Difference between revisions of "Malassezia Dermatitis"

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The degree of pruritus is variable but can be extreme especially on the face in a small number of dogs.  
 
The degree of pruritus is variable but can be extreme especially on the face in a small number of dogs.  
 
===Laboratory tests===
 
===Laboratory tests===
 +
The most common method of diagnosis is via microscopy of a tape strip which will yield an increased number of {{unfinished}}
 +
 +
==Introduction==
 +
Malasseszia Dermatitis is a skin disease associated with the yeast [[Malassezia pachydermitis|''Malassezia pachydermatis'']]. It is common in dogs but rare in cats. The yeast is found on skin and mucosal sites in healthy dogs and cats and under circumstances which remain poorly understood can proliferate and induce skin disease.
 +
 +
==Pathogenesis==
 +
''Malassezia pachydermitis'' proliferates and liberates enzymes and metabolites which induce cutaneous inflammation. Concurrent skin diseases such as [[Atopic dermatitis]] and primary defects of keratinisation are recognised in approximately 66% of cases. Some dogs may show hypersensitivity to ''Malassezia pachydermitis''.
 +
==Diagnosis==
 +
===History===
 +
Affected dogs usually present with° a greasy skin disease often with a characteristic odour and a variable degree of pruritus. Basset hounds, Cocker Spaniels and West Highland Terriers are predisposed.
 +
===Clinical signs===
 +
Malassezia dermatitis can complicate or mimic allergic skin disease and scaling skin disorders. The main clinical signs are erythema and a greasy exudate which may result in matted hair with variable amounts of alopecia and scaling. Hyperpigmentation and lichenification occur in chronic cases. Concurrent erythematous otitis externa with variable ceruminous discharge is common.
 +
The degree of pruritus is variable but can be extreme especially on the face in a small number of dogs.
 +
===Laboratory tests===
 +
The most common method of diagnosis is by microscopic examination of a tape stip reveealing an increased number of ''Malassezia pachydermitis''. Clear adhesive tape is applied to the affected area and removed, stained and examined under oil emersion. The yeast can also be cultured on Sabrouraud's dextrose agar at 32-37°C for 3-5 days.
 
==Treatment==
 
==Treatment==
 +
Treatment is aimed at reducing the yeast population and treatingany underlying skin conditions. The first choice of treatment is an antifungal medcated shampoo containing miconazole and chlorhexidine. Selenium sulphide in combination with enilconazole or ketoconazole can also be used topically but is less effective.The use of systemic antifungal drugs such as ketoconazole can also be considered. The response to treatment should be measured by clinical response and by a reduction in yeast populations on lsion skin upon microscopic examination.
 
==Literature Search==
 
==Literature Search==
 
==References==
 
==References==
 +
* Merck & Co (2008) '''The Merck Veterinary Manual (Eighth Edition)''' ''Merial''
 +
* Foster, A, and Foll, C. (2003) '''BSAVA small animal dermatology (second edition)''' '' British Small Animal Veterinary Association''
 +
* Bond, R, Hendricks, A. (2008) '''Veterinary Dermatology Integrated Bvetmed course notes''' Department of Veterinary Clinical Sciences and Patology and Infectious Disease. Royal Veterinary College, University of London.
  
**Regional lesions: muzzle, ears, interdigital, perianal
+
[[Category: To Do - Review]]
**Or generalised disease
 
**Erythematous, hyperpigmented, [[Skin Glossary - Pathology|lichenified]] and scaly lesions with alopecia
 
*Microscopically:
 
**[[Skin Glossary - Pathology|hyperkeratosis, parakeratosis]]
 
**Spongiotic pustular dermatitis
 
**[[Skin Glossary - Pathology|Acanthosis]]
 
**Organisms are usually present, minimum 3-5 yeasts per high-power field must be found to imply cause of disease
 
 
 
 
 
Grossly, regional lesions may be seen around the muzzle, [[Ear -  Anatomy & Physiology|ears]], interdigital, and perianal.  Other  common signs include erythema, hyperpigmentation, [[Skin Glossary -  Pathology|lichenified]] and scaly lesions with alopecia.
 
 
 
Microscopically,  one may see;[[Skin Glossary - Pathology|hyperkeratosis,  parakeratosis]], spongiotic pustular dermatitis, [[Skin Glossary -  Pathology|Acanthosis]].
 
 
 
[[Category: To Do - Dermatology]]
 

Revision as of 16:26, 22 November 2010



Introduction

Malasseszia Dermatitis is a skin disease associated with the yeast Malassezia pachydermatis. It is common in dogs but rare in cats. The yeast is found on skin and mucosal sites in healthy dogs and cats and under circumstances which remain poorly understood can proliferate and induce skin disease.

Pathogenesis

Malassezia pachydermitis proliferates and liberates enzymes and metabolites which induce cutaneous inflammation. Concurrent skin diseases such as Atopic dermatitis and primary defects of keratinisation are recognised in approximately 66% of cases. Some dogs may show hypersensitivity to Malassezia pachydermitis.

Diagnosis

History

Affected dogs usually present with a greasy skin disease often with a characteristic odour and a variable degree of pruritus. Basset hounds, Cocker Spaniels and West Highland Terriers are predisposed.

Clinical signs

Malassezia dermatitis can complicate or mimic allergic skin disease and scaling skin disorders. The main clinical signs are erythema and a greasy exudate which may result in matted hair with variable amounts of alopecia and scaling. Hyperpigmentation and lichenification occur in chronic cases. Concurrent erythematous otitis externa with variable ceruminous discharge is common. The degree of pruritus is variable but can be extreme especially on the face in a small number of dogs.

Laboratory tests

The most common method of diagnosis is via microscopy of a tape strip which will yield an increased number of


Introduction

Malasseszia Dermatitis is a skin disease associated with the yeast Malassezia pachydermatis. It is common in dogs but rare in cats. The yeast is found on skin and mucosal sites in healthy dogs and cats and under circumstances which remain poorly understood can proliferate and induce skin disease.

Pathogenesis

Malassezia pachydermitis proliferates and liberates enzymes and metabolites which induce cutaneous inflammation. Concurrent skin diseases such as Atopic dermatitis and primary defects of keratinisation are recognised in approximately 66% of cases. Some dogs may show hypersensitivity to Malassezia pachydermitis.

Diagnosis

History

Affected dogs usually present with° a greasy skin disease often with a characteristic odour and a variable degree of pruritus. Basset hounds, Cocker Spaniels and West Highland Terriers are predisposed.

Clinical signs

Malassezia dermatitis can complicate or mimic allergic skin disease and scaling skin disorders. The main clinical signs are erythema and a greasy exudate which may result in matted hair with variable amounts of alopecia and scaling. Hyperpigmentation and lichenification occur in chronic cases. Concurrent erythematous otitis externa with variable ceruminous discharge is common. The degree of pruritus is variable but can be extreme especially on the face in a small number of dogs.

Laboratory tests

The most common method of diagnosis is by microscopic examination of a tape stip reveealing an increased number of Malassezia pachydermitis. Clear adhesive tape is applied to the affected area and removed, stained and examined under oil emersion. The yeast can also be cultured on Sabrouraud's dextrose agar at 32-37°C for 3-5 days.

Treatment

Treatment is aimed at reducing the yeast population and treatingany underlying skin conditions. The first choice of treatment is an antifungal medcated shampoo containing miconazole and chlorhexidine. Selenium sulphide in combination with enilconazole or ketoconazole can also be used topically but is less effective.The use of systemic antifungal drugs such as ketoconazole can also be considered. The response to treatment should be measured by clinical response and by a reduction in yeast populations on lsion skin upon microscopic examination.

Literature Search

References

  • Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial
  • Foster, A, and Foll, C. (2003) BSAVA small animal dermatology (second edition) British Small Animal Veterinary Association
  • Bond, R, Hendricks, A. (2008) Veterinary Dermatology Integrated Bvetmed course notes Department of Veterinary Clinical Sciences and Patology and Infectious Disease. Royal Veterinary College, University of London.