This randomized, evaluator-blinded, split-face study evaluated whether adjunctive lesion-directed 308-nm excimer light improves inflammatory acne outcomes during oral azithromycin therapy. All participants received oral azithromycin 500 mg three times weekly for 8 weeks. One randomly allocated hemiface additionally received 308-nm excimer light twice weekly for 8 weeks, while the contralateral hemiface served as the azithromycin-only control. Papule and pustule counts and hemiface Investigator's Global Assessment were assessed through Week 8. Investigator's Global Assessment was reassessed at Week 16 after an 8-week treatment-free follow-up. We hypothesized that the excimer-treated hemiface would demonstrate greater reduction in total inflammatory-lesion count by Week 8.
Participants with bilateral inflammatory acne received oral azithromycin 500 mg after meals three times weekly for 8 weeks. One hemiface was randomized by coin toss to receive adjunctive lesion-directed 308-nm excimer light twice weekly for 8 weeks; the contralateral hemiface received no irradiation. The primary outcome was the within-participant between-side difference in change from baseline to Week 8 in total inflammatory lesion count, defined as papules plus pustules. Hemiface IGA was assessed through Week 16, following an 8-week treatment-free period.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
32
Monochromatic 308-nm excimer light was delivered using the KN-5000C device. Irradiation was lesion-directed and administered twice weekly for 8 weeks, with at least 48 hours between sessions, for a planned total of 16 sessions. Treatment began at 0.15 J/cm² and was increased according to erythema response and device dose settings, up to a maximum of 0.65 J/cm².
Description: Oral azithromycin 500 mg was administered after meals three times weekly for 8 weeks, corresponding to 24 scheduled doses.
Al-Azhar University Hospital
Damietta, Egypt
Change From Baseline in Total Inflammatory-Lesion Count at Week 8
Papules and pustules were counted separately for each hemiface by a blinded evaluator. Total inflammatory-lesion count was calculated as the sum of papules and pustules. Change was calculated as the baseline count minus the Week-8 count; positive values indicated improvement. The primary comparison was the within-participant difference in change between the excimer-treated and control hemifaces.
Time frame: Baseline and Week 8
Change From Baseline in Papule Count at Week 8
Papules were counted separately for each hemiface by a blinded evaluator. Change was calculated as the baseline count minus the Week-8 count; positive values indicated improvement.
Time frame: Baseline and Week 8
Change From Baseline in Pustule Count at Week 8
Pustules were counted separately for each hemiface by a blinded evaluator. Change was calculated as the baseline count minus the Week-8 count; positive values indicated improvement.
Time frame: Baseline and Week 8
Percentage Reduction in Total Inflammatory-Lesion Count at Week 8
Percentage reduction was calculated separately for each hemiface as 100 × (baseline total inflammatory-lesion count minus Week-8 total inflammatory-lesion count) divided by the baseline count. Higher percentages indicated greater improvement.
Time frame: Baseline and Week 8
Proportion of Hemifaces With at Least 50% Reduction in Total Inflammatory-Lesion Count
A responder was defined as a hemiface achieving at least a 50% reduction in total inflammatory-lesion count from baseline to Week 8.
Time frame: Baseline and Week 8
Proportion of Hemifaces With at Least 80% Reduction in Total Inflammatory-Lesion Count
A responder was defined as a hemiface achieving at least an 80% reduction in total inflammatory-lesion count from baseline to Week 8.
Time frame: Baseline and Week 8
Hemiface Investigator's Global Assessment Grade Over Time
Acne severity was graded separately for each hemiface by a blinded evaluator using a five-category Investigator's Global Assessment scale ranging from 0 to 4, where 0 indicated clear skin and 4 indicated severe acne. Lower grades indicated lower acne severity.
Time frame: Baseline, Week 4, Week 8, and Week 16
Participant Satisfaction With Each Hemiface
At Week 8, participants rated their satisfaction with each hemiface separately using an unvalidated numerical rating scale from 0 to 100. Higher scores indicated greater satisfaction.
Time frame: Week 8
Incidence of Solicited Local and Systemic Adverse Events
Solicited local events included procedural pain, erythema, irritation, burning, dryness, blistering, and pigmentary alteration. Solicited systemic symptoms potentially associated with azithromycin included gastrointestinal symptoms, hypersensitivity reactions, palpitations, dizziness or syncope, and symptoms suggestive of hepatic dysfunction. Severity was classified as absent, mild, moderate, or severe.
Time frame: From the first treatment through Week 16
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