Sep 13 2023 41 mins 2
(00:00) John introduces the podcast and welcomes our guest for this episode - the founder of the Dermatology Referral Service in Glasgow, Peter Forsythe.
Chapter 1 – The Ears
(02:58) John welcomes Peter Forsythe, who talks about how he got involved in dermatology and how ear disease makes up half the caseload in the referral practice he works at.
(04:41) John asks why it is important dogs have clean ears and Peter discusses the long tube made up of the auricular and annular cartilages which are lines with glandular skin which produces wax - which combines with skin cells to make up what we know as wax. He says a build-up can alter the environment on the ear canal, increasing humidity and increasing the number of microbes such as bacteria and yeast, which - whilst normally present - can develop into an overgrowth or even infection. He also talks about the concretions, or balls of ear wax which can form adjacent to the tympanic membrane or ear drum, and they are called ceruminoliths and can sit on the ear drum and damage and even perforate it. So it is important to manage this ear wax and keep the ear clean.
(07:55) Sue asks about the ‘self cleaning’ mechanism the ear called epithelial migration and Peter describes this as similar to the shedding of cells we have on our continuously growing skin cells, but in the ear these have a sliding, upward motion to them as they do this, and this slowly carries cells and wax up and out the ear like a slow moving escalator – at the speed our nails grow at.
(09:49) Sue asks if this changes with age and Peter says there isn’t information on age changes, but in cases of inflammation or disease this is affected, slowing it down and then leading to increased build up of wax. Peter says the human ear produces 2 kilos of wax in a lifetime!
(11:32) Sue asks what Peter recommends to clients in terms of ear cleaning with puppies and he doesn’t recommend routine ear cleaning in puppies if they are healthy, as the mechanism is working well; however, he does think in those breeds where they are prone to ear disease, that it is good to get them used to you handling their ears at a young age.
Chapter 2 – The Cleaning
(13:34) Sue asks about hairy ear canals or plucking ears and Peter says in his view plucking hairy ear canals in poodles and bichons for example, where the hair can trap the wax, can irritate and inflame the ear and begin ear disease, so he wouldn’t pluck them. If the dog has got ear disease (otitis) then some plucking maybe necessary – but ear phobia – where a dog has had bad experiences and they won’t let people go near their ears, is more of an issue and plucking can lead to this. He would prefer then to begin cleaning if you can see wax building up. This is the same with a dog with a pendulous (flappy outer) ear (which can also contribute to ear disease) – but he does point out too much cleaning can overly wet the ear and cause more problems – so each case must be considered carefully.
(17:15) Sue asks as a pet owner who can see so many different ear cleaners, what can help you decide and what to look for and Peter divides these into two. Firstly softening or dissolving ear wax products called cerumenolytics, containing things like propylene glycol, mineral oils, glycerine; through to secondly salicylic acid or even stronger sodium docusate (DOSS) or carbamide peroxide (which is only recommended in anaesthetised dogs) which dissolves. Sue clarifies then this depends on how waxy the ear is as to which you reach for and Peter says it is recommended to talk to the vet about it rather than purchasing straight from the internet.
(21:10) John points out it is important then for any nurse or vet to have a good understanding of the ear cleaners on their shelves and Peter wholeheartedly agrees, saying for example a more water based ear cleaner being used to dissolve and remove wax doesn’t make sense and also cleaning isn’t comfortable for the dog; so it is important to demonstrate the use of a product to an owner, and give them tips such as warming the ear cleaner a little to make it more comfortable.
Chapter 3 – The Cleaners
(24:20) John asks about powders and Peter remembers when they were used more frequently, but he does not recommend them at all as they mix with the wax and make it stickier and dryer. John goes on to ask what changes in the ear once disease starts to set in; Peter says if a dog has had ear disease once, it is very likely to happen again and can happen repeatedly. Over time this changes detrimentally the ear canal; the lining becomes thicker and the tissues become swollen and oedematous, the glands become enlarged and even massive over time; all this narrows the ear canal and impairs the epithelial migration and so you have an increased build up or wax in a smaller canal and this favours the further build up of bacteria and/or yeast in the ear. He also says the ear drum can then weaken and even perforate, so a hole can appear and then infection can get into the middle ear which is both more serious and hard to treat. He points out if the ear disease being allowed to continue year on year this can then result in long term changes where the ear cartilage becomes calcified, so effectively into bone – at this point often only surgery can help.
(29:38) Sue mentions these dogs all have underlying issues which cause these ear problems, and flags this for a further podcast. Sue then asks about the cases where we have these changes and the presence of yeast and bacteria and asks if there should be cleaning in all of these cases; Peter replies that there is strong evidence to say that due to the increase in discharge they should all be having regular cleaning – as the normal treatment for these cases - antibiotic and or antifungal ear drops - need to be able to get to the lining of the ear through this discharge in order to work. So, they need cleaning prior to the drops going in. Sue asks if these are the antiseptic cleaners we would use and Peter agrees, saying you want the cleaner to both remove the wax build up but also have an antiseptic effect, he mentions isopropyl alcohol, para-chloro-meta-xylenol (PCMX) and in particular chlorhexidine with Tris EDTA as a common effective combination for these cases – which in some cases can resolve the disease when used as a sole treatment. Sue reflects that as in Scandinavia as heard on a previous SkinFlint, more thought is going into using these to avoid antibiotic use.
(32:47) Sue asks Peter what a practice would have as three key ear cleaners for stocking their pharmacy, Peter says three is a good number and they would want a soothing, wax softening cleaner for the low symptom waxy ears – such as a glycerine, propylene glycol or mineral oil with camomile for example. Then a more potent, cerumenolytic ear cleaner, possibly with a detergent such as DOSS or chlorhexidine or alcohol. Then the third would be an aqueous ear cleaner for use in the purulent, pus based discharge in severe cases such as a pseudomonas infection, and this would be the chlorhexidine and Tris EDTA combination as discussed.
(36:34) John wraps up and summarises the conversation.
(41:35) John asks his co-hosts the usual daft questions so we don’t take ourselves too seriously!
