Efficacy of Combined Oral Isotretinoin and Desloratadine or Levocetirizine vs. Isotretinoin Monotherapy in Treating Acne Vulgaris: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background/Objectives: Acne vulgaris is a widespread, chronic inflammatory skin condition that significantly impacts patients’ quality of life. Although oral isotretinoin remains the most effective treatment, recent evidence suggests that H1-antihistamines such as desloratadine and levocetirizine may enhance acne therapy. This study assesses whether combining H1-antihistamines to isotretinoin enhances treatment efficacy in acne vulgaris compared to isotretinoin alone. Methods: Our analysis included 10 randomized controlled trials involving 675 patients collectively, predominantly from Asia and the Middle East. Data were extracted by two independent reviewers, with discrepancies resolved by a third. Risk of bias was assessed using the Cochrane RoB 2 tool. Analyses were performed using RevMan 5.4 with random-effects models, and heterogeneity was evaluated via I2 and Q tests. Sensitivity analyses were conducted to assess result robustness. Results: Combination therapy with isotretinoin and desloratadine showed a significantly greater reduction in GAGS (Global Acne Grading Scale) score by week 12 (p < 0.00001; MD 2.68, 95% CI 1.60 to 3.75; I2 = 0%) while earlier timepoints showed non-significant or borderline results. For inflammatory lesions, significant improvements with desloratadine emerged at weeks 4, 8, and 12 after excluding an influential outlier, with low heterogeneity and consistent direction of effect. Non-inflammatory lesions did not differ significantly at weeks 4 or 8. At week 12, a significant reduction was seen in the desloratadine subgroup (OR 2.61, p = 0.003, I2 = 11%) and in overall pooled analysis (OR 2.77, p < 0.0001, I2 = 2%). Among side effects, acne flare-ups, pruritus, and cheilitis were significantly reduced in the desloratadine group, as well as in pooled analysis. Xerosis did not consistently differ between groups. Overall, desloratadine improved tolerability and reduced mucocutaneous adverse events more than levocetirizine. Conclusions: Current evidence suggests that combining oral antihistamines with isotretinoin may offer therapeutic benefits in acne management, particularly in enhancing tolerability and potentially improving clinical outcomes, as reflected by significant reductions in GAGS scores and mucocutaneous adverse effects such as cheilitis, pruritus, and acne flare-ups.