EJfîcacy of octenidine dihydrochloride and 2-phenooyethanol in the topical treatment of inflammatory acne S. Mayr-Kanhäuser, B. Kränke, and W. Aberer KEY WORDS acne, antibiotic resistance, octenidine dihydrochloride, 2-phenoxy-ethanol -A B S T R A C T Background: With the increase in antibiotic-resistant strains of microorganisms in acne lesions, the search for alternative treatment methods has become important. We studied the efficacy of a combination of the antiseptic substances octenidine dihydrochloride and 2-phenoxyethanol (O/P) in mild to moderate inflammatory acne vulgaris. Methods: Thirty patients were instructed to apply O/P once or twice daily for a 6-week treatment period. Determination of efficacy included the numerical documentation of inflammatory and non-inflammatory lesions within defined regions of the face by the investigator, and photodocumentation of the clinical picture as well as the fluorescence pattern under Wood's light. Results: Twenty-four patients completed the study. The number of papules and pustules decreased more than 50% in seventeen and nineteen patients, respectively. Acne lesions worsened in only one patient. Mild adverse reactions (erythema, burning, and scaling) were seen in two patients. Therefore, O/P was highly effective in treating inflammatory lesions of facial acne, but there was no essential efficacy in the non-inflammatory primary acne lesions. Conclusion: Topical O/P is a good and cost-effective alternative in the treatment of mild to moderate inflammatory acne lesions and may allow reduced application of anti-acne antibiotics to prevent development of resistance. Introduction Acne vulgaris is a worldwide common skin disorder of the sebaceous follicles, which are special pilosebaceous units located mostly on the face, chest, and back. Be- cause the lifetime prevalence is nearly 100%, most adolescents develop acne lesions differing only in the severity of expression. Up to 30% of the individuals involved Note: SMK was in clinical charge of the patients, and all authors designed the report presented, prepared and revised the manuscript, and approved the final version. Table 1. Patient characteristics; Patient (no., initials, sex, age) Inclusion com/pap/pust Follow-up 1 com/pap/pust Follow-up 2 com/pap/pust Follow-up 3 com/pap/pust 1. S.M. F 16 yrs 82 / 15 / 5 76 / 10 / 5 45 / 7 / 2 - 2. S.G. M 22 yrs 17 / 17 / 8 10 / 3 / 1 5 / 1 / 1 — 3. O.R. M 17 yrs 97 / 15 /12 91 / 9 / 7 80 / 3 / 2 - 4. F.S. F 18 yrs 17 / 9 / 9 12 / 8 / 4 4 / 3 / 1 - 5. S.I. F 15 yrs 60 / 25 / 17 46 / 9 / 10 28 / 5 / 4 - 6. R.J. F 22 yrs 31 / 8 / 10 19 / 17 / 7 10 / 8 / 0 - 7. E.F. M 20 yrs 115 / 12 / 3 85 / 9 / 0 115 / 5 / 0 - 8. K.A. F 17 yrs 72 / 24 / 45 36 / 8 / 5 37 / 8 / 1 - 9. L.M. F 18 yrs 28 / 29 / 14 21 / 26 / 8 19 / 27 / 7 11 / 13 / 4 10. R.M. F 23 yrs 76 / 19 / 6 55 / 12 / 4 33 / 4 / 2 - 11. R.A. F 22 yrs 48 / 17 / 11 56 / 8 / 0 40 / 6 / 0 - 12. N.W. M 18 yrs 56 / 12 / 12 37 / 9 / 0 15 / 4 / 0 - 13. P.L F 16 yrs 58 / 12 / 3 60 / 5 / 3 70 / 12 / 7 70 / 15 / 9 14. W.H. F 23 yrs 170 / 14 / 11 170 / 15 / 2 150 / 6 / 0 - 15. E.T. M 17 yrs 60 / 13 / 13 80 / 13 / 8 70 / 12 / 7 - 16. R.A. M 16 yrs 26 / 18 / 27 27 / 19 / 15 31 / 8 / 6 - 17. W.O. M 18 yrs 110 / 16 / 10 90 / 14 / 7 80 / 12 / 3 - 18. G.M. F 17 yrs 70 / 19 / 11 70 / 16 / 7 60 / 9 / 6 - 19. H.M. M 15 yrs 120 / 24 / 27 120 / 10 / 25 95 / 9 / 11 - 20. L.U. F 19 yrs 180 / 18 / 9 160 / 22 / 4 87 / 10 / 4 - 21. E.B. F 20 yrs 38 / 7 / 11 28 / 8 / 2 18 / 3 / 5 - 22. K.T. F 15 yrs 95 / 9 / 27 75 / 14 / 20 75 / 4 / 5 - 23. B.W. M 23 yrs 40 / 5 / 7 35 / 8 / 3 15 / 2 / 0 - 24. R.M F 22 yrs 76 / 19 / 6 74 / 12 / 6 53 / 17 / 6 49 / 4 / 2 Abbreviation: com = comedones, pap = papules, pust = pustules; F = female, M = male; Follow-up 1 after 2-3 weeks, Follow-up 2 after 6 weeks, Follow-up 3 after 8 weeks of therapy. require medical treatment, and systemic as well as topical antibiotics are the agents most commonly used in the therapy of inflammatory lesions such as papules or pustules (1). Unfortunately, a significant and worrying increase in the number of antibiotic resistant strains of P. acnes has been reported in the last decade (2-4). Moreover, the lowest prevalence of propionibacterial resistance can be found in young (10- to 14-year-old) patients, indicating an important role of previous treatments with antibiotics in older acne patients (5). As a result, there is a need for new non-antibiotic treatment of acne. Methods Study objective The purpose of this pilot study was to evaluate the efficacy of monotherapeutically applied Octenisept® (octenidine dihydrochloride, 2-phenoxyethanol, Schulke & Mayr, Germany), a topical skin antiseptic marketed since 1988, in patients with mild to moderate inflammatory acne. Study design The study was designed as a single-center, prospective, open-labeled clinical trial. To be included, patients had to present with more than 15 non-inflammatory lesions (white and black comedones) and more than 5 inflammatory lesions (papules, pustules and papulopustules) on their faces (6). Exclusion criteria were nodulocystic lesions, fewer than 5 inflammatory lesions, systemic antibiotic or retinoid therapy within the last 6 months, and manifestations of other cutaneous diseases of the face. Before the study started, all the patients included gave their written informed consent. At start of the study, the precise anamnestic data were evaluated including former therapies, skin type classification, atopy scoring, allergies, and medication including oral contraceptives. Figure 1a. Comedones and inflammatory acne lesions on the left cheek (inclusion phase). Figure 1b. Same patient as in 1a at the 6-week follow-up assessment. Efficacy parameters Photodocumentation and fluorescence photography, currently the best tool in the clinical assessment of acne, was performed; the investigator also counted the inflammatory and non-inflammatory lesions. Figures 1a and b (7-9). The number of lesions within defined regions of the face (forehead, and left and right cheeks including the adjacent part of the nose and chin) were documented. Because the punctate fluorescence detected with Wood's light examination corresponds to coproporphyrin III and protoporphyrin IX produced by Propionibacterium acnes, photodocumentation of this phenomenon was useful to quantify and evaluate the efficacy of acne treatment protocols (10). Figures 1a and b. Patients were instructed to clean their faces thoroughly first once a day at bedtime, and if well tolerated twice a day with O/P. In patients with atopy, the mode of application was determined as once daily in order to avoid an (hypothetical) irritant reaction. In facial regions with multiple inflammatory lesions they were instructed to apply a compress with O/P for 1 to 2 minutes twice a day. No other local or systemic acne therapy was allowed, with the exception of a skin-care product (Diprosicc®, AESCA, Austria). The efficacy and cutaneous tolerance of the therapy were assessed and documented by the investigator with the same methods 2 to 3 weeks and 5 to 6 weeks after initiation of treatment. If there was a missing response within this period, a final examination was performed after 8 weeks. Tolerability All adverse events reported during the trial were recorded. Figure 2a. Decrease of punctate fluorescence in Picture 2b. Decrease of punctate fluorescence in Wood's Wood's light before therapy. light after therapy, demonstrating treatment efficacy. Results 30 Caucasian patients with acne comedonica et papulopustulosa of the face (18 females, 12 males; age range 14 to 23 years) were included. 24 (80%) patients completed the study and 6 (20%) discontinued for the following reasons: 1 left because of visible signs of irritation due to the antiseptics, a 14-year-old girl left because she developed acne conglobata (exploration of the hormones discovered abnormalities), and 4 were lost to follow-up. In 3 (10%) patients there was no response after 6 weeks, and 2 of them showed delayed improvement after 8 weeks of treatment. In 1 patient the acne lesions worsened. In the 21 (70% of the initial study cohort) patients that improved within the treatment period, the number of pustules decreased more than 50% in 19 (63% of the initial study cohort, 83% of the patients that improved), and this increased to 21 after 8 weeks. The papules decreased in 17 and 19 patients (57% and 77%, respectively). Nine (30% and 41%, respectively) patients showed a more than 50% reduction of comedones. (Table 1) Safety Two patients developed irritant reactions such as erythema, burning, and scaling, and one of them discontinued as mentioned above. No other adverse effects were observed. Discussion For decades topical therapy with antibiotics has been the first choice in treating inflammatory acne, and in the 1970s many experts believed that P. acnes was incapable of developing resistance (11). Because antimicrobial therapy is only palliative - acne is not an infection in the traditional sense, and acne lesions usually persist for some years during the second decade of life - the majority of patients need several courses of treatment before the disease spontaneously regresses. Unfortunately, numerous studies have recently raised the issue of increased bacterial resistance in acne patients (2-4, 12, 13), and the likelihood of overgrowth of resistant P. acnes increases with the duration of antibiotic therapy (14, 15). Actually, the proportion of patients carrying strains resistant to the commonly used erythromycin, clindamycin, and tetracy-cline is reported to range from 34.5% to 64% (4). REFERENCES Octanidine is well documented to have a very good safety profile (no resorption when applied on wounds, mucous membranes, etc.) and is highly effective against a wide range of microorganisms including MRSA, Staphylococcus epidermidis, Streptococcus pyogenes, Proteus mirabilis, Klebsiella pneumoniae, E. coli, and Pseudomonas aeruginosa (16, 17). Moreover, it has a remnant effect in microbial skin decontamination, so we decided to employ O/P in the treatment of mild to moderate inflammatory acne. The results of this study show that the combination of octenidine dihydro-chloride and 2-phenoxyethanol is highly effective in treating inflammatory acne lesions (papules, pustules, and papulopustules) within 6 to 8 weeks. However, the topically-applied antiseptic evaluated does not markedly reduce non-inflammatory comedones. Because the intensity of fluorescence is known to be proportional to the amount of P. acnes (18), the applied solution seems to be effective against the Propionibacte-rial strains. Other mechanisms by which the fluorescence could be suppressed, such as destruction of the fluorescence-inducing porphyrins or decreased production of porphyrins by living P. acnes organisms, are less probable with regard to these antiseptics (19). Even if the duration of treatment phases and the time points of efficacy assessment differ in most topical treatment studies, the results of our study are solid when compared with published data. The topical retinoids currently used effectively reduce the number of comedones and inflammatory lesions in the range of 40% to 70%, while topically applied antimicrobials like clindamycin, erythromycin, tetracycline, and benzoyl peroxide attain reduction of lesions from 26% to 85% (20). Limitations of our pilot study include the absence of blinding, the limited number of participants, and concentration on facial acne. In conclusion, our open-labeled prospective pilot study showed that topically applied antiseptic therapy with a combination of octenidine diydrochloride and 2-phenoxyethanol can be an effective alternative for the treatment of mild to moderate inflammatory acne. Moreover, it is an extremely cost-effective treatment - the cost per patient for the trial period was 10.05 (about UK £7), which is less than 1% of the amount that patients are willing to accept and pay as found by Ozolins et al. (21) - and therefore seems to be an adequate alternative to established antibiotics. Furthermore, the preferential use of local antiseptics, given alone or in combination with topical antibiotics, will help decrease resistance development. 1. Brown SK, Shalita AR. Acne vulgaris. Lancet. 1998;351:1871-6. 2. Eady EA, Cove JH, Holland KT, Cunliffe WJ. 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Sedlock DM, Bailey DM. Microbicidial activity of octenidine hydrochloride, a new alkanediylbis[pyridine] germicidal agent. Antimicrob Agents Chemother. 1985;28:786-90. 17. Dettenkofer M, Jonas D, Wiechmann C, Rossner R, Frank U, Zentner J, Daschner FD. Effect of skin disinfection with octenidine dihydrochloride on insertion site colonization of intravascular catheters. Infection. 2002;30:282-5. 18. Mc Ginley KJ, Webster GF, Leyden JL. Facial follicular porphyrin fluorescence: correlation with age and density of Propionibacterium acnes. Br J Dermatol. 1980;102:437-41. 19. Burkhart, CN. Digital fluorescence as a parameter of Propionibacterium acnes suppression needs assessment. Int J Dermatol. 2001;40:101-3. 20. Haider A, Shaw JC. Treatment of acne vulgaris. JAMA. 2004;292:726-35 21. Ozolines M, Eady EA, Avery AJ, et al. Comparison of five antimicrobial regimens for treatment of mild to moderate inflammatory facial acne vulgaris in the community: randomised controlled trial. Lancet. 2004;364:2188-95. AUTHORS' ADDRESSES Sigrid Mayr-Kanhäuser, MD, Department of Dermatology und Venereology, University of Graz, Auenbruggerplatz 8, A-8036 Graz, Austria, corresponding author, E-mail: Sigrid.Mayr-Kanhaeuser@Klinikum-Graz.at Birger Kränke, MD, same address Werner Aberer, MD, professor of dermatology, same address