, TCA 10-20%).
• Lasers: Q-switched Nd:YAG (low fluence), Picosecond lasers. ⚠️ Use with caution due to Post-Inflammatory Hyperpigmentation (PIH) risk.
• Microneedling with topical application of depigmenting agents.

Stepwise Management Algorithm

Prevention & Prognosis - Sunscreen Savior

• Sun Protection (Year-Round):
  • Strict sun avoidance (even indoors, near windows).
  • Use broad-spectrum physical blockers: zinc oxide, titanium dioxide.
  • Iron oxide for visible light (VL) protection.
  • Wear wide-brimmed hats, sunglasses.
• Prognosis & Management:
  • High recurrence rate, especially with sun/hormonal triggers.
  • Chronic condition: requires long-term maintenance therapy & patient counseling.
  • Address modifiable risk factors (e.g., review OCPs).

⭐ Protection against visible light, particularly blue light, often through tinted sunscreens containing iron oxide, is increasingly recognized as crucial in melasma management due to its pigment-inducing effects.

High‑Yield Points - ⚡ Biggest Takeaways

• Melasma: common hyperpigmentation in women, linked to sun exposure & hormonal changes (e.g., pregnancy - chloasma).
• Symmetric, brownish macules/patches on face (centrofacial, malar, mandibular patterns).
• Wood's lamp differentiates epidermal (enhances) vs. dermal (no enhancement) pigment.
• Strict sun protection is cornerstone of management.
• Topicals: Hydroquinone (first-line), Kligman's formula (hydroquinone, tretinoin, steroid).
• Oral tranexamic acid for resistant cases.