en Dermathology Dermathology Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:13.9pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> 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.</span><br> <span style="line-height:13.9pt"><b><i><span style="color:blue">Methods:</span></i></b> 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&rsquo;s acne score and standardized photography. Post-treatment, genotype-phenotype correlations were evaluated.</span><br> <span style="line-height:13.9pt"><b><i><span style="color:blue">Results:</span></i></b> 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.</span><br> <span style="line-height:13.9pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> 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.<i></i></span></span></span><br> &nbsp; Acne Vulgaris, Doxycycline, Azithromycin, Polymorphism 74 81 http://caspjim.com/browse.php?a_code=A-10-3829-1&slc_lang=en&sid=1 Alireza Tavakolizadeh alirezatavakolizadeh@gmail.com 100319475328460055763 100319475328460055763 No Student Research Committee, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran Hamideh Mohammadzadeh Mohammadzadeh.hamideh@yahoo.com 100319475328460055764 100319475328460055764 Yes Department of Dermatology, School of Medicine, Gonabad University of Medical Sciences,Gonabad, Iran Ali Mohammad Mokhtari mokhtariam67@yahoo.com 100319475328460055765 100319475328460055765 No Department of Epidemiology and Biostatistics, School of Health, Social Development and Health Promotion Research Center, Gonabad University of Medical Sciences, Gonabad, Iran Younes Karami youneskarami1998@gmail.com 100319475328460055766 100319475328460055766 No Student Research Committee, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran Milad Khorasani miladkh24@yahoo.com 100319475328460055767 100319475328460055767 No Department of Biochemistry and Nutrition, Neyshabur University of Medical Sciences, Neyshabur, Iran Zahra Saadatian z.saadatian@yahoo.com 100319475328460055768 100319475328460055768 No Department of Physiology, Faculty of Medicine, Infectious Diseases Research Center, Gonabad University of Medical Sciences, Gonabad, Iran Zahra Rajabzadeh rajabzadehz73@gmail.com 100319475328460055769 100319475328460055769 No Student Research Committee, Faculty of Medicine, Gonabad University of Medical Sciences, Gonabad, Iran Mohammad Amin Momeni-Moghaddam aminmomeni90@gmail.com 100319475328460055770 100319475328460055770 No Department of Nutrition and Biochemistry, Faculty of Medicine, Social Determinants of Health Research Center, Gonabad University of Medical Sciences, Gonabad, Iran