What is melasma?

Melasma: Definition, Causes, and Treatment

Melasma is a common acquired skin condition characterized by symmetrical brown or gray-brown patches primarily on the face, caused by excessive melanin production, most prevalent in females and darker skin types, and triggered by UV exposure and hormonal influences. 1

Clinical Characteristics

• Appearance: Symmetrical gray-brown or brown patches with irregular borders 1, 2
• Distribution: Primarily affects sun-exposed areas, especially the face 2
• Patterns:
  • Centrofacial (most common, 55.44%): affects forehead, cheeks, upper lip, nose, and chin 3
  • Malar: affects cheeks and nose
  • Mandibular: affects jawline 3
• Classification by depth (determined by Wood's lamp examination):
  • Epidermal (21.47%)
  • Dermal (54.48%, most common)
  • Mixed (24.03%) 3

Epidemiology

• Gender: Female predominance with a female-to-male ratio of approximately 4:1 3
• Age: Mean age of onset around 30 years 3
• Skin types: More prevalent in individuals with Fitzpatrick skin types III-V (darker skin) 2
• Prevalence: Ranges widely from 1-50% depending on the ethnic population and geographic region 4
• Genetic predisposition: Positive family history observed in approximately 33% of patients 3

Etiology and Pathogenesis

Multiple factors contribute to melasma development:

• UV radiation exposure: Primary trigger, exacerbates condition in 55% of patients 3
• Hormonal factors:
  • Pregnancy (commonly called "mask of pregnancy") 5
  • Oral contraceptive use 3
  • Hormonal imbalances 5
• Genetic predisposition: Strong familial tendency 3, 2
• Other factors:
  • Thyroid dysfunction 6
  • Inflammatory processes of the skin 2
  • Use of cosmetics, steroids, and photosensitizing drugs 2

Histopathology

• Increased epidermal and/or dermal melanin pigmentation
• Enlarged melanocytes
• Increased melanosomes
• Solar elastosis
• Dermal blood vessels
• Occasionally perivascular lymphohistiocytic infiltrates 4

Diagnosis

Diagnosis is primarily clinical, based on:

• Visual examination using the "ABCD" rule (Asymmetry, Border irregularity, Color heterogeneity, Dynamics) 1
• Wood's lamp examination to determine depth of pigmentation (epidermal, dermal, or mixed) 3
• Melasma Area and Severity Index (MASI) or Modified Melasma Area and Severity Index (mMASI) to assess severity and monitor treatment response 1, 7

Treatment Options

First-Line Therapy

• Topical treatments:
  • Hydroquinone 4% cream: FDA-approved for gradual bleaching of hyperpigmented skin conditions including melasma 8, 7
  • Triple combination cream: Containing hydroquinone, tretinoin, and corticosteroid 7
  • Strict sun protection: Broad-spectrum SPF 70 or higher sunscreen is essential 7

Second-Line Options

• Oral medications:

  • Tranexamic acid (250 mg twice daily): For moderate to severe cases resistant to topical therapy 7

• Procedural treatments (when topical treatments fail after 8-12 weeks):

  • Chemical peels: Glycolic acid, salicylic acid 7
  • Laser therapy: 1,064-nm Q-switched Nd:YAG laser with ultrasonic application of vitamin C has shown promising results 5
  • Autologous platelet concentrates (APCs): Emerging treatment showing efficacy and safety 1

Management Guidelines

1. Initial assessment:

   • Determine skin phototype (Fitzpatrick scale)
   • Identify underlying causes
   • Assess depth of pigmentation 7

2. Treatment approach:

   • Begin with topical hydroquinone 4% cream as first-line therapy 7, 8
   • Add retinoids at night for enhanced results 7
   • Ensure strict sun protection with broad-spectrum SPF 70+ 7

3. Monitoring:

   • Evaluate response every 4-6 weeks using standardized photography and MASI score 7
   • Adjust treatment if no improvement after 8-12 weeks 7
   • Hydroquinone can be used safely for up to 6 months 7

4. Maintenance therapy:

   • Continue sun protection indefinitely 7
   • Consider hydroquinone-free agents for maintenance 7

Important Considerations and Pitfalls

• Sun protection: Inadequate sun protection is the most common reason for treatment failure and recurrence 7
• Overuse of hydroquinone: Can lead to exogenous ochronosis with prolonged use beyond 6 months 7
• Aggressive treatments: High-concentration peels or laser treatments can worsen hyperpigmentation 7
• Hormonal factors: Oral contraceptives or hormone replacement can impact treatment outcomes 7
• Early discontinuation: Stopping treatment too early can lead to recurrence 7
• Chronic condition: Melasma should be managed as a chronic condition with regular follow-ups 1