Melasma

Melasma is a common, acquired hyperpigmentation disorder characterized by symmetric brown or gray-brown patches on sun-exposed areas of the face.

• Presentation: Macular (flat) patches primarily on the cheeks (malar), forehead, upper lip, nose, and chin (centrofacial pattern). It occurs far more frequently in women and in individuals with darker skin types (Fitzpatrick skin types III-VI).
• Primary Triggers:
  • Ultraviolet (UV) & Visible Light: Sunlight stimulates melanocytes to produce more pigment. High-energy visible (HEV) light (blue light) also triggers pigmenatation, particularly in darker skin.
  • Hormonal Fluctuations: Strongly associated with pregnancy (often called the "mask of pregnancy" or chloasma), oral contraceptives, and hormone replacement therapy.

🔍 Melasma Depth & Wood's Lamp Examination

To determine the clinical prognosis and select appropriate treatments, dermatologists classify melasma based on the depth of melanin pigment using a Wood's lamp (black light) examination:

• Epidermal Melasma: Melanin is deposited in the superficial layers of the skin (epidermis). Under Wood's lamp, the patches become **accentuated (appear darker)**. This type has the best prognosis and responds well to topical tyrosinase inhibitors.
• Dermal Melasma: Melanin has dropped into the deeper skin layer (dermis) and is engulfed by scavenger cells (melanophages). Under Wood's lamp, the patches do **not accentuate (appear unchanged)**. Dermal melasma is highly resistant to standard topical treatments and often requires oral medications or specialized lasers.
• Mixed Melasma: The most common clinical presentation, featuring pigment deposition in both the epidermal and dermal layers. Under Wood's lamp, some areas of the patches become darker while other areas remain unchanged.

Topical therapy is the cornerstone of melasma management, designed to suppress melanin synthesis pathways.

Standard Topicals

• Hydroquinone (2% - 4%): The gold standard tyrosinase inhibitor that blocks the conversion of tyrosine to melanin. It is typically used in cycles (up to 3-4 months) to avoid the rare risk of ochronosis (skin darkening).
• Triple Combination Cream (Kligman's Formula): A highly effective synergistic cream containing Hydroquinone, a corticosteroid (to reduce inflammation), and Tretinoin (to increase cell turnover).
• Azelaic Acid (15% - 20%) & Kojic Acid: Safe, non-hydroquinone alternatives that selectively target hyperactive melanocytes.

For refractory or severe cases, advanced systemic agents and physical solar blockers provide crucial support.

• Oral Tranexamic Acid (TXA): Low-dose oral TXA (typically 250mg twice daily) has emerged as a powerful systemic treatment. It inhibits plasminogen activation, reducing melanocyte-stimulating factors induced by UV light.
• Iron Oxide Sunscreens: Standard chemical or zinc sunscreens block UV light, but do not block high-energy visible (blue) light. Sunscreens containing **iron oxide** are mandatory for melasma patients to block blue light from the sun and digital screens.

📊 Disease Severity & The MASI Score

Dermatologists evaluate the severity of melasma using the **Melasma Area and Severity Index (MASI)**. The score ranges from 0 to 48, calculated by dividing the face into four regions (forehead, right malar, left malar, and chin):

• Calculation Factors: For each of the four regions, the score accounts for:
  • Area of Involvement (A): Estimated percentage of the area affected (graded 0 to 6).
  • Darkness (D): The intensity of hyperpigmentation compared to normal skin (graded 0 to 4).
  • Homogeneity (H): The uniformity of the pigmentation (graded 0 to 4).
• Clinical Utility: MASI scores are tracked in clinical trials to measure the percentage reduction in pigmentation over time (e.g. MASI 50 or MASI 75).

Clinical trials are currently investigating oral TXA safety, novel non-hydroquinone topical molecules, and picosecond laser parameter protocols.

If you have recently been diagnosed with Melasma, follow these steps to manage pigmentation:

1. Switch to a Tinted Mineral Sunscreen: Ensure your daily sunscreen contains iron oxides (look for "tinted" zinc oxide sunscreens) to protect against both UV and visible blue light.
2. Review Hormone Medications: Discuss with your doctor if oral contraceptives or hormone therapies are contributing to the pigmentation and if non-hormonal alternatives are suitable.
3. Avoid Skin Irritation: Harsh scrubs, waxing, or irritating skincare products can trigger post-inflammatory hyperpigmentation, worsening melasma. Use only gentle cleansers.
4. Plan a Rotational Routine: If using hydroquinone-based creams, follow a strict schedule (e.g., 3 months on, 3 months off) under dermatological supervision to ensure safety.

Q: Does melasma go away after pregnancy?
A: In many women, melasma that develops during pregnancy resolves or fades significantly within several months after delivery, although it can recur in subsequent pregnancies or with contraceptive use.

Q: Can computers or phone screens make my melasma worse?
A: Yes. Digital screens emit high-energy visible (blue) light, which has been shown to stimulate melanocytes and worsen pigmentation in individuals with darker skin types. Wearing tinted sunscreens containing iron oxides helps protect against digital light.