ACCREDITED CPD - DERMATOLOGY
glycosides such as gentamycin and fluoroquinolones
such as orbifloxacin and marbofloxacin are effective.
However, the selected antibiotic should be continued
for a minimum of 6 weeks. TrizEDTA (eromethamine
and disodium EDTA dehydrate) is an aqueous preparation with efficacy against Pseudomonas spp. as is
Flamazine ( see Vet 360 May 2015 page 32 for recipes or homemade solution) \(vet360/vetlink/publications).
Glucocorticoids assist in reducing the inflammation
and subsequent susceptibility to infection as well as
secondary hyperplasia and proliferative changes (Fig
5). Prednisolone can be administered orally at 1 to 4
mg/kg once daily.
Figure 4. In many cases of otitis externa the skin of the pinna
and face can also be severley affected and need specific treatment
eration of the ear canal, and include isopropyl alcohol
and mild acids such as benzoic, acetic, boric, salicylic,
malic and lactic acids. If the ear canal is ulcerated
avoid the use of products containing alcohol or acid.
Acetic, malic, boric, benzoic, salicylic and lactic acid
also have antibacterial action, however a lower pH inactivates aminoglycosides and fluoroquinolones.
Fungal otitis
Malassezia spp are a normal commensal inhabitant of
the ear. Increases in numbers is a secondary change
treatment off the underlying cause will normally reduce numbers to normal. In true infections Malassezia pachydermatitis is the species routinely involved
and this usually responds to azole antifungals. Azoles
include clotrimazole and miconazole. However, recently developed triazole antifungals such as variconazole (Vfend®) and posaconazole may be more
effective. Candida, although a common cause of fungal disease in humans, is rarely encountered in companion animal otitis. In these cases, polyene macrolides, such as nystatin is advised
Approach to managing chronic otitis
Owners should be informed of correct ear cleaning
procedures. Frequency of cleaning usually decreases over time to once or twice weekly as a preventive
maintenance procedure. Owners should be warned
to keep the pet as dry as possible, and avoid swimming. Dogs with confirmation defects such as hirsute
or pendulous ears may need to have regular clipping
of the pinnae.
The ear canals should be kept dry and well ventilated.
Topical astringents prevent water from entering the
ear canals in dogs that swim frequently, minimizing
maceration of the ear canal. Chronic maceration
impairs the barrier function of the skin, which predisposes to opportunistic infection. Preventative otic astringents may decrease the frequency of bacterial or
fungal infections in moist ear canals.
Clipping hair from the inside of the pinna and around
the external auditory meatus, and plucking it from hirsute ear canals, improves ventil ][ۈ[