- To do treatment trial for malassezia dermatitis on 6 animals with 2 different drug groups containing 3 animals each for a period of 1 to 2 weeks.
- Group 1 – Ketoconazole
- Group 2 – Ketoconazole+ vinegar..
- yeasts fitting the description of Malassezia have been recognized on human skin since 1846.
- Their importance as members of the normal cutaneous biota and their role in disease continue to be prominent topics in human and veterinary medical literature.
- It is now generally accepted that Malassezia yeasts are commensal organisms of mammals and may also be associated with various cutaneous diseases.
- The predisposing factors and infectious properties of Malassezia are still a focus of research and debate.
- Malassezia pachydermatis, lipophilic yeast is a commensal on canine skin. Malassezia were originally identified by the French scientist Louis-Charles Malassez in the late 19th century.
- It becomes an opportunistic pathogen when normal cutaneous microclimate or host defence mechanisms are altered, favouring its growth to become pathogenic.
- Malassezia produce many enzymes including lipases and proteases which can contribute to cutaneous inflammation through proteolysis, lipolysis and changes in cutaneous pH.
- It has been implicated as a pathogen within the external ear canal but only recently it has been associated with dermatitis.
- The yeast maintains a symbiotic relationship with cutaneous Staphylococci, producing both mutually beneficial growth factors and a favorable micro environment. Concurrent pyoderma frequently complicates Malassezia.
- Due to their lipophilic nature, Malassezia species other than Malassezia pachydermatis
can be very challenging to culture. This difficulty may account for the initial confusion in classifying the organism (it was identified based on cytologic characteristics alone for over 50 years).
- These yeasts, previously known as Pityrosporum, are now classified in the genus Malassezia. The genus Malassezia is taxonomically located in the family Cryptococcaceae. Based on the structure of the yeast cell wall (laminar with distinctive spiraling ridges).
- Currently, seven species of Malassezia have been identified: pachydermatis, M.
furfur, M. sympodialis, M. globosa, M. obtusa, M. restricta, and M. slooffiae.
- The species are defined by morphologic, physiologic, and molecular differences.
- pachydermatis is usually isolated from animals, particularly carnivores. It is rarely identified on human skin but has been associated with fungal septicemia.
- Malassezia is a single cell yeast with a thick cell wall, individual cells areovoid to globular or cylindrical. Cells in the process of budding forms a charecteristic ‘Peanut’ to ‘Russian doll’ shaped.
- Malassezia can be recovered from 3 day old puppies,suggesting there is a early transfer by licking, grooming or from vagina.
- It is commenly found inear canals, anal sacs, interdigital skin & mucocutaneous junctions (lips, prepuce vagina, anus) of healthy animals.
- Malassezia yeasts colonise the superficial layers of epidermal & infundibular stratum corneum.
- The virulence factors for Malassezia yeasts have not been well defined. Zymogens from the cell wall of Malassezia are capable of activating the complement system and liberating C5a anaphylatoxin.
- Lipases and lipoxygenases produced by Malassezia can alter sebum and may help the yeasts utilize cutaneous lipids as nutrients. Malassezia produces an extracellular glycoprotein that may also contribute to virulence.
- Yeast adherence to the stratum corneum may be an important factor in skin colonization and infection.
- At this time, with the use of RNA sequencing, adherence assays, and electrophoretic protein profiles, there is no evidence that one strain of Malassezia is more pathogenic than another. These findings emphasize the opportunistic nature of Malassezia.
- The lack of association with biological activity & virulance suggests that malassezia is an oppurtunistic pathogen able to estabish wherever there is a permissive environment.
- Anatomical features (bodyfolds, pendulous lips, hairy feet),inflamation ,exudates and licking can create warm, moist microenvironment. .
- keratinizatiom defects and endocrine disorders may increase humidity,and alter the quantity and quality of sebum, although the relationship between sebum production and malassezia growth is unclear. furthermore,disruption to the stratum corneum by self-trauma, keratinization or metabolic defects could also allow malasssezia to establish.
- Basset hounds
- West highland
- white terriers
- Cocker spaniels
- Miniature poodles
- German shephered dogs
- Australians silky terriers
- English setters
- Malassezia does not invade the staratum corneum even so immune response to this organisams can be detected healthy on affected dogs.
- Atleast 14 different protien antigens have been identified.
- Dogs with malassezia dermatitis tend to recognise more antigens than healthy dogs, but no association bettween the pattern of recogniyion and any particular malassezia strain are virulance has been demonstrated.
- Affected dogs also have elevated serum lgA igG titres compared to healthy dogs but this does not appear to be protective.
Factors, which appear to favor the growth of this yeast, include
- Abnormal levels of ceruminous lipids (ear wax or saliva).
- Excess sebum production/ reduced sebum quality
- Summer months (high humidity and allergy season) – a seasonal increase in case number may be observed in geographical region where a noticeable change to warm, humid climatic condition is present.
- Abnormal cell-mediated immunity due to allergies (atopy, food allergy, flea allergy, contact allergy), and disrupted epidermal surface and concurrent dermatitis eg. Pyoderma and endocrinopathy,
- Alterations in normal microflora in the ear and skin due to concurrent antibiotic therapy
- An alkaline/basic (rather than neutral or acidic) skin
- Managemental conditions like frequent bathing, etc
- In dogs the disease is most often seen at anatomic sites that create a relatively warm, moist skin environment. Thus the interdigital skin, ventral neck, lip region, ear canal, axilla, groin and folded areas are most often affected.
- Malassezia pachydermatis can transiently colonise humans.colonization of staff members hands from pet dogs was the likely cause of M.pachydermatis associated septicaemia, meiningitis and urinary tract infections in an intensive care nursery..
- The yeast then persisted through patient-to-patient transmission.the elderly AIDS sufferers or patients undergoing chemotherapy may also be at risk.this underlies the need observe hygienic precautions when handling healthy animals as well as those affected by malassezia pachydermatis
- In dogs, Malassezia is also a common perpetuating factor of canine otitis externa and is characterized by pruritus and inflammation of the external ear canal and a yellow- brown waxy exudate.
- It has been proposed that pachydermatis acts as an allergen in some dogs. Morris and colleagues demonstrated that atopic dogs with cytologic evidence of Malassezia dermatitis had stronger wheal and flare reactions to Malassezia antigen than atopic dogs without evidence of Malassezia dermatitis.
5 most important cardinal signs to be looked in for the diagnosis of Malassezia dermatitis in a dog with pruritus and mal odour, in association in one or more of the following.
- Erythema – redness, produced by capillary congestion
- Scaling – visible flakes of abnormal or compacted epithelial cells
- Greasy or waxy exudate
- Hyperpigmentation – an increase in cutaneous pigmentation followed by chronic inflammation
- Lichenification – thickening of skin with exaggeration of normal skin markings.
- Clinical signs:
- The diagnosis is based on clinical signs, presence of elevated number of yeast in lesional skin and a clinical and mycological response to antifungal therapy.
- Laboratory examination of impression smear (cytology):
Cytology is quick, easy, cheap and non – invasive. Direct impression on to a glass slide is possible on accessible skin; it is helpful if the skin is very moist or waxy.
- Moist cotton swabs can be rubbed over the lesion and then gently rolled over glass slide. The smear of suspected material is then air dried and heat fixed
- Flood the slides with Loeffler’s alkaline Methylene blue and allowd to act for 2-4 minutes.
- Wash in water, blot and dry.
- Examine under oil immersion.
The yeast stains blue or purple. The individual yeast cells are ovoid to globular and in the process of budding forms the characteristic ‘peanut’ to ‘Russian doll’ shape.
Benchmark in diagnosis includes the following:
- Five or more than 5 yeasts per high power magnification (x 100).
- Presence of characteristic peanut shaped Malassezia yeast cells (rarely seen in healthy skin but are readily identified in specimen from affected individual).
- Malassezia will grow on Sabouraud’s medium / Modified Dixon’s agar. Plates should be kept in contact with the skin for 5-10 seconds, and then cultured at 32-370 C for 3-7 days. Colonies are small, cream to yellow, dome shaped, smooth to slightly wrinkled with a regular to slightly lobed edge. However, as Malassezia organisms are commensal, isolation is not necessarily significant.
- The histopathology of Malassezia dermatitis is characterized by acanthosis, hyperkeratosis, and a superficial inflammatory infiltrate.
- Several topical and systemic treatment options are available to treat Malassezia
- Topical therapy
The yeast is located in stratum corneum and thus topical therapy alone can be successful when potent antifungal agents are promptly applied. Topical therapy avoids the expense and potential toxicity of systemic azole drugs and is considered as the most cost effective and safe treatment of dogs.
|Miconazole 2%, Chlorhexidine 2% shampoo||Excellent antibacterial and antifungal; residual activity|
|Selenium sulfide (1 %) shampoo||Good antifungal and keratolytic agent|
|Chlorhexidine scrubs (1-4 %)||Good antibacterial and antifungal; residual activity|
|Enilconazole rinse||Good antifungal agent|
As on date the best treatment for yeast and Staphylococcal infections is to alter the pH of the dog skin to make it more acidic.
A solution of equal parts of white vinegar and water (with a pinch of Boric acid), an inexpensive acidifying topical agent shall be applied to the skin of dogs and should be allowed to dry for good results. This can be repeated daily for a week period followed by shampoo bath (Antifungal and Antibacterial) at weekly interval.
- Systemic Therapy
When topical therapy is impractical or ineffective, systemic triazole antifungals can be used.
Drugs for systemic therapy of Malassezia infection in dogs
|Drug||Dose (mg/kg)||Route||Interval (hrs)||Duration
|Ketoconazole||5-10||PO||12-24||2-4||Tab. Petoral – K 200 mg
Tab. Ketopet 200 mg
|Itraconazole ( daily therapy)
Itraconazole (Pulse treatment)
|5-10||PO||24||2-4||Cap. Sporanox 100 mg|
|10||PO||First two days of each week for 2 – 4 weeks.|
Clinical improvement should be obvious after 7-14 days after treatment although treatment should be continued for another 7-14 days beyond clinical cure. Maintenance doses two to three times weekly may be necessary in certain cases. Itraconazole is better tolerated than Ketoconazole.
Performa for Malassezia Dermatitis
Case number: Date:
|Animal details||Owner details|
|Color :||Phone no:|
Onset of Problem first noticed: Sudden/Slow
Is it a year round: Yes/No
If seasonal influence: Summer/Winter
Where did problem begin:
Does animal Scratch:- Yes/No
- Frequency: Constant/Sporadic/Night
Are other animals or people affected: Yes/No
Animal’s environment : Outside ( %)/Inside ( %)
Animal’s diet: Veg/Non-Veg
Previous treatment, if any:
Other illness of animal:
Frequency of bathing: shampoo used:
Distribution of lesions:- Dorsal / Ventral
Primary lesions: Bulla/macule/nodule/papule/patch/plaque/pustule/tumour/vesicle/wheal
Secondary lesions: abcess/alopecia/callus/comedone/crest/cyst/epidermal collaratte/erosion/erythema/excoriation/fissure/hyperkeratosis/hyperpigmentation/hypopigmentation/lichenification/scale/scar/ulcer
Quality of hair coat: Dry/brittle/dull/oily
- Cytology (impression smear): +/-
- of org./field:
- Presence of dumb bell shaped organisms:
Group 1 (Ketoconazole)
|Drug||Dose (mg/kg)||Route||Interval (hrs)||Duration
|Ketoconazole||5-10||PO||12-24||2-4||Tab. Petoral – K 200 mg
Tab. Ketopet 200 mg
- Clinical improvement should be obvious after 7-14 days after treatment although treatment should be continued for another 7-14 days beyond clinical cure. Maintenance doses two to three times weekly may be necessary in certain cases.
- Absorption of Ketoconazole is improved when taken with meal or an acidic diet. Further antacids and H2 blockers should strictly be avoided.
|4519||Canine||Pug||Male||3months||Fawn||40 IU/L||22 IU/L|
|6876||Canine||Pug||Female||1.5years||Fawn||65 IU/L||37 IU/L|
|2580||Canine||Mongrel||Male||6years||White||48 IU/L||24 IU/ L|
- Adverse effects include anorexia, nausea, vomiting, diarrhea and elevated serum liver enzyme activities and hence Serum biochemistry to be monitored during therapy. Ketoconazole can also be teratogenic.
- SGPT & SGOT levels are taken before starting the treatment.
- Oral administration of ketoconazole alone gave a good respone im these 3 dogs, but taken upto 10 days or above to show the clinical improvement.
Group 2 (Ketoconazole+vinegar)
- As on date the best treatment for yeast and Staphylococcal infections is to alter the pH of the dog skin to make it more acidic.
- A solution of equal parts of white vinegar and water (with a pinch of Boric acid), an inexpensive acidifying topical agent shall be applied to the skin of dogs and should be allowed to dry for good results. This can be repeated daily for a week period followed by shampoo bath (Antifungal and Antibacterial) at weekly interval.
|842||Canine||Labrador Retriever||Male||4years||black||44 IU/L||24 IU/L|
|7470||Canine||Labrador Retriever||Female||2years||Fawn||20 IU/L||137 IU/L|
|654||Canine||Labrador Retriever||Female||6years||Fawn||70 IU/L||80 IU/L|
- Oral administration of ketoconazole combined with external application of vinegar gave best results, clinical improvements can be seen within a week.
- In the above treatment trial with Group1 (ketoconazole) & Group2 (Ketoconazole+vinegar).
- Group2 (Ketoconazole+vinegar) gave good results, the reasons are as follows
- Vinegar alters the pH of the skin, so it acts against both bacteria (Staphylococcus sp.) & fungi (Malassezia sp.) present on the skin surface.
- Vinegar directly acts on the organism present on the body surface. whereas ketoconazole is absorbed in the body via digestive tract, then acts on the organism.