Vet Dermatol 2021
DOI: 10.1111/vde.12995
Malassezia otitis unresponsive to primary care:
outcome in 59 dogs
Johann M. Boone
, Ross Bond
, Anette Loeffler
, Ewan A. Ferguson and Anke Hendricks
Department of Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK
Correspondence: Johann M. Boone, Dermatology for Animals, 263 Appleby Road, Stafford Heights, 4053 QLD, Australia.
E-mail: jboone7@alumni.rvc.ac.uk
Background – Otitis externa (OE) is a common disorder in dogs. Infection by the commensal yeast, Malassezia
pachydermatis, may result in chronic disease that does not respond to standard primary care. Chronic infectious
OE may be associated with otitis media (OM).
Hypothesis/Objective – To report medical management, clinical outcomes and frequency of middle ear involvement, in dogs with Malassezia otitis unresponsive to primary care.
Animals – Fifty-nine dogs from one referral veterinary hospital from January 2007 to September 2018.
Methods and materials – Retrospective analysis of medical records of dogs referred with chronic otitis and
treated for Malassezia otitis at a referral veterinary hospital.
Results – Chronic Malassezia OE was treated successfully in 91% of ears, in 87% of these cases with one ear
flush intervention. Median time-to-resolution was 27 days after ear flush intervention. Neither duration of otitis,
presence of neutrophils in aural discharge nor administration of oral itraconazole affected clinical outcome. Malassezia OM occurred concurrently in 17% of ears.
Conclusions and clinical relevance – These findings assist clinicians and carers of affected dogs in decisionmaking, by documenting that most cases of canine Malassezia otitis that have not resolved with standard primary care, can be treated successfully with a well-staged and intense medical treatment plan. Malassezia OM
should be suspected to occur concurrently in around a fifth of affected ears.
Introduction
Otitis externa (OE) is a common diagnosis in dogs and
accounts for ≤10% of all canine disorders recorded by
primary-care veterinary practitioners in the UK.1 It is a disorder with significant impact on health-related welfare in
dogs.2 Otitis externa develops as a result of predisposing,
primary, secondary and perpetuating factors.3 Although
allergic skin disease is a common primary cause of OE in
dogs, secondary infection (bacterial or fungal) is usually
the reason dogs are presented for veterinary attention.4
Accepted 1 April 2021
Sources of Funding: This study was self-funded.
Conflicts of Interest: Johann Boone has none to declare. Ross
Bond has received funding from or otherwise collaborated with
Dechra Veterinary Products, Bayer Animal Health, Ceva Animal
Health, MSD Animal Health and Elanco. Anette Loeffler has no
conflicts applicable to this study; she has received honoraria, consulting fees and/or has collaborated with Dechra Veterinary Products, Bayer Animal Health, Novartis Animal Health and Hill’s Pet
Nutrition. Ewan Ferguson has none applicable to this study. Anke
Hendricks has none applicable to this study; she has previously
received speaker or consultancy fees and benefited from institutional support from Dechra Veterinary Products, Purina, Novartis
Animal Health, Zoetis and Elanco.
This Abstract was published in the British Small Animal Veterinary Association Congress 2020 Scientific Proceedings.
© 2021 ESVD and ACVD, Veterinary Dermatology
Malassezia pachydermatis has long been recognised
as a commensal yeast in the ear of dogs and may be
associated with OE.5,6 In primary-care practice, most
cases of Malassezia OE (MalOE) are thought to respond
to therapy with combination products authorised for the
topical treatment of infectious OE.7,8 However, the
authors regularly encounter cases of chronic (persistent
or recurrent) otitis in their canine referral caseload, with
Malassezia as the only identifiable pathogen, based on
cytological results from aural discharge alone or in combination with negative aerobic or anaerobic bacterial culture. As the sole pathogen, Malassezia has been
identified in 8% and 26% of OE cases.9,10
In such cases, there is a need not only to address the
infectious cause, but also to identify and manage predisposing, primary and perpetuating factors such as stenosis
of the ear canal, accumulation of debris and middle ear
disease.11 Otitis media (OM) is most commonly thought
to occur in dogs when infection extends into the middle
ear from the ear canal via a defect in the tympanic membrane,12 and has been reported to occur in as many as
80% of cases with chronic bacterial OE.13 Whilst Malassezia is not as well-recognised a cause of OM, several
studies have isolated yeast microbes from the middle ear
of dogs with OM.13–15 Malassezia was reported to be the
sole pathogen in five of 22 dogs with OM.13
The aim of this retrospective case series was to
broaden recognition of the role of Malassezia in chronic
otitis in dogs, to assist primary care clinicians and carers
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Boone et al.
of affected dogs with management decisions by summarising treatment and clinical outcomes in MalOE cases
treated at a referral veterinary hospital, and to report the
frequency of concurrent Malassezia OM.
Methods and materials
Study population
Dogs with chronic ear disease were identified by searching the practice management system of a large veterinary referral and teaching
hospital (Queen Mother Hospital for Animals, UK) for dogs referred
to the dermatology service, having had an otoscopic examination and
ear flush procedure under general anaesthesia, and a computed
tomography (CT) scan, between 1 January 2007 and 10 September
2018. A parallel search of the hospital’s patient record system for the
terms “otitis” and “Malassezia” over the same period was conducted using the Veterinary Animal Surveillance System interface.16
For all dogs identified in both searches, records then were searched
individually to select patients meeting the following inclusion criteria:
(i) duration of ear disease episode of at least two months; (ii) having
undergone at least one (video)otoscopy-guided ear examination, irrigation and sampling procedure under anaesthesia (designated ear
flush intervention, EFI; the day of the first recorded ear flush was
then designated EFI1); (iii) having had a CT scan of the ears within
four weeks of EFI1; (iv) having had at least one re-examination within
six weeks of EFI1; and (v) having a recorded diagnosis of otitis with
Malassezia infection or overgrowth (henceforth referred to as Malassezia otitis) in at least one ear canal at EFI1. A diagnosis of Malassezia otitis was accepted if there was additionally a record of: (vi)
cytological evidence of Malassezia yeasts in aural discharge at EFI1
judged clinically relevant by the attending clinician; and (vii) absence
of bacteria on cytological evaluation or culture of aural discharge at
EFI1 and the visit immediately preceding EFI1.
For comparison of signalment data, a denominator population of
chronic otitis cases was generated by identifying dogs seen at the
referral hospital during the same period, with ”otitis” (VetCompass),
having undergone a (video)otoscopy and CT scan and that did not
otherwise match the study criteria.
Data extraction and definitions
Data extracted from EFI1 and the visit preceding EFI1 case records
included: signalment, age at onset of ear disease, duration of presenting episode of ear disease, CT findings and status of ear disease.
Data extracted from subsequent visits included: number of EFI, status of ear disease, oral medicines prescribed, topical products prescribed, date of first documented absence of infection or overgrowth
and date of the last visit (relevant to that episode of ear disease).
Otitis status at EFI1 was recorded as either MalOE or “MalOE
with concurrent Malassezia OM” (MalOE/OM). Diagnosis of MalOE
was assigned based upon recorded diagnosis of OE and an absence
of middle ear pathological findings on CT imaging. A diagnosis of
MalOE/OM required cytological detection of yeast microbes within
debris aspirated directly from the middle ear, in the presence or
absence of soft tissue attenuating material in the middle ear on CT
imaging.17 If MalOE was associated with bacterial or sterile OM in
the same ear, this ear was excluded from the study.
Medications administered before or after EFI1 were categorised
as oral medicines (anti-inflammatory, antifungal or antibacterial) or
topical products (medicinal ear drops and other ear solutions). Medicinal drops were further categorised as combination products (containing an antifungal, glucocorticoid and antibacterial agent), antifungalonly or glucocorticoid-only products.
Resolution of MalOE was based on recorded clinician judgement
in combination with either cytological absence or paucity of
microbes.18 Time-to-resolution was calculated from the date of EFI1
until the date of the visit first documenting resolution. Ears in which
resolution was not documented before or at the last recorded visit,
were considered treatment failures. The study end was the date of
2
the visit at which resolution was first documented or the date of the
last relevant visit with the dermatology service.
Statistical analysis
Pure-bred dogs were grouped by breed clades showing >50% bootstrap support, based on the breed cladogram of Parker et al. 2017.19
Data were analysed in SPSS v26 (SPSS Inc.; Chicago, IL, USA). The
normality of data distribution was tested using the Shapiro–Wilk test.
Spearman’s rank correlation coefficient was used to evaluate correlation between duration of ear disease and median time-to-resolution
in MalOE cases. Odds ratios (OR) were calculated for risk factors for
diagnosis of MalOE/OM and clinical outcomes in MalOE cases. Confidence levels were set at 95% and the chosen level of significance
was P < 0.05.
Results
Fifty-nine dogs met the inclusion criteria and contributed
82 ears with Malassezia otitis to the study. Figure 1 summarises the case inclusion process at the dog and ear
levels, and reasons for exclusion.
Signalment and ear disease history
Table 1 summarises signalment, age at onset of ear disease and duration of the presenting otitis episode of the
study population. Breed clade data are further detailed in
Supporting information, Table S1. In the denominator
population (n = 306), the retriever (33 of 306, 11%) and
spaniel (72 of 306, 24%) clades were highly represented;
however, retrievers had over three-fold greater odds of
matching the study criteria [OR 3.4, confidence interval
(CI) 1.7,6.5; P = 0.0002). The sex and neuter status profile (Table 1) was similar to the denominator population.
Otitis status
Of the 59 study dogs with a recorded diagnosis of Malassezia otitis in at least one ear, 34 (58%; CI 45%,69%) had
bilateral disease irrespective of the type of infection in the
contralateral ear, and 25 (42%; CI 31%,55%) had unilateral ear disease. Of the 34 dogs with bilateral ear disease,
23 of 34 had Malassezia otitis diagnosed in both ears
(n = 46 ears) and 11 of 34 dogs had Malassezia otitis
diagnosed in only one ear (n = 11 ears), with bacterial or
mixed (bacterial plus Malassezia) infection in the contralateral ear. Overall, 23 dogs contributed both ears to
the study and 36 dogs contributed one ear to the study
(Figure 1).
Fifty of 59 dogs with Malassezia otitis had a diagnosis
of MalOE only, eight of 59 dogs had MalOE/OM, and one
of 59 dogs had MalOE in one ear and MalOE/OM in the
contralateral ear. In ears diagnosed with MalOE at EFI1,
the tympanic membrane was recorded as partially visible
or not visible in eight of 68 ears, opaque/thickened in 19
of 68 ears, and having a bulging pars flaccida in four of 68
ears and a small tear in one of 68 ears.
Nine of 59 dogs had at least one ear with MalOE/OM
and contributed 14 of 82 (17%; CI 10%,27%) ears with
MalOE/OM to the study. Of the nine dogs with middle
ear disease, five had bilateral MalOE/OM, three had bacterial, mixed-microbial or sterile OM in the contralateral
ear and one dog had MalOE in the contralateral ear
(Table S2).
© 2021 ESVD and ACVD, Veterinary Dermatology
Clinical outcomes Malassezia otitis
VetCompass search
‘‘otitis’’ and ‘‘Malassezia’’
n = 1132 dogs
Hospital records electronic search
‘‘otoscopy’’, ‘‘ear flush’’, ‘‘CT scan’’
n = 234 dogs
n = 173 dogs
Excluded
No combined anaesthetic/ear flush
n = 13 dogs
Excluded
No CT scan ≤ 4 weeks
n = 2 dogs
Excluded
n = 35 dogs
n = 138 dogs, 276 ears
Excluded
No revisit ≤ 6 weeks
n = 20 dogs
Excluded
Immediately referred to surgery
n = 4 ears
Included (both ears)
n = 23 dogs, 46 ears
Included
n = 59 dogs, 82 ears
Excluded
Bacteria present
n = 115 ears
Excluded
n = 194 ears
Included (one ear)
n = 36 dogs, 36 ears
Excluded
Malassezia absent
n = 75 ears
Figure 1. Case inclusion process for the study population (n = 59 dogs, n = 82 ears).
Table 1. Signalment, age of onset of ear disease and disease duration in the study population (n = 59 dogs, n = 82 ears)
No. dogs (or ears)
Breed
Retriever clade
Spaniel clade
Other pure-bred
Cross-bred
Sex
Male
Entire
Neutered
Female
Entire
Neutered
Age
Age at reference visit
Otitis
Age at first onset:
Data not reported
<1 yo
1–3 yo
>3 yo
Duration of otitis:
Data not reported
Data reported
<7 m
≥7 m
%
CI%
Median
Range
17
15
20
7
29
25
34
12
19,41
16,38
23,47
6,23
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
10
30
17
51
9,29
38,63
n/a
n/a
n/a
n/a
2
17
3
29
0,12
19,41
n/a
n/a
n/a
n/a
59
n/a
n/a
4 y 10 m
11 m–12 y 2 m
8
12
22
17
n/a
24
43
33
n/a
14,37
30,57
22,47
n/a
n/a
n/a
n/a
n/a
n/a
n/a
n/a
(19)
(63)
(31)
(32)
n/a
n/a
49
51
n/a
n/a
37,61
39,63
n/a
7m
n/a
n/a
n/a
2 m–2 y
n/a
n/a
m months, n/a not applicable, y years, yo years old.
During either the visit preceding EFI1 or EFI1, neutrophils were identified in aural discharge in 24 of 68
(35%) ears with MalOE and four of nine ears with MalOE/
OM.
Duration of ear disease of seven months or more (OR
1.68, CI 0.43,6.65; P = 0.23) and identification of
© 2021 ESVD and ACVD, Veterinary Dermatology
neutrophils in aural discharge (OR 0.73, CI 0.21,2.59;
P = 0.31) did not affect the odds of being diagnosed with
MalOE/OM.
Foreign bodies or mass lesions were not identified in
any of the ears included in the study. Of those 51 dogs
diagnosed with MalOE, 22 (43%; CI 30%,57%) dogs had
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Boone et al.
indicating lack of resolution. The duration was 28–91 days
between the first and second EFI (four dogs), and
36 days between the second and third EFI (one dog).
After EFI1, most dogs with MalOE still received an oral
glucocorticoid and less than a third received oral itraconazole; however, almost all MalOE ears (64 of 68, 94%)
received topical antifungal treatment. Combination ear
drops were prescribed most commonly.
Two dogs (three MalOE ears) received no topical antifungal therapy at any time yet did receive oral itraconazole: one had a suspected contact dermatitis to topical
products and one would not tolerate topical therapy. Resolution of infection in those ears occurred at days 13, 27
and 27 of treatment post-EFI1. One dog (one MalOE ear)
received no antifungal treatment and instead received
oral prednisolone and an ear cleaning product after
removal of a ceruminolith at EFI1.
Topical ear solutions other than medicinal ear drops
(generally referred to as “ear cleaning products”) were
used in just over half (35 of 68, 51%) of the ears with
MalOE at some point during treatment; owing to the
diversity of products and treatment protocols, these are
not reported further.
pruritus or erythema at sites distant to the pinnae
recorded at presentation or during the study.
Medication and ear flush interventions
Median duration of time from first presentation at the
hospital to EFI1 was 17 days (range 0–77 days). Table 2a
summarises oral medicines and Table 2b medicinal ear
drops prescribed to study dogs.
Before EFI1, 46 of 59 (78%) dogs received oral
(methyl)prednisolone: either an average dose of 0.8 mg/
kg prednisolone once daily (range 0.32 to 1.17 mg/kg/day)
or a comparable dose of methylprednisolone. Four of 59
(7%) dogs received oral itraconazole and 23 of 82 (28%)
ears received topical antifungal treatment.
Owing to the low number of dogs with MalOE/OM,
interventions for this group are not specifically reported
here.
Forty-six dogs (60 of 68 ears, 88%) with MalOE underwent one EFI, four dogs (six of 68 ears, 9%) underwent
two EFIs and one dog (two of 68 ears, 3%) underwent
three EFIs by the study end. Repeat EFIs were performed
in cases where there was cytological evidence of persistent infection or accumulation of debris following EFI1,
Table 2. Summary of (a) oral medicines and (b) medicinal ear drops prescribed to Malassezia otitis cases before and after ear flush intervention 1
(EFI1)
(a) Oral medicines
Anti-inflammatory
Prednisolone
Methylprednisolone
Ciclosporin
Meloxicam
None
Antifungal
Itraconazole:
With topical antifungal
Without topical antifungal
None
Antibacterial
Amoxicillin-clavulanic acid
Cefalexin
None
Presentation to EFI1
EFI1 to study end
All dogs (n = 59)
Dogs with MalOE (n = 51)
No. dogs
%
CI%
No. dogs
%
CI%
43
3
2
0
11
73
5
3
0
19
60,83
1,14
0,12
0
11,31
40
5
3
1
2
78
10
6
2
4
65,88
3,21
1,17
0,11
0,14
1
3
55
2
5
93
0,10
1,14
83,98
12
2
37
23
4
73
14,37
0,14
59,83
1
0
58
2
0
98
0,9
0
90,100
0
1
50
0
2
98
0
0,11
89,100
All ears (n = 82)
(b) Medicinal ear drops
No. of different products
One
Two
Three
None
Type of ear drops prescribed
Combination
Antifungal-only
Glucocorticoid- only
Total
Ears with MalOE (n = 68)
No. ears
%
CI%
No. ears
%
CI%
31
0
0
51
38
0
0
62
28,49
n/a
n/a
51,72
54
8
2
4
79
12
3
6
68,87
6,22
0,11
2,15
No. of products
%
CI%
No. products
%
CI%
12
11
8
31
39
35
26
100
24,56
21,53
13,43
56
20
11
87
64
23
13
100
54,74
15,33
7,21
MalOE otitis externa with Malassezia in aural discharge, CI confidence interval, 95%.
4
© 2021 ESVD and ACVD, Veterinary Dermatology
Clinical outcomes Malassezia otitis
Treatment outcomes for Malassezia otitis externa
cases
As a consequence of low numbers of MalOE/OM ears in
this study, clinical outcomes and risk factors are reported
for MalOE ears only. Table S2 lists the number of EFI and
treatment outcomes for ears diagnosed with MalOE/OM.
Sixty-two of 68 (91%) ears diagnosed with MalOE had
a successful outcome with resolution of infection. At the
time of resolution, 57 of 62 (92%) MalOE ears had no
cytological evidence of yeast microbes and five of 62
(8%) had yeast numbers reported as “rare” (two of five),
“rare/consistent with normal” (two of five) and “few/consistent with normal” (one of five) by the clinician. Neutrophils were recorded in five of 62 of ears at the time of
clinical resolution, in the absence of yeast microbes.
Median time-to-resolution was 27 days (range 7–
178 days) in MalOE cases. Of 62 of 68 MalOE ears with a
successful outcome, 54 of 62 (87%) resolved after only
one EFI. Seven of 62 MalOE ears were recorded to have
infection resolved within two weeks of EFI1. In only two
of these ears was the total treatment time, from the visit
preceding EFI1 to resolution, less than four weeks (13 and
17 days, respectively). Of the six of 68 (9%) MalOE ears
with an unsuccessful outcome, two ears were referred for
surgical intervention and four ears were lost to follow-up.
There was no significant correlation between duration
of ear disease and median time-to-resolution (rs = 0.19).
The presence of neutrophils in aural discharge (OR 0.51,
CI 0.10,2.76; P = 0.22) and prescription of itraconazole
(OR 0.88, CI 0.15,5.25; P = 0.45) did not affect the odds
of having a successful outcome in ears with MalOE.
Discussion
In 1964, Spruell wrote that “The incidence of otitis
externa is so high, and the distribution so widespread,
that the spate of attention the problem has received during the last 10 years is fully justified”.12 Almost 60 years
later, despite the development of multiple new ear products, this statement is still valid. Intervention trials with
topical therapeutics for unspecified OE have reported
success rates between 65% and 81%.9,10,20–22 The
potential for chronic disease is highlighted by a report that
24% of dogs presenting for otitis had one or multiple
recurrences following initial treatment with topical combination products.23 Reasons for incomplete or lack of resolution, or recurrence of otitis after a course of treatment,
are likely to variably reflect treatment-related (effectiveness, frequency, duration and compliance) and ear
disease-related (predisposing, primary, secondary and
perpetuating) factors3 that can be difficult to address, particularly within the confines of a busy primary care practice environment.
Although Malassezia frequently is found in combination
with bacteria in canine OE,21,24,25 the present study was
deliberately limited to treatment of otitis cases unresponsive to primary care and associated with Malassezia infection/overgrowth in the cytological absence of bacteria, to
provide a preliminary clinical practice benchmark for this
more defined clinical subset.
This case series demonstrates that most (91%) cases
of chronic Malassezia OE in dogs, unresponsive to
© 2021 ESVD and ACVD, Veterinary Dermatology
primary care treatment, can be treated successfully with
a medical treatment plan, typically within four weeks (median 27 days) of one (87%) ear flush intervention. In the
few cases where resolution of infection occurred faster,
it is possible that significant response occurred before
the scheduled ear flush or the previous treatment history
was inaccurate.
A notable feature of this case series was that medical
management protocols routinely consisted of an initial
two- to three-week treatment period before EFI1, during
which time most dogs received oral prednisolone and no
topical or oral antifungal treatment. Early therapy was
concentrated more on reversing soft tissue changes secondary to inflammation26 than specifically addressing the
Malassezia overgrowth/infection. This also may be
explained by low clinician confidence in a topical mode of
delivery due to ear canal occlusion/stenosis or patient
aversion to treatment or therapeutic caution until the
extent of ear pathological findings and type of infection
were known. After EFI1, prescription of antifungal ear
drops to most dogs indicates that impediments to topical
therapy were deemed less significant at that point.
By comparison, less than a third of cases were prescribed oral itraconazole after a diagnosis of MalOE, perhaps as a result of clinician concerns over the ability of
the drug to achieve effective concentrations in the ear
canal.27 The addition of oral itraconazole to the treatment
regimen, however, did not affect overall odds of treatment success in these MalOE cases. A successful outcome also was recorded for two dogs with MalOE
prescribed oral itraconazole in the absence of antifungal
ear drops. However, there is limited benefit in drawing
conclusions from such low treatment numbers.
The management priority for the cases in this series at
the time of entering the authors’ care was the chronic ear
pathological findings. Oral glucocorticoids (or ciclosporin)
and topical glucocorticoids used to reverse ear pathological findings can also be expected to have controlled primary inflammatory (allergic) ear disease, where present,
and thus contributed to treatment success. In the
authors’ practice, resolution of chronic MalOE typically is
followed by measures to identify and address primary
causes of otitis, and other strategies to prevent recurrence of infections. This aspect of ear disease management was not within the remit of this study, yet it was
noted that nearly half of the dogs showed evidence of an
allergic phenotype during their ear disease management.
This is within the lower range of figures reported previously,11,28,29 and likely to represent an underestimate as
a consequence of masking of signs during treatment.
There is a current lack of (detailed) evidence on the
effects of the nature of primary ear disease and of preventive management strategies on the long-term outcome of canine otitis.
Otitis cases in this study are unlikely to represent the
wider population of dogs with chronic Malassezia otitis, in
view of selection bias inherent to a referral service and
for dogs generally amenable to home treatment. However, in terms of age profile and unilateral versus bilateral
otitis presentation, the cases in this study match other
studies of chronic otitis17,30 and also field studies that
have not specifically enrolled chronic cases.9,20,21
5
Boone et al.
Together, spaniel and retriever breeds accounted for over
half of the affected dogs in this study and also those in
the hospital denominator population with otitis, similar to
recent findings from a European otitis treatment intervention study.10 However, retrievers had over three times
the odds of matching the study criteria, perhaps reflecting
a relative predisposition to Malassezia otitis over other
types of ear infections within this breed clade or higher
odds of retrievers over spaniels being diagnosed with
allergic skin disease.31,32
In around one fifth of affected ears in this study, concurrent Malassezia OM was diagnosed based upon otoscopic findings and sampling of middle ear content. This
procedure carries the potential for iatrogenic contamination of yeast from the ear canal into the tympanic cavity
and thereupon false diagnosis of MalOE/OM.33,34 The frequency of MalOE/OM in the present study, however, is
comparable to reports of OM diagnosed in dogs with
undefined, chronic OE using CT35 and MRI17 imaging.
However, both imaging modalities may fail to diagnose
cases of early OM when there are only minor pathological
findings in the tympanic cavity.17,36,37 It is notable that
only four of 14 ears judged by the clinician to have
MalOE/OM in this study, based on video-otoscopy and
bulla lavage, had evidence of soft tissue attenuating
material in the tympanic bulla on CT imaging. Integrity of
the tympanic membrane was not a reliable indicator for
status of middle ear disease (as proposed by Cole in
1998) and neither was absence of neurological signs38 or
duration of ear disease. It would seem that a multimodal
diagnostic approach may be required to investigate the
involvement of the middle ear in cases of chronic otitis.
This retrospective study documents a high success
rate in the resolution of cases of chronic canine Malassezia OE, previously unresponsive to primary care, with a
well-staged and intense medical treatment plan. It further
shows that clinicians should suspect concurrent Malassezia OM in around a fifth of affected ears.
Acknowledgements
We thank the clients and staff of the veterinary hospital
for their kind collaboration.
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Supporting Information
Additional Supporting Information may be found in the
online version of this article.
Table S1. Dog breeds and breed clades represented in
the study population (n = 59 dogs).
Table S2. Summary of clinical features of dogs with concurrent Malassezia OM (n = 9 dogs, n = 14 ears).
sume
Re
quente chez le chien. L’infection par la levure commensale, MalasContexte – L’otite externe (OE) est fre
sulter en une atteinte chronique qui ne re
pond pas aux traitements de presezia pachydermatis, peut re
re intention. Les infections chroniques d’OE peuvent e
^tre associe
es avec une otite moyenne (OM).
mie
ses/Objectifs – De
crire la gestion me
dicale, le suivi clinique et la fre
quence d’otite moyenne chez
Hypothe
pondant pas aux traitements de premie
re intention.
les chiens atteints d’otite a Malassezia et ne re
^pital ve
te
rinaire de re
fe
re
de Janvier 2007 Sujets – Cinquante neufs chiens d’un ho
a Septembre 2018.
riels et me
thodes – Une analyse re
trospective des donne
es me
dicales de chiens re
fe
re
s pour otite
Mate
s pour otite a Malassezia sans un ho
^pital ve
te
rinaire.
chronique et traite
sultats – L’OE chronique a Malassezia a e
te
traite
e avec succe
s dans 91% des oreilles, dans 87% de
Re
. Le temps moyen de re
solution e
tait de 27
ces cas avec une intervention de flushing auriculaire associe
jours. Ni la duree de l’otite, la presence de neutrophiles dans le contenu de la bulle ni l’administration
volution clinique. L’OM veloppe concomitamment dans
d’itraconazole oral n’affecte l’e
a Malassezia se de
17 % des oreilles.
es aident les cliniciens et les soignants des chiens
Conclusions et importance clinique – Ces donne
cisions adapte
es, en documentant que la plupart des cas d’otite atteints a prendre les de
a Malassezia non
solues avec les traitements de premie
re intention, peuvent e
^tre traite
es avec succe
s avec un plan de traire
termine
. Les otites moyennes ^tre suspecte
es
tement efficace intense et bien de
a Malassezia devaient e
me des oreilles atteintes.
dans un cinquie
Resumen
n – la otitis externa (OE) es un trastorno comu
n por la levadura
n en los perros. La infeccio
Introduccio
nica que no responde a la
comensal, Malassezia pachydermatis, puede resultar en una enfermedad cro
n primaria estandar. La OE infecciosa cro
nica puede estar asociada con la otitis media (OM).
atencio
tesis/Objetivo – describir el manejo me
dico, los resultados clınicos y la frecuencia de afectacio
n del
Hipo
n primaria.
oıdo medio, en perros con otitis por Malassezia que no respondıan a la atencio
Animales – Cincuenta y nueve perros de un hospital veterinario de referencia desde enero de 2007 hasta
septiembre de 2018.
todos y materiales – Analisis retrospectivo de historias clınicas de perros remitidos con otitis cro
nica y
Me
tratados por otitis por Malassezia en un hospital veterinario de referencia.
nica con Malassezia se trato
con e
xito en el 91% de los oıdos, en el 87% de estos
Resultados – la OE cro
n de lavado de oıdo. La mediana del tiempo de resolucio
n fue de 27 dıas. Ni la
casos con una intervencio
n de la otitis, ni la presencia de neutro
filos en la secrecio
n auditiva ni la administracio
n de itraconazol
duracio
oral afectaron el resultado clınico. Se observo OM concurrente por Malassezia en el 17% de los oıdos.
Conclusiones y relevancia clınica – estos hallazgos ayudan a los veterinarios y cuidadores de perros afectados en la toma de decisiones, al documentar que la mayorıa de los casos de otitis canina por Malassezia
n primaria est
xito con un tratamiento
que no se han resuelto con la atencio
andar pueden tratarse con e
dico intenso y bien organizado. Se debe tener en cuenta que la OM por Malassezia ocurre de forma conme
currente en alrededor de una quinta parte de los oıdos afectados.
Zusammenfassung
Hintergrund – Otitis externa (OE) ist eine h€
aufige Erkrankung bei Hunden. Eine Infektion mit begleitenden
€nnte in einer chronischen Erkrankung resultieren, die mit einer
Hefen, Malassezia pachydermatis, ko
© 2021 ESVD and ACVD, Veterinary Dermatology
7
Boone et al.
€se
standardisierten Prim€artherapie nicht mehr erfolgreich behandelt werden kann. Eine chronische infektio
OE kann mit einer Otitis media (OM) im Zusammenhang stehen.
€ber die medizinische Behandlung, den klinischen Erfolg und die H€
Hypothese/Ziel – Ein Bericht u
aufigkeit
der Mittelohrbeteiligung bei Hunden mit einer Malassezia Otitis, die auf eine Prim€
arbehandlung nicht
ansprach.
€
€nfzig Hunde aus einer Uberweisungsklinik
€ber einen Zeitraum von J€
Tiere – Neunundfu
u
anner 2007 bis
September 2018.
Methoden und Materialien – Eine retrospektive Analyse der medizinischen Daten der Hunde, die wegen
€
€berwiesen wurden und wegen einer Malassezia Otitis in einer Uberweisungsklieiner chronischen Otitis u
nik behandelt worden waren.
Ergebnisse – Eine chronische Malassezia OE wurde bei 91% der Ohren erfolgreich behandelt, wobei in
€tig war. Die mediane Zeit bis zur Heilung lag bei 27 Tagen. Weder die
€lung no
87% dieser F€alle eine Ohrspu
Dauer der Otitis, noch das Auftreten von Neutrophilen im Ohrausfluss noch die Verabreichung von Itrakonazol per os beeinflussten den klinischen Erfolg. In 17% der Ohren trat eine Malassezia OM gleichzeitig auf.
Schlussfolgerungen und klinische Bedeutung – Diese Ergebnisse helfen KlinikerInnen und Pflegenden
von betroffenen Hunden beim Treffen von Entscheidungen durch die Dokumentation der Tatsache, dass die
meisten F€alle einer caninen Malassezia Otitis, die sich durch eine prim€
are Standardtherapie nicht verbesserten, erfolgreich mit einem gut ausgew€ahlten und intensivem medizinischen Behandlungsplan behandelt
€nnen. Bei einem Fu
€nftel der betroffenen Ohren sollte der Verdacht auf eine gleichzeitig auftrewerden ko
tende Malassezia OM bestehen.
要約
背景 – 外耳道炎 (OE) は犬によく見られる疾患である。常在酵母であるMalassezia pachydermatisに感染する
と、標準的な一次治療に反応しない慢性疾患になることがある。慢性感染性OEは、中耳炎 (OM) を伴う
ことがある。
仮説/目的 – 本研究の目的は、プライマリーケアに反応しないMalassezia耳炎の犬における医学的管理、臨
床結果および中耳病変の頻度を報告することであった。
供試動物 – 2007年1月から2018年9月まで、1つの紹介動物病院からの59頭の犬。
材料と方法 – 紹介元の動物病院で慢性耳炎として紹介され、マラセチア耳炎の治療を受けた犬の診療記
録を回顧的に解析した。
結果 – 慢性マラセチア耳炎は91%の耳で治療が成功し、そのうち87%の症例では1回の耳洗浄の介入で済
んだ。治癒までの期間の中央値は27日であった。耳炎の期間、耳垢中の好中球の存在、イトラコナゾー
ルの経口投与は臨床結果に影響しなかった。17%の耳にマラセチアによる中耳炎が併発していた。
結論と臨床的妥当性 – これらの知見は、標準的な一次治療で治癒しなかった犬のマラセチア耳炎のほと
んどの症例が、十分に段階を踏んだ集中的な内科的治療計画によって成功裏に治療できることを証明す
ることで、罹患した犬の臨床家や介護者の意思決定を助けるものである。マラセチア中耳炎は、罹患耳
の約1/5で同時に発症していることを疑うべきである。
摘要
背景 – 外耳炎(OE)是犬的常见疾病。被共生酵母菌——厚皮马拉色菌感染, 对初级常规治疗无效, 可能导致
慢性疾病。慢性感染性OE可能导致中耳炎(OM)。
假设/目的 – 报告对常规治疗无效的马拉色菌耳炎患犬的医疗管理、临床效果和中耳发病率。
动物 – 2007年1月至2018年9月, 一家转诊兽医医院的59只犬。
方法和材料 – 转诊的治疗过马拉色菌耳炎的慢性耳炎患犬, 回顾性分析其在转诊兽医医院接受治疗的病
历。
结果 – 成功治疗了慢性马拉色菌OE中91%的耳朵, 其中87%的病例进行了单耳冲洗干预。中位消退时间为
27天。耳炎持续时间、耳分泌物中存在中性粒细胞或口服伊曲康唑均不影响临床效果。17%的耳朵同时发
生马拉色菌OM。
结论和临床相关性 – 初级常规治疗无效的犬马拉色菌耳炎病例, 经过合理分期和有力的药物治疗计划,大部
分得以成功治疗, 这些记录发现有助于临床医生和护理者对病犬做更好的决策。应怀疑约五分之一的患耳并
发马拉色菌OM。
Resumo
uma doencßa comum em c~
Contexto – A otite externa (OE) e
aes. Infeccß~
ao pela levedura comensal Malas^nica que n~
sezia pachydermatis, pode resultar em doencßa cro
ao responde aos tratamentos de primeira
^nica pode estar associada dia (OM).
escolha. A OE cro
a otite me
tese/Objetivo – Relatar a conduta clınica, evolucß~
^ncia de envolvimento da orelha me
dia,
Hipo
ao e freque
em c~aes com otite por Malassezia n~ao responsiva ao tratamento prim
ario.
^ncia entre janeiro de
Animais – Cinquenta e nove c~aes atendidos em um hospital veterin
ario de refere
2007 e setembro de 2018.
todos e materiais – Analise retrospectiva dos prontu
^nica e
Me
arios de c~
aes encaminhados com otite cro
^ncia.
tratados para otite por Malassezia em um hospital veterin
ario de refere
8
© 2021 ESVD and ACVD, Veterinary Dermatology
Clinical outcomes Malassezia otitis
^nica por Malassezia foi tratada satisfatoriamente em 91% das orelhas, em 87%
Resultados – A OE cro
tica. O tempo me
dio de resolucß~
destes casos com apenas uma lavagem o
ao foi de 27 dias. N~
ao houve alterfilos na secrecß~
acß~ao na evolucß~ao do quadro de acordo com a duracß~
ao da otite, presencßa de neutro
ao auricular bem como administracß~ao de itraconazol por via oral.
~ es e releva
^ncia clınica – Esses achados auxiliam os me
dicos veterin
Concluso
arios e cuidadores de c~
aes
~es, pois foi capaz de demonstrar que a maioria dos casos de otite por Malasafetados na tomada de deciso
sezia canina que n~ao se resolvem com os cuidados prim
arios padr~
ao, podem ser tratados com sucesso utilizando um protocolo de tratamento intenso e bem organizado. A OM por Malassezia ocorre
simultaneamente em cerca de um quinto das orelhas afetadas.
© 2021 ESVD and ACVD, Veterinary Dermatology
9