Azelaic Acid 20% vs Hydroquinone 4% in Epidermal Melasma

This randomized controlled trial was conducted in the Dermatology Department of Gujranwala Medical College Hospital, Gujranwala, from 4 May 2025 to 3 August 2025. The study was designed to compare the efficacy and safety of topical 20% azelaic acid and 4% hydroquinone in the treatment of epidermal melasma.

A total of 146 patients with clinically diagnosed epidermal melasma confirmed by Wood's lamp examination were enrolled. Patients of any age and gender were eligible. Exclusion criteria included dermal or mixed-type melasma, active skin infections, history of keloid formation, recent use of other depigmenting agents, photosensitive disorders, pregnancy or lactation, and refusal to provide written informed consent.

After obtaining informed consent, participants were randomly assigned to one of two treatment groups in a parallel design. Group A received topical azelaic acid 20%, and Group B received topical hydroquinone 4%. Participants were blinded to their treatment allocation, while treating clinicians and research staff were aware of the assigned treatment. The statistician analyzing the data was blinded to group allocation.

Both treatments were administered for a duration of 12 weeks. Participants were evaluated at baseline and then monthly. All participants were advised to use broad-spectrum sunscreen throughout the study period. Treatment compliance and adverse effects were assessed at each follow-up visit. Any adverse effects such as erythema, burning, itching, or dryness were managed with supportive care, including emollients or antihistamines if required.

The primary outcome measure was treatment efficacy, assessed by the change in Melasma Area and Severity Index (MASI) score from baseline to the end of the 12-week treatment period. Secondary outcomes included the rate of improvement over time and the safety and tolerability of both treatments.

MASI scoring was performed using a standardized method that evaluates the area of involvement, darkness, and homogeneity of melasma across four facial regions: forehead, right malar region, left malar region, and chin. Clinical photographs were also obtained to support clinical assessment.

Data were analyzed using statistical software. Quantitative variables were summarized as means and standard deviations, and qualitative variables as frequencies and percentages. Between-group comparisons of MASI scores were performed using independent-samples t-tests, with a p-value of less than 0.05 considered statistically significant.

Inclusion criteria

• Patients with clinically diagnosed epidermal melasma confirmed by Wood's lamp examination
• Male or female participants of any age
• Willingness to provide written informed consent
• Ability to comply with study procedures and follow-up visits

Exclusion criteria

- Dermal or mixed-type melasma

• Active cutaneous or facial skin infection
• History of keloid formation
• Recent use of other topical or systemic depigmenting agents
• Presence of photosensitive disorders
• Pregnancy or lactation
• Refusal or inability to provide written informed consent