A topical steroid without an antibiotic cures external otitis efficiently: a study in an animal model

Abstract

In an animal external otitis model, inflammatory reactions were evoked by mechanical stimulation of the rat ear canal skin. The rats were in four groups: group A treated with a group III steroid, betamethasone dipropionate; group B treated with hydrocortisone combined with oxytetracycline; group C treated with hydrocortisone with oxytetracycline and polymyxin B added; Group D, the controls, treated with saline. All rats were observed otomicroscopically daily during the first 7 days after treatment and then on days 10 and 20. A standardized scoring system was used to evaluate colour, swelling and effusion of the ear canal. Histological specimens were collected on days 3, 7, 10 and 20. The most rapid improvement in the ear canal status occurred in the animals treated with betamethasone dipropionate. The inflammatory reaction of the ear canal skin caused by mechanical stimulation was characterized by oedema of the stroma but few inflammatory cells were present. The surface of the epithelium towards the connective tissue layer was smooth in the group III-treated animals (group A) whereas other groups had irregularities of the basal membrane. From this study it is inferred that the group III steroid betamethasone dipropionate alone heals experimentally induced external otitis more rapidly than hydrocortisone with oxytetracycline, with or without polymyxin B. These findings should be considered in future clinical trials of external otitis.

External otitis caused by infection with Pseudomonas aeruginosa or Candida albicans cured by use of a topical group III steroid, without any antibiotics

“…Furthermore, a solution of a potent steroid alone (BD) cured experimental EO more effectively than a weak steroid combined with an antibiotic (HCPB). These findings resemble those of an earlier study [9], in which topical treatment with the same group III steroid, BD, cured uninfected EO more effectively than HCPB. Obviously, inflammation is a major mechanism in the development of EO, irrespective of the presence of either bacteria or fungi.…”

“…In that instance, inflammation of the ear canal skin was caused experimentally by mechanical stimulation. It was also shown [9] that the effects of drugs could be investigated in this model. However, those earlier studies of the EO model did not include any microbial involvement.…”

Current bacteriology of chronic otitis media with effusion: High rate of nosocomial infection and decreased antibiotic sensitivity

“…This topical preparation apparently does not cause significant bacterial resistance. 16,17 In this study, patients who showed persistence of PTTO after 7 days of treatment or who developed systemic symptoms, such as fever or otalgia, were treated with systemic antibiotics, with the choice of antibiotic being based on the results of bacterial culture and antibiotic sensitivity testing. All 67 patients with PTTO were successfully treated.…”

Tube associated otorrhea in children with recurrent acute otitis media; results of a prospective randomized study on bacteriology and topical treatment with or without systemic antibiotics

“…This type of topical preparation also seems to have the advantage of not causing any significant bacterial resistance [8]. The action of the hydrocortisone component alone is not sufficiently studied to comment on, but there are evidence collected for other steroids and their effectiveness in treatment of infections of the EAC (external otitis) [9,10]. It also seems to be more effective to use a combination of topical antibiotics and a steroid in treatment of tube otorrhea than to use topical antibiotics alone [11].…”