Evaluation of the effectiveness of intense pulse light vs topical benzoyl peroxide 2.5% gel in patients of inflammatory acne receiving oral azithromycin pulse therapy: a randomized control trial

INTRODUCTION

A precise definition of acne vulgaris is difficult to frame. It can be defined as a chronic, self-limiting, inflammatory disease of the pilosebaceous unit, manifesting generally in adolescence with pleomorphic lesions like comedones, papules, nodules and cysts. Acne vulgaris is a very common condition affecting adolescents and young adults.^1,2 Topical treatments for acne vulgaris include retinoids, benzoyl peroxide and antibiotics (clindamycin, nadifloxacin, erythromycin, dapsone). Other widely used agents are azelaic acid, salicylic acid, sulfur, alpha hydroxyl acids (glycolic, salicylic) and picolinic acid, offering diverse therapeutic options. Systemic therapy for acne includes antibiotics such as tetracycline, doxycycline and azithromycin, along with hormonal treatments like estrogen and antiandrogens. Oral isotretinoin is used for severe cases, while physical modalities like chemical peeling, laser therapy and acne surgery help in resistant cases. However, treatment outcomes vary due to resistance and poor compliance, leading to complications like scarring, psychological distress and reduced self-esteem, necessitating effective interventions.^3,4

Acne vulgaris is a chronic inflammatory disease affecting adolescents and young adults worldwide, significantly impacting social and psychological well-being. Though considered a physiological condition, its inflammatory nature and facial disfigurement make it a clinically significant disorder. The prevalence is high across all races, with urban populations and smokers experiencing more severe cases in India.^5,6

Traditional topical and systemic treatments often lead to adverse effects and resistance, prompting increased interest in light-based therapies, particularly Intense Pulsed Light (IPL), which has shown promise in reducing inflammatory acne lesions.^7-10 However, comparative studies between IPL and benzoyl peroxide 2.5% gel remain insufficient, warranting further investigation. This study evaluates IPL’s effectiveness against benzoyl peroxide 2.5% gel in inflammatory acne treatment.

METHODS

Following ethical approval, this randomized controlled trial was conducted at the Department of Dermatology, Venerology and Leprosy of a tertiary care center, Akola, between January 2020 to June 2021. A total of 60 clinically diagnosed inflammatory acne patients were enrolled based on specific inclusion and exclusion criteria, with written informed consent obtained from each participant. Patients were randomly allocated into two treatment groups using a random number table method: Group A, which received Intense Pulsed Light (IPL) therapy and Group B, which was treated with topical benzoyl peroxide (2.5%) Gel.

Both groups were administered oral azithromycin (250 mg) thrice weekly for two months as adjunct therapy. Baseline assessments included lesion count, erythema grading and the Michaelson Severity Index (MSI) score, alongside photographic analysis. IPL patients underwent four biweekly sessions, with fluence adjusted based on Fitzpatrick skin type, while benzoyl peroxide was applied nightly. Follow-ups occurred every two weeks, where clinical assessments, photographic evaluations and patient self-assessment ratings were documented. Statistical analysis was performed using SPSS 26, utilizing paired and unpaired t-tests to assess the treatment efficacy and compare outcomes. This methodological approach ensured a scientific and valid comparison between IPL and benzoyl peroxide for treating inflammatory acne, aiming to establish an optimal therapeutic strategy for acne management.

RESULTS

Demographic findings

This study involved 60 patients, evenly divided into Group A (IPL therapy) and Group B (Topical Benzoyl Peroxide 2.5% Gel) (Table 1). Most participants were 21–25 years old (68%), with a mean age at presentation of 23.30±3.553 years and a mean age of acne onset at 17.68±1.823 years. The average acne duration was 2.90±1.613 years, indicating chronic cases.

The patient distribution reflected a male predominance (82%), with 84% being unemployed. This suggests a significant impact of acne on young individuals entering adulthood and the workforce. Additionally, 62% were urban residents, reinforcing environmental and lifestyle factors contributing to acne severity.

Acne severity and treatment response

Acne severity was assessed using the Michaelson Severity Index (MSI). The majority of patients had moderate acne (MSI score: 21–30), accounting for 62% of cases, while 16% had severe acne with an MSI score above 30 (Table 2).

Following treatment, IPL therapy demonstrated greater improvement in acne severity compared to benzoyl peroxide gel. At the fourth sitting, 41.6% of IPL patients showed moderate resolution and 16.6% showed good resolution, compared to 20% moderate resolution and 12% good resolution in the benzoyl peroxide group (Table 3). The photographic assessment by independent observers confirmed these results, showing higher rates of lesion improvement in IPL patients (Table 4).

Statistical analysis and adverse effects

Paired t-tests indicated significant reductions in MSI scores for both groups (p<0.0001), confirming the effectiveness of both treatments (Table 5, Table 6). However, IPL demonstrated greater lesion reduction with higher improvements in subjective and photographic analysis. Adverse effects were mild and transient, with IPL causing more cases of transient erythema (32%) compared to benzoyl peroxide (16%). However, no persistent erythema, blisters, edema or pigmentation were observed, reinforcing IPL as a safe treatment modality with a favorable tolerance profile.

*Percentage calculated column-wise. Most patients are aged 21-25 years, followed by smaller proportions in younger and older age groups. Both treatment groups are evenly distributed, ensuring balanced age representation.

*Percentage calculated column-wise. The 21-30 MSI score range has the highest number of patients, comprising 62% of the total sample, followed by 10-20 and 31-40 severity categories. Both treatment groups have a comparable distribution across severity levels, ensuring a balanced assessment of intervention effectiveness.

*Percentage calculated column-wise. At the 2nd sitting follow-up, Group B showed more mild resolution, while Group A had higher moderate resolution. By the 4th sitting, both groups improved, with Group A showing more moderate and good resolution, though differences were not statistically significant.

*Percentage calculated column-wise. At the 2nd sitting, most patients showed mild resolution, with Group A having more moderate cases. By the 4th sitting, Group A saw increased moderate resolution, while Group B retained a higher mild resolution.

The paired t-test shows significant improvement across all parameters, with subjective and photographic analysis indicating better resolution by the 4th sitting. The MSI score also demonstrates a notable reduction over time, confirming the effectiveness of IPL treatment (p<0.0001).

The paired t-test indicates significant improvement with Topical 2.5% BPO Gel, showing better subjective and photographic resolution by the 4th sitting. The MSI score also declines over time, confirming its effectiveness (p<0.0001).

DISCUSSION

Acne vulgaris, a chronic inflammatory disease of the pilosebaceous unit, significantly affects adolescents and young adults, causing physical and psychological distress. This study compared the efficacy of Intense Pulsed Light (IPL) therapy combined with azithromycin pulse therapy versus topical benzoyl peroxide (BPO) 2.5% gel with azithromycin pulse therapy for managing inflammatory acne.

Patient characteristics

A total of 60 patients with inflammatory acne were included, equally randomized into two groups. Most participants (68%) were aged 21–25 years, with a mean age of 23.30±3.553 years at presentation. Acne onset occurred at a mean age of 17.68±1.823 years, with an average duration of 2.9±1.613 years. Most participants were male (82%) and unmarried (96%). At baseline, 62% of patients had MSI scores between 21–30, indicating moderate disease severity.

Efficacy of treatment modalities

IPL therapy (Group A)

Patients receiving IPL showed a reduction in MSI scores from 25.96±7.050 at baseline to 22.44±6.138 after four sittings. Subjective analysis revealed mild or moderate resolution in 83.2% of patients and good resolution in 16.6%. Observer-based photographic analysis supported these findings, noting mild and moderate resolution in 50% of cases each. Prior studies by Elman et al and Dierickx also reported IPL's effectiveness, with lesion clearance rates of 72% for non-inflammatory and 50% for inflammatory acne.^11,12

BPO 2.5% gel therapy (Group B)

Topical BPO gel reduced MSI scores from 25.24±5.372 at baseline to 21.83±5.172 after four sittings. Mild resolution was reported by 68% of patients, moderate resolution by 20% and good resolution by 12% in subjective analysis. Photographic evaluation noted mild resolution in 72% and moderate resolution in 24%. Benzoyl peroxide's antimicrobial and anti-inflammatory properties explain these results.^13,14

Comparative analysis

Statistical tests revealed no significant difference between the two modalities in terms of overall efficacy (p>0.05). While IPL demonstrated slightly earlier improvement, BPO gel was equally effective over time.

Safety profile

Transient erythema was the most common adverse event, reported in 32% of IPL patients compared to 16% of BPO gel patients. No persistent erythema or severe side effects were observed.

Both Intense Pulsed Light (IPL) therapy and topical benzoyl peroxide (BPO) 2.5% gel combined with azithromycin pulse therapy demonstrated comparable efficacy in reducing inflammatory acne severity, as reflected by significant reductions in Michaelson Severity Index scores. While IPL exhibited slightly earlier clinical improvements, the difference was not statistically significant and both modalities showed similar resolution outcomes over the treatment period. The safety profiles of both therapies were favorable, with transient erythema reported more frequently in the IPL group. IPL presents a viable non-topical alternative, particularly for patients intolerant to benzoyl peroxide; however, its higher rate of transient adverse effects warrants careful patient selection. Future research involving larger, randomized trials with extended follow-up periods and advanced quantitative assessment techniques is essential to validate these findings and establish long-term outcomes. These results affirm the utility of both IPL and BPO gel as effective options for managing inflammatory acne.

The study's limitations include a small sample size, COVID-19-related attrition, short follow-up duration, demographic bias toward young males, subjective improvement assessments, focus on transient effects and single-center design. Larger multicenter trials, longer follow-up periods and advanced imaging techniques are needed to strengthen findings and evaluate long-term outcomes comprehensively. Larger randomized controlled trials with more treatment sessions, extended follow-up and advanced techniques like three-dimensional skin imaging are needed to validate the efficacy and safety of both modalities, including assessing adverse effects like erythema, edema and blistering and improving the precision of acne severity assessments.

CONCLUSION

Intense Pulsed Light (IPL) therapy demonstrated slightly superior clinical improvement and faster response in managing inflammatory acne compared to benzoyl peroxide 2.5% gel, both used alongside oral azithromycin. Despite transient erythema in IPL cases, both treatments were safe and effective, offering viable options for individualized acne management strategies.

ACKNOWLEDGEMENTS

The authors wish to express their sincere gratitude to the Department of Dermatology, Venerology and Leprosy of a tertiary care center, Akola for providing the necessary support and resources for this study. We extend our appreciation to the Ethical Committee for their approval and guidance throughout the research process. Special thanks are due to the patients who participated in this study, whose cooperation and trust made this work possible. We also acknowledge the valuable contributions of the clinical staff and colleagues involved in data collection, patient management, and analysis, ensuring the successful completion of this study.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee

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