How to apply azelaic acid for post-inflammatory hyperpigmentation (PIH)?

How to Apply Azelaic Acid for Post-Inflammatory Hyperpigmentation (PIH)

Azelaic acid should be applied twice daily as a thin film gently but thoroughly massaged into the affected areas with PIH, in the morning and evening, for optimal lightening effect on hyperpigmentation. 1

Formulation and Concentration

• Use prescription-strength azelaic acid (15-20% cream/gel) for most effective results
• Over-the-counter formulations (5-10%) may be less effective but can be used if prescription options are unavailable
• Apply to clean, dry skin before other skincare products

Application Technique

1. Cleanse the affected area with a gentle cleanser and pat dry
2. Apply a pea-sized amount of azelaic acid for each area of treatment
3. Gently massage in a thin layer until fully absorbed
4. Follow with moisturizer if skin feels dry
5. Apply sunscreen (SPF 30+) during daytime use

Treatment Duration and Expectations

• Initial improvement may be seen within 4-8 weeks
• Optimal results typically require 12 weeks or longer of consistent use 1
• Continue treatment until PIH has resolved, as azelaic acid has a good safety profile for extended use

Special Considerations for Skin of Color

Azelaic acid is particularly beneficial for patients with darker skin types due to its lightening effect on hyperpigmentation without causing irritation that could worsen PIH 1, 2. Recent data support the use of azelaic acid in skin of color as both safe and beneficial for treating both acne and subsequent PIH 2.

Mechanism of Action for PIH

Azelaic acid works through multiple mechanisms to address PIH:

• Inhibits tyrosinase, the key enzyme in melanin production 3
• Has anti-inflammatory properties that prevent further pigmentation
• Normalizes abnormal melanocyte function 4
• Promotes even distribution of melanin

Potential Side Effects and Management

• Common: mild transient burning, stinging, tingling, erythema, dryness
• Management strategies:
  • Start with evening-only application if irritation occurs
  • Apply moisturizer after azelaic acid application
  • Gradually increase to twice daily as tolerance improves
  • Avoid combining with other potentially irritating products initially

Combination Therapy

For enhanced efficacy, azelaic acid can be safely combined with:

• Topical retinoids (apply retinoid at night, azelaic acid in morning)
• Sunscreen (essential to prevent worsening of PIH)
• Moisturizers (to reduce potential irritation)

Precautions

• Avoid application near eyes, mouth, and mucous membranes
• Minimize sun exposure and always use sunscreen
• Safe for use during pregnancy (Category B) 1
• Not recommended for children under 12 years of age 1

Common Pitfalls to Avoid

1. Inconsistent application: Regular twice-daily application is necessary for optimal results
2. Inadequate sun protection: Failure to use sunscreen can worsen PIH despite treatment
3. Premature discontinuation: Results take time; continue treatment for at least 12 weeks
4. Using too much product: A pea-sized amount is sufficient for each treatment area
5. Combining with too many active ingredients: May increase irritation and potentially worsen PIH