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Effect of aromatherapy and apipuncture on Malassezia-related otitis externa in dogs

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Aromatherapy and apipuncture was evaluated for its efficacy on canine Malassezia-related otitis externa. Ten dogs with Malassezia-related otitis externa were used in the present study. The control group was treated with ketoconazole, and the experimental group was treated with aromatherapy (topical aroma-oil drop) and apipuncture (injection-acupuncture of apitoxin). Clinical scores of the control group after 2-week treatment (p < 0.01) revealed a significant decrease compared with scores of pre-treatment. Experimental group scores after 2-week treatment revealed a significant decrease compared with scores of pre-treatment (p < 0.05). In the control group, ALT levels were significantly increased in the 1-week treatment (p < 0.05) and the 2-week treatment (p < 0.01), compared with the pretreatment levels. The experimental group ALT levels did not significantly change after 1-week and the 2-week treatments, compared with pre-treatment. ALT levels of the experimental group after the 1-week treatment (p < 0.05) and the 2-week treatment (p < 0.01), was significantly lower than those of the control group. In conclusion, a combination therapy of apipuncture and topical aroma-oil drop is not hepatotoxic and similar to the effect of ketoconazole treatment for Malassezia-related otitis externa in dogs.
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J Vet Clin 29(6) : 470-473 (2012)
470
Effect of Aromatherapy and Apipuncture on Malassezia-related
Otitis Externa in Dogs
Jin-Cheol Shin1, Sang-Hun Kim2, Hyung-Jin Park1, Kyoung-Won Seo1 and Kun-Ho Song*1
1College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Korea
2Hanaro Animal Clinics, Daejeon 300-070, Korea
(Accepted: December 18, 2012)
Abstract : Aromatherapy and apipuncture was evaluated for its efficacy on canine Malassezia-related otitis externa.
Ten dogs with Malassezia-related otitis externa were used in the present study. The control group was treated with
ketoconazole, and the experimental group was treated with aromatherapy (topical aroma-oil drop) and apipuncture
(injection-acupuncture of apitoxin). Clinical scores of the control group after 2-week treatment (p< 0.01) revealed a
significant decrease compared with scores of pre-treatment. Experimental group scores after 2-week treatment revealed
a significant decrease compared with scores of pre-treatment (p< 0.05). In the control group, ALT levels were
significantly increased in the 1-week treatment (p< 0.05) and the 2-week treatment (p< 0.01), compared with the pre-
treatment levels. The experimental group ALT levels did not significantly change after 1-week and the 2-week treat-
ments, compared with pre-treatment. ALT levels of the experimental group after the 1-week treatment (p< 0.05) and
the 2-week treatment (p< 0.01), was significantly lower than those of the control group. In conclusion, a combination
therapy of apipuncture and topical aroma-oil drop is not hepatotoxic and similar to the effect of ketoconazole treatment
for Malassezia-related otitis externa in dogs.
Key words :apipuncture, aromatherapy, Malassezia spp., otitis externa, dog.
Introduction
Malassezia is broad-based, budding, Gram-positive, lipo-
philic yeast that is frequently a normal inhabitant of the
canine and feline external ear canal (6,10,14,19). In the
canine ear canal, attachment to the cornified epithelial cell of
Malassezia is mediated by lipids (17). M. spp. prefers the
auditory canal of dogs with lipid-rich earwax where it grows
rapidly (16). Although Malassezia organisms are typically
peanut-shaped, they may be globose or ellipsoidal. Mean
Malassezia counts per high-power dry field of 5 in the dog
and 12 in the cat are considered pathologic. Mean Malasse-
zia counts per high-power dry field of 2 in dog and cat are
considered normal (18). Malassezia infections tend to pro-
duce copious, dark brown exudates with a sweet odor.
Malassezia infections are a common cause of chronic otitis
externa and treatment failure of otitis externa. Marshal et al.
(15) reported that Malassezia spp. (82.8%) were isolated
from 116 otitic dogs.
Aroma oils have the various medical properties. Bergamot
oil and tea tree oil especially have a strong antifungal activity
(1,23), and apitoxin has strong anti-inflammatory, antibacte-
rial and antifungal effects (12). The present study was per-
formed in order to elucidate the therapeutic effect of a com-
bination of aromatherapy and apipuncture on Malassezia-
related otitis externa in dogs.
Materials and Methods
Animals
Client-owned ten dogs (six males and four females; age
range: 3 to 13 years; weight range: 2.4 to 8 kg) with Malasse-
zia-related otitis externa were used in the present study. The
dogs were divided into the control group (ketoconazole treat-
ment: 5dogs) and experimental groups (aromatherapy and
apipuncture treatment: 5dogs). All dogs were treated with
antihelminths and annual vaccination, and reared in the
indoor. No underlying disease such as atopic dermatisis and
food allergy was observed. No treatment received about oti-
tis externa and other diaseses. Severity of otitis externa were
severe in the control and experimental groups.
Diagnosis
Smears of external ear canal for cytologic evaluation were
collected with sterilized cotton-tipped swabs. Diff-Quik stain
was used for cytologic evaluation. Malassezia spp. was
detected by microscopic examination. To confirm the Malasse-
zia infections, the samples were inoculated on Sabouraud dex-
trose agar (SD agar®, Asan pharmaceutical, Korea) at 30oC
with an incubation period of 2-5 days and were identified by
1Corresponding author.
E-mail :songkh@cnu.ac.kr
Aromatherapy and Apipucture for Canine Otitis Externa 471
standard microbiological procedure. Each dog was re-evalu-
ated at pre, 1 week and 2 weeks after treatment.
Treatment
The control group was medicated with ketoconazole (Kas-
zol®, Cellat Pharm Korea; 10 mg/kg, PO, q12h) as an antifun-
gal agent. Experimental group was treated with aroma-oil and
apitoxin. Aroma-oil was blended following formula; 10 ml
base oil (sweet almond; Aromatherapy Products Ltd., UK),
0.3 ml bergamot (Citrus bergamia; Aromatherapy Products
Ltd., UK) and 0.2 ml tea tree (Melaleuca alternifolia; Aro-
matherapy Products Ltd., UK). Blended aroma-oil was
applied 0.1 ml to ear canal in twice daily for 2 weeks. The
dogs were injected with apitoxin solution in SI-19 (Ting Gong
acupoint) bilaterally. An apitoxin solution was made from 1
mg apitoxin (Apimelena®, Samyang Anipharm Co., Korea).
Apitoxin was diluted in 1 ml of normal saline and 0.1 ml of
this solution was mixed with 0.1 ml of 2% lidocaine hydro-
chloride (Lidocaine HCl 2% Inj®, Daihan Pharm Co., Korea),
and was diluted with normal saline (0.8 ml). The apitoxin
solution was injected 0.2 ml into SI-19 (Ting Gong acu-
point) with 24 hour intervals two days. All dogs’ ear canals
were cleaned using normal saline once in two days.
Clinical scores
Pruritus, cerumen, redness, odor and number of yeasts were
chosen as the score calculation elements, and each element
was divided into several phases (Table 1). Pruritus, cerumen,
redness and odor in clinical score elements were evaluated by
owners for objective estimation. Number of Malassezia was
evaluated organism in high power field (×400 magnification).
Adding these elements, a score of 15 is perfect. Changes of
clinical scores during the present study were recorded in pre-
treatment, 1 week and 2 weeks after treatment.
Blood analysis
Blood samples were collected from cephalic vein by veni-
puncture. Serum levels of alanine transperase (ALT), alkaline
phosphatase (ALKP), blood urea nitrogen (BUN), creatinine
and total protein (TP) were determined using blood analyzer
(VetTest 8008, IDEXX, USA). The blood analysis was deter-
mined before treatment, as well as 1 and 2 weeks after treat-
ment, respectively.
Statistical analysis
Statistical significance was estimated using Mann-Whit-
ney U of SPSS 12.0 K for Windows. A P value of < 0.05
was considered significant. Statistical significance compared
to pre-treatment group in the clinical scores and ALT levels,
and also statistical significance compared between control
and experimental groups in the ALT levels.
Results
Clinical score and signs
Clinical scoring on each inspection day are shown in Table
1. Clinical scores in the control and experimental groups
after treatment are shown in Fig 1. In the clinical scores of
the control group, the 2-week treatment revealed a signifi-
cant decrease in yeast infection compared with scores of pre-
treatment (p< 0.01). Likewise in the experimental group, the
2-week treatment revealed a significant decrease compared
with scores of pre-treatment (p< 0.05). There was no signif-
icant difference between control and experimental groups.
Blood analysis
Serum levels of ALT, ALKP, BUN, creatinine and TP were
determined using a blood analyzer. In the control group, ALT
levels increased significantly at the 1-week (p< 0.05) and the
Table 1. Clinical scores of the judged efficacy of a combination
of aromatherapy and apipuncture
Score calculation elements
Score Pruritus Cerumen Redness Odor No. of
Malassezia
0 No Little No No No
1 Mild Slight Mild Slight 1-4
2 Moderate Moderate Moderate Moderate 5-9
3 Severe Severe Severe Severe > 10
Fig 1. Clinical scores in the control and experimental groups
(mean ± SD), Statistical significance compared to pre-treatmen
t
group (ap<0.01,
bp< 0.05).
Fig 2. ALT levels in the control and experimental groups
(mean ± SD), Statistical significance compared to pre-treatmen
t
group (ap<0.05,
bp< 0.01), Statistical significance compared to
control group (*p< 0.05, **p< 0.01).
472 Jin-Cheol Shin, Sang-Hun Kim, Hyung-Jin Park, Kyoung-Won Seo and Kun-Ho Song
2-week (p< 0.01) exams, compared with those of pre-treat-
ment group. In the experimental group, ALT levels were not
significantly changed at the 1-week and the 2-week exams,
compared with those of pre-treatment group. Comparing the
two groups at the treatment exams, the experimental group’s
ALT levels were significantly lower than those of the control
group at the 1-week (p< 0.05) and the 2-week exams (p<
0.01), (Fig 2). There were no significant differences in levels
of ALKP, BUN, creatinine and TP between the control and
experimental groups.
Discussion
Carfachia et al. (2) reported that Malassezia yeasts were
isolated from 72.9% of the cats and from 57.3% of the dogs
with otitis externa. Malassezia spp. was frequently isolated
from animals under 5 years of age. Chon et al. (3) reported
that the higher prevalence of Malassezia spp. infection was
observed in pendulous ear dogs (49.1%) as compared to that
in the dogs with erect ears (23.6%).
Girão et al. (9) reported that 63.7% of the otitis specimens
showed typical Malassezia cells on cytological examination.
In samples taken from the healthy ears of dogs with unilat-
eral otitis, only 21.43% showed evidence of Malassezia.
Malassezia spp. was identified cytologically and culturally in
57.53%, 14.29% and 30.0% of samples from the ears of dogs
with otitis, from the healthy ears of dogs with unilateral oti-
tis and from the ears of healthy dogs with no otitis. In the
present study, Diff-Quik stain was used for cytologic evalua-
tion, and Malassezia spp. was detected by microscopic exam-
ination. We confirmed by all microscopic positive samples
on Sabouraud dextrose agar. The poodle was the most com-
mon breed (39.29%) in the group with otitis associated with
Malassezia spp. Like above findings, 8/10 dogs used in the
present study have pendulous ear. The breeds were 3 Malt-
ese, 4 Shih-Tzu and 1 Cocker Spaniel.
Some studies warn the possible zoonotic transmission of
Malassezia to human beings from infected dogs (4,11,13,14,
20). In a human neonatal intensive care unit, Malassezia spp.
was isolated from one or more clinical specimens. Malasse-
zia spp. was cultured from blood, central venous catheter
tips, urine, cerebrospinal fluid, eye discharge, ear discharge
and tracheal aspirate (13). There is a report of chronic inflam-
matory skin granuloma caused by a Malassezia-infected dog
(7). Therefore, it is important to diagnose correctly and treat
effectively a canine malasseziosis for public health.
A number of researchers have examined treatment of
Malassezia-related otitis externa in dogs. Morgan (18) reported
that ketoconazole is effective for Malassezia-related otitis
externa in dogs. Cole et al. (5) reported that neither ER (EDTA,
tromethamine, benzyl alcohol) nor H2O (purified water) had
any effect on the growth of Malassezia. ER + keto (EDTA,
tromethamine, benzyl alcohol, ketoconazole) was signifi-
cantly more effective in reducing Malassezia growth at all-
time points compared to both ER and H2O. Also, Nakano et
al. (21) injected 0.5 ml of beta-thujaplicin solution of 100 µg/
ml including DMSO 2% daily into both external ear canals
of 31 cases. The beta-thujaplicin eardrops were effective for
Malassezia-related otitis externa in dogs.
In this study, the control group was medicated with keto-
conazole as an antifungal agent. By the clinical scores of con-
trol group, the 2-week treatment revealed a significant de-
crease compared with scores of pre-treatment, but, ALT levels
significantly increased after 1-week and 2-week treatment in
this group, because ketoconazole has hepatic toxicity (22). In
the experimental group, the authors used apipuncture and aro-
matherapy that have been known to have antifungal effects.
The clinical scores of the apipuncture and aromatherapy
group, revealed a significant decrease at 1 and 2 weeks com-
pared with scores of pre-treatment. ALT levels remained
within normal range after treatment in this group. The results
showed that apipuncture and aromatherapy have no hepato-
toxicity in the present study. ALT levels in the experimental
group were significantly lower during the treatment period
than in the control group. Moreover, two dogs of control
group have persistent ALT elevation over the normal range
after the 2-week treatment. The results suggest that a combi-
nation therapy of apipuncture and topical aroma-oil drop is
not hepatotoxic, and similar to the effect of ketoconazole
treatment for Malassezia-related otitis externa in dogs. The
limitation of this study was not a lot of samples for Malasse-
zia-related otitis externa in dogs.
References
1. Bell KL. Aromatherapy for dogs. In: Holistic aromatherapy
for animals, Forres: Findhorn Press. 2002: 145-159.
2. Cafarchia C, Gallo SS, Capelli S, Otranto D. Occurrence and
population size of Malassezia spp. in the external ear canal of
dogs and cats both healthy and with otitis. Mycopathologia
2005; 160:143-149.
3. Chon SK, Park YJ, Kim HE, Kim NS. Prevalence of
Malassezia pachydermatis in canine otitis externa in Chonbuk.
J Vet Clin 2006; 23:1-5.
4. Chryssanthou E, Broberger U, Petrini B. Malassezia pachy-
dermatis fungaemia in a neonatal intensive care unit. Acta
Paediatr 2001; 90: 323-327.
5. Cole LK, Luu DH. Rajala-Schultz PJ, Meadows C, Torres
AH. In vitro activity of an ear rinse containing tromethamine,
EDTA, benzyl alcohol and 0.1% ketoconazole on Malassezia
organisms from dogs with otitis externa. Vet Dermatol 2007;
18:115-119.
6. Danny W, William H, Craig E. Disease of otitis externa.
In: Muller and Kirk’s Small animal dermatology. Philadel-
phia: Saunders. 1995: 927-943,
7. Fan YM, Huang WM, Li SF, Wu GF, Lai K, Chen RY.
Granulomatous skin infection caused by Malassezia pachy-
dermatis in a dog owner. Arch Dermatol 2006; 142: 1181-
1184.
8. Ginel PJ, Lucena R, Rodriguez JC, Ortega JA. Semiquan-
titative cytological evaluation of normal and pathological
samples from the external ear canal of dogs and cats. Vet
Dermatol 2002; 13: 151-156.
Aromatherapy and Apipucture for Canine Otitis Externa 473
9. Girão MD, Prado MR, Brilhante RS, Cordeiro RA, Monteiro
AJ, Sidrim JJ, Rocha MF. Malassezia pachydermatis isolated
from normal and diseased external ear canals in dogs: a
comparative analysis. Vet J 2006; 172; 544-548.
10. Gotthelf LN. Perpetuating factors and treatment of otitis
externa. In: Small animal ear diseases: an illustrated guide,
St. Louis: Elsevier. 2005: 173-201.
11. Gueho E, Simmons RB, Pruitt WR, Meyer SA, Ahearn DG.
Association of Malassezia pachydermatis with systemic infec-
tions of humans. J Clin Microbiol 1987; 25: 1789-1790.
12. Kim MH. The main component of bee venom. In: Bee
venom therapy and bee acupuncture therapy, Seoul: Korean
Education and Planning Co. 1992: 67-132.
13. Larocco M, Dorenbaum A, Robinson A, Pickering LK.
Recovery of Malassezia pachydermatis from eight infants in
a neonatal intensive care nursery: clinical and laboratory
features. Pediatr Infect Dis J 1988; 7: 398-401.
14. Lefebvre SL, Waltner-Toews D, Peregrine AS, Reid-Smith
R, Hodge L, Arroyo LG, Weese JS. Prevalence of zoonotic
agents in dogs visiting hospitalized people in Ontario: im-
plications for infection control. J Hosp Infect 2006; 62:
458-466.
15. Marshall MJ, Harris AM, Horne JE. The bacteriological and
clinical assessment of a new preparation of the treatment of
otitis externa in dogs and cats. J Small Anim Pract 1974;
15: 401-410.
16. Masuda A, Sukegawa T, Mizumoto N, Tani H, Miyamoto
T, Sasai K, Baba E. Study of lipid in the ear canal in
canine otitis externa with Malassezia pachydermatis. J Vet
Med Sci 2000; 62: 1177-1182.
17. Masuda A, Sukegawa T, Tani H, Miyamoto T, Sasai K,
Morikawa Y, Baba E. Attachment of Malassezia pachy-
dermatis to the ear dermal cells in canine otitis externa. J
Vet Med Sci 2001; 63: 667-669.
18. Morgan RV. Disease of external ear and pinna. In: Hand-
book of small animal practice, St. Louis: Saunders Elsevier.
2008: 1045-1050.
19. Morris DO. Malassezia dermatitis and otitis. Vet Clin North
Am Small Anim Pract 1999; 29: 1303-1310.
20. Morris DO. Malassezia pachydermatis carriage in dog
owners. Emerg Infect Dis 2005; 11: 83-88.
21. Nakano Y, Matsuo S, Tani H, Sasai K, Baba E. Therapeutic
effects of beta-thujaplicin eardrops on canine Malassezia-
related otitis externa. J Vet Med Sci 2006; 68: 373-374.
22. Plumb DC. Plumb’s veterinary drug handbook, 6th ed,
Ames: Blackwell Publishing. 2008: 695-700.
23. Scheon AM, Wynn SG. Aromatherapy. In: Complementary
and alternative veterinary medicine, St. Louis: Mosby. 1998:
561-578.
말라세지아성 외이염에 대한 아로마치료와 약침의 치료 효과
신진철1·김상훈2·박형진1·서경원1·송근호*1
1
충남대학교 수의과대학 , 2
하나로동물병원
요약:말라세지아성 외이염에 대한 아로마치료법 (아로마오일) 약침치료법 (아피톡신) 적용하여 임상증상 개선
효과를 알아보기 위해 연구를 실시하였다. 실험군 5두는 아로마치료와 약침을 실시하였고 대조군 5두는 케토코나
졸을 적용하였다 . 임상증상은 대조군과 실험군에서 치료 전에 비해 각각 치료 2 후에 유의성 있는 개선효과를
타내었다 (p<0.01, p< 0.05). ALT 수치는 대조군에서 치료 전에 비해 치료 1, 2 후에 각각 유의성 있는 증가
소견을 나타내었다 (p< 0.05, p< 0.01). 실험군의 ALT 수치의 변화는 대조군에 비해 치료 1 , 2 후에 각각
의성 있는 감소소견을 나타내었다 (p<0.05, p<0.01). 결론적으로 말라세지아성 외이염에 대한 아로마치료법 (아로마
오일) 약침치료법은 효과가 있으며 대조군에 비해 간독성은 적은 것으로 나타났다 .
주요어 :약침, 아로마치료 , 말라세지아, 외이염,
ResearchGate has not been able to resolve any citations for this publication.
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