Malassezia dermatitis
Malassezia pachydermatis and Staphylococcus pseudintermedius are already present on normal dog skin. Whenever the immune system is suppressed and/or the epidermal barrier is disrupted, microbial overgrowth can then occur. This can result in opportunistic skin infections, such as Malassezia dermatitis.1
As there is thought to be an interaction between Malassezia pachydermatis and Staphylococcus pseudintermedius, both will increase in numbers.2
1. Nuttall T. Malassezia dermatitis. In: BSAVA Manual of Canine and Feline Dermatology 3rd Edition, BSAVA 2012; 198-205
2. Miller W.H., Griffin C.E., Campbell K.L. Malassezia dermatitis. In: Muller and Kirk’s Small Animal Dermatology 7th Edition, Elsevier 2013; 243-249
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What causes Malassezia dermatitis?
A wide variety of conditions can cause this opportunistic overgrowth, including breed predisposition, a compromised immune system and/or a disrupted skin barrier.3
3. Nuttall T (2012) Malassezia dermatitis BSAVA Manual of canine and feline dermatology. 3rd edition, 198-205.
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Consequences
Malassezia dermatitis in dogs may be localized or generalized. Commonly affected areas include the face (ear canal and perioral skin), cutaneous folds (axillae, groin and ventral neck) and feet (interdigital skin and nail folds).
Clinical signs are variable and can include:
- Mild to severe pruritus
- Erythema
- Greasy exudation and scaling
- Alopecia
In generalized cases, an offensive and rancid odor is commonly reported. Malassezia should be considered in any cases of pruritic dermatitis4.
4. Nuttall T Malassezia dermatitis. In: BSAVA Manual of Canine and Feline Dermatology 3rd Edition, BSAVA 2012; 198-205.
Images copyright Sue Paterson MA VetMB DVD DipECVD MRCVS
Diagnosis
Direct observation of the organisms in elevated counts on lesional skin. Combined with:
"A good clinical and cytological response on appropriate antifungal therapy" 5
5. Negre A. et al (2009) Evidence-based veterinary dermatology: a systematic review of interventions for Malassezia dermatitis in dogs. Vet Dermatol 20: 1-12
Images copyright Dermcare-Vet Australia and Ariane Neuber DrMedVet CertVD Dip ECVD MRCVS
Control
A recent evidence-based literature review which evaluated studies on the topical antimicrobial treatment of skin infections with bacteria or yeast concluded that:
There is the highest level of evidence for efficacy of a shampoo containing 2% miconazole and 2% chlorhexidine against M. pachydermatis (COE I - good).6
Ensure underlying causes are identified and addressed where possible.
6. Mueller R, Bergvall K, Bensignor E and Bond R (2012) A review of topical therapy for skin infections with bacteria and yeast. Veterinary Dermatology 23: 330-362
Maintenance
Basic skin health and underlying disorders
Basic skin health
The skin is the largest organ of the body. With its high cell turnover and metabolic rate, it obviously requires sufficient supply of skin-supporting nutrients to maintain its structure, function and health.
Underlying disorders
Several diseases can lead to skin problems and infections, with nutrition well acknowledged as an important part of the management of these problems in cats and dogs.
- Food allergy necessitates the use of hypoallergenic diets based on either hydrolyzed or novel ingredients
- Atopic patients can benefit from high levels of omega-3 fatty acids which have shown to support skin condition in atopic dogs.7 Essential fatty acids can furthermore improve a compromised lipid skin barrier
- Endocrine disorders such as Cushing’s syndrome and hypothyroidism often have dermatological complications that may benefit from nutritional management
Restoration of compromised skin
Recovery of almost any type of compromised skin condition and of the skin barrier will require extra skin-supportive nutrients like essential fatty acids, zinc, selenium and vitamin A, E and B-complex. Diets with increased levels of these nutrients can contribute to a successful recovery of the skin and coat.
7. Baddaky-Taugbøl B et al. A randomised, controlled, double-blinded, multicentre study on the efficacy of a diet rich in fish oil and borage oil in the control of canine atopic dermatitis (2005).