Follow-Up
Because veterinarians rely on pet owners to follow their prescribed therapeutic protocols, time spent explaining proper ear care to clients helps them treat their animals’ ears as prescribed.
Clients should understand the need for frequent rechecks to monitor the progress of the pet with otitis externa. Too often patients are sent home with ear drops and then are not seen again until the otitis externa flares up. Scheduling a recheck visit allows the veterinarian to change therapy if there is no response.The external canal can be cleaned by the owner at home to facilitate removal of excessive exudate accumulation associated with otitis externa or otitis media. The author prefers an acetic acid-boric acid solution for Malassezia infection and tris- EDTA for bacterial otitis for home use, because they are antiseptic and non-ototoxic. The procedure is as follows:
• The ear canal is filled with the cleaning solution until it overflows.
• The canal is externally massaged for 5 minutes.
• The loosened debris is wiped off the external opening of the ear canal and pinna with a dry cotton ball.
• Limit the daily use of ear cleaners to 14 days. After the ear is clean, a maintenance ear cleaning once or twice weekly will prevent maceration of the ear canal epithelium.
This procedure is repeated daily at home until the recheck visit. An anti-yeast or antibacterial medication can be applied after the ear cleaning.
A 2-week recheck is required to determine the success of the therapy. If there is progress, then the regimen is continued until the cytology is negative and the patient is free of symptoms. If there are bacteria, yeasts, or white blood cells on subsequent recheck, the therapy needs to be changed accordingly.
Overtreatment of otitis externa with ear cleaners and liquid medications may indeed clear up the infection, but because the surface epithelium is macerated from all of the liquid, the ear canal remains swollen.
If the cytology is negative and the inflammation has subsided, intensive ear cleaning should be stopped completely, or a maintenance schedule should be provided to the owner. Overcleaning of the normal ear canal removes much of the cerumen, which is beneficial to the ear canal, providing a moisture barrier for the ear.A good prognostic sign that uncomplicated otitis externa is resolving is to see regrowth of hair in the vertical canal. Most of the exudates formed in the acute phase of otitis externa have a depilatory effect on the hair, so the hair falls out. When the inflammation subsides and the exudates are not dissolving hairs, hair regrowth can occur.
Frequently, after the otitis externa has resolved, the client is willing to allow the veterinarian to look for the underlying cause of the ear disease with a hypoallergenic food trial, allergy testing, or endocrine assays. Failure to identify and treat any underlying disease results in chronic otitis externa.
Suggested Readings
Foster AP, DeBoer DJ: The role of Pseudomonas in canine ear disease, Compend Cont Ed 20:909-918, 1998.
Gotthelf LN, Young SE: New treatment of Malassezia otitis externa in dogs, Vet Forum 14:46-53, 1997.
Harvey RG: Aspects of the interaction between skin and staphylococci, Bayer Selected Proceedings of the North American Veterinary Conference, January 1998.
Kiss G, Radvanyi S, Szigeti G: New combination for the therapy of canine otitis externa: microbiology of otitis externa and efficacy in vivo and in vitro, J Small Anim Pract 38:51-60, 1997.
Merchant SR, Bellah JJ: Otitis symposium, Vet Med 92:517-550, 1997.
Nuttall TJ: Use of ticarcillin in the management of canine otitis externa complicated by Pseudomonas aeruginosa, J Small Anim Pract 59:165-168, 1998.
Powell MB, Weisbroth SH, Roth L, et al: Reaginic hypersensitivity in Otodectes cyanotis infestation of cats and mode of mite feeding, Am J Vet Res 41:877-882, 1980.
Trevor PB, Martin RA: Tympanic bulla osteotomy for treatment of middle-ear disease in cats: 19 cases (1984-1991), J Am Vet Med Assoc 202:123-128, 1993.