A randomized, double-blind, placebo-controlled clinical trial evaluating the role of systemic antihistamine therapy for the reduction of adverse effects associated with topical 5-aminolevulinic acid photodynamic therapy.

BACKGROUND AND OBJECTIVE: Following photodynamic therapy with 5-aminolevulinic acid (ALA-PDT), patients experience inflammation that may be partially attributable to H1 histamine receptor activation. The objective of this study was to evaluate the impact of antihistamines upon adverse effects following ALA-PDT.

STUDY DESIGN/MATERIALS AND METHODS: This was a randomized, placebo-controlled clinical trial conducted at a single study site. Twenty subjects with facial actinic keratoses were randomized to ALA-PDT plus cetirizine 10 mg (n = 10) versus placebo daily (n = 10) from 3 days pre-treatment to 3 days post-treatment for a total of 7 days. Signs of inflammation including erythema, edema, crusting, exudation, vesiculation, and erosion were evaluated on post-treatment days 1, 2, 3, 7, 30, 90, and 180. Actinic keratosis counts, investigator-rated Global Assessment Improvement Score (GAIS), healing, tolerability, and subject satisfaction were also assessed.

RESULTS: Erythema, edema, crusting, exudation, vesiculation, and erosion were not different between treatment groups. Actinic keratoses were significantly reduced by day 30 in both the antihistamine and placebo groups (P = 0.01 and 0.0009, respectively), with results sustained to day 60 in the antihistamine group and day 180 for the placebo group. However, counts were not different between groups at any time point. Investigator-rated GAIS, subject satisfaction, healing, and tolerability were similar between treatment groups.

CONCLUSION: This study suggests that while H1 antihistamines do not impair the efficacy of ALA-PDT, they also do not relieve post-treatment inflammation and discomfort. Lasers Surg. Med. 49:738-742, 2017. © 2017 Wiley Periodicals, Inc.