Acidifying therapy, best choice in otitis external Introduction Medicus) and Farnli (the family medicine appendix of the Index Medicu s). Lit­ Since 1976, a group of about 15 experi­ erature references found in the selected enced general practition ers, staff members publications were traced and two ENT E.ROOYACKERS-LEMMENS of the department of general practice in textbooks were consulted. Articles were E. VAN DE L1SDONK Nijmegen , meet once a month to discuss excluded from further study when they P. GIESEN common problems in general practice. In concerned one of the following subjects: 1992 some conferences were addressed to malignant otitis externa; in vitro research; Rooyackers-Lemmens E, Van de Lisdonk otitis externa and an orientation in lit­ surgical therapy; CT-scan. Case-reports EH, Giesen P. Acidifying therapy, best erature was made. Otitis externa is defined and reports concerning undefined otitis choice in otitis externa? Huisarts Wet 1993; as an inflammatory condition of the skin were also excluded. This procedure 36(Suppl): 31-5. of the external ear canal. In the Nether­ yielded 51 articles. First of all, these ar­ lands, incidence-figures from general ticles were scanned for information on Abstract Literature was reviewed in order to practice amount to 12-14 cases per 1000 aetiology. Secondly, reports from clinical define a rational therapy in otitis extema based upon aetiology and predisposing factors. In patients per year. It almost equally affects trials were studied, comparing different most casesa bacterial infection turnedout to be all age groups and both sexes.!" Otitis drugs (and/or placebo) in the treatment of present (mainly Pseudomonas Aeruginosa or externa occurs most frequently in summer otitis externa. Reports of trials in which Staphylococcus Aureus); also, an allergic con­ and in humid tropical areas. Patients com­ different brands of eardrops were com­ tact dermatitis or mycosis can be present, par­ plain of pain, itching, discharge and, less pared, while each contained a combination ticularly in chronic otitis extema. The medica­ often, hearing loss or a plugged feeling. of an antibiotic and a corticosteroid, were tion of choice is Aluminium acetotartrate. Re­ Otoscopy reveals erythema, edema and excluded. sistentcasescanbetreatedwithtopicalantibio­ discharge or desquamation" Acute and tics or topical steroids. Combination of both chronic forms can be distinguished. Seven studies were found and critically drugs is not recommended.Research ingeneral Simple acidifying therapy is recom­ reviewed according to the following crite­ practice is neededtostate theoutcomesof using these guidelines. mended for the acute form; there are no ria:" concrete recommendations for chronic - was the study based on an 'inception­ otitis externa. Moreover, it is only in Dutch cohort ' ? literature that a distiction between a dry was the referral pattern described ? E. Rooyackers-Lemmens, vocational trainee; E.H. van de Lisdonk, GP, MD; P. Giesen, GP. and a wet form of otitis externa is made."!' were the exclusion-criteria described? Correspondence: E.H. van de Lisdonk, It is not clear whether this clinical distinc­ has complete follow-up been Department of generalpracticeandsocial tion corresponds with different aetiologi­ achieved ? medicine, Catholic University of Nijmegen. cal factors and, consequently, should be were the demographic and clinical Verlengde Groenestraat 75. 6525 EJ Nijmegen. treated differently. In the Netherlands, characteristics of patients and controls daily practice does not seem to correspond described ? with the advice for acidifying therapy, at was the study designed as a randomized least not according to daily practice of the controlled trial? members of the conferences. In order to have patients and controls been reach consensus on the management more matched for clinical characteristics? knowledge about the aetiology was re­ have objective outcome criteria been quired . Therefore a study of literature was developed and used? conducted, in order to find the answers to was the outcome assessment 'blind'? the following questions: • Which factors play a part in the aetio­ Aetiology logy of otitis externa? • Is a treatment with acidifying eardrops The ear canal is well protected against justified in view of these factors? infections by the acidity (pH 5-5,7) of the meatal skin, by the water-resistant, bacte­ Methods riostatic and bactericidal qualities of ce­ rumen (thanks to the polyunsaturated fatty Using otitis externa as a keyword, the lit­ acids in cerumen), and by the outward erature of the last 10 years was screened migration of the meatal skin with about 1,5 referring to Medline (the automatized bib­ mm per monrh.P'" This natural protection liographic data collection of the Index can decrease as a result of: HUISARTS EN WETENSCHAP 1993; 36(Suppl) 31 - tissue maceration in case of high envi­ ronmental temperature and humidity Table 1 Cultures ofpatients with otitis externa and controls. Percentages (tropical climate, swimming); - damage of the skin, caused by for Health y ear canal Otitis externa 38 6 example scratching or syringing the Dibb Man ni Calderon 19 Dibb Manni Calder on ear, or a corp us alienum (hearing aids !); n=77 n=21 n=29 n=226 n=54 n=29 - dermatological diseases, such as ecze­ Diphteroids 32 38 86 48 ma, psoriasis; 86 81 - alkaline pH, caused by using soap; Staphyloc. C-* 83 90 52 - absence of cerumen, caused by vigo r- S. aureus 4 8 34,1 18 11 ous cleaning of the ear canal, chronic Pseudomonas aeruginosa 22,1 38 50 inflammation, or long-term topica l ap­ B-hemolyt. streptococ 15,5 4 plication of steroids; Proteus sp 3,5 9 - host resistance lowering conditions Klebsiella sp 5,3 11 3,7 like diabetes, anemia; E.coli 3,5 1,9 anatomical variants, such as a narrow Candida alb 9,3 14 ear canal. Aspergillus sp. 24 The connection between swimming and No growth 9 10 5 4,4 8 1,9 otiti s externa has been confirmed in con­ * C- = coagulase-negative, predom inantly S. epidermidis trolled studies.":" No controlled studies regarding any of the other ment ioned pre­ disposing facto rs were found.' 89141520-34 Table 2 Seven studies concern ing compara tive trials to the medication Infection is an important cause of otitis treatm ent ofotitis externa externa; table 1 shows the results of cul­ tures made ofdiseased and normal ears . In References 16 55 50 52 56 57 24 gene ral, the micro-organisms predomi­ Number of patients 126 24 66 46 179 110 83 (a) (b) (c) (d) (e) (f) nantly isolated in otitis externa are Pseu­ Therapeutics (f) domonas aeruginosa (17-64 per cent) and 1 Start cohort + + + + + + + Staphylococcus aureus (11-46 per cent). 2 Selection of patients + + + Pathogenic bacteria are sporadically 3 Exclusion criteria + + + + + found in the healthy external ear canal of 4 Percentage patients control persons." 19 21 35-3? In Norway, dur- follow ed + + * + + * + ing a whole year, a high incidence of S. 5 Characteristics aureus was found together with a low in­ - demog raphic + + cidence of fungi and yeasts,' whereas in - cinical + + + + swimmers and in subtropical areas a high 6 Randomized + + + + + + + :j: incidence of Pseudomonas was found 7 Matching + 8 Criteria end-results + + + + + + toget her with a moderate high incidence of 9 Double-blind + + + + + fungi and yeasts." 19 Fungi and yeasts also play a role in the following situations: * drop-outs >20 per cent. :t: match ing w as negative (groups were not corresponding). chronic otitis externa; long-term treatment with eardrops containing a corticosteroid; (a) aluminium acetate w ith a comb ination preparation (combination of an antibiotic and steroid) prolonged prophylactic treatment with (b) a solution of boric acid 4% and alcohol 25% w ith two combi nation preparations (c) aluminium acetate w ith a top ical antibiotic antibiotics; in immunocompromised pa­ (d) hydrocortisone-butyrate w ith a combination preparation tients," ?3? 3940 Ie) acetic acid 2% in aluminium acetate w ith VoSol(R) (chemical composit ion: 2% acetic acid in a propvlene-qlvcol vehicle of 3% propvlene-q lvcol-diacetate, 0.02% benzethonium-chloride en 0.015% In otitis externa of more than two sodium-ac etate) and VoSol-hydrocortisone (VoSol - HC) w ith a combination preparation months' durat ion, 18 per cent of the cul­ (f) VoSol - HC w ith a combination preparation tures showed no micro-organisms or a nor­ mal flora (Staphylococci other than S.aureus, corynebacteria)." In such cases an allergic contact dermatitis should be considered; for example caused by chemi­ cal substances in hearing aids, hair-dye, 32 HUISARTS EN WETENSCHAP 1993; 36(Suppl) a superinfectioncausedby resistantorgan­ Management of otitis externa in daily general practice isms and could cause hypersensitivity to one of the antibiotics.8911 44 In the USA, • Cleaning of the ear canal. Advise pa­ 2 No improvement and itching or a dry, eardrops containing both an acidifying tients not to do this themselves. scaly ear canal: start corticosteroid solution and a corticosteroid are recom­ • Inspection, with special attention to containing eardrops. mendedincaseof otitisexternain patients the ear drum (otitis media, cholestea­ toma, perforation). A small number of patients will keep with eczemaor psoriasis." • Medication treatment: aluminium symptoms. In case of chronic otitis ex­ Medicaltreatmentof otitis externa was acetotartrate 6 dd 2 eardrops during 1 terna the following points ought to be the first subject of 17 of the 51 selected week (anti-microbial, dries the exter­ considered: articles. Of these 17 articles, 6 were re­ nal canal, not ototoxic); in case of • Avoid a warm humid environment views for postgraduate education, 2 were edema or discharge, first place a cot­ (swimming), leave off hearing aids follow-up studies of one treatment, 2 were ton plug in the canal and keep it wet (temporarily). studies of the effectsof cleaningthe exter­ with the aluminium acetotartrate • Culture for fungi and yeasts, espe­ nal auditorycanal," 48 and 7 were clinical drops for 24 hours.