Angiotensin-converting enzyme gene insertion/deletion polymorphism and its impact on response to azithromycin and doxycycline treatment in acne vulgaris patients.

Background: Acne vulgaris (AV) is a common inflammatory skin disorder. Systemic treatments like azithromycin and doxycycline are frequently used. The Angiotensin-Converting Enzyme (ACE) has been implicated in inflammation and skin diseases. This study investigated the association between ACE I/D polymorphism and therapeutic response to azithromycin versus doxycycline in moderate AV. Methods: This clinical trial enrolled 54 moderate AV patients divided equally into two groups: one received 100 mg/day doxycycline, the other 250 mg/day azithromycin for 3 months. DNA was extracted via salting-out method, and ACE I/D polymorphism was analyzed by PCR and electrophoresis. Treatment efficacy was assessed using Michelson's acne score and standardized photography. Post-treatment, genotype-phenotype correlations were evaluated. Results: The doxycycline group showed significantly higher recovery rates (59.3%) compared to azithromycin (18.5%) (p<0.001). However, no statistically significant association was observed between improvement percentages and genotypes in either the doxycycline ((P = 0.567) or azithromycin (P = 0.533) groups. Conclusion: Doxycycline was significantly more effective than azithromycin for moderate AV. However, no significant association was found between ACE I/D polymorphism and treatment response for either antibiotic. These findings guide therapeutic selection while suggesting that ACE genotyping may not predict treatment response in moderate AV.