Secondary Infections- Malassezia Dermatitis and Bacterial Pyoderma Flashcards
What organism is most commonly involved in bacterial pyoderma in the dog
Staphylococcus pseudointermedius**
What is the most common yeast involved in otitis externa and dermatitis in the dog
M. sympodialis and M. globosa
What is the proper duration of antibiotic therapy for canine superficial bacterial pyoderma
Continue tx 7-10 days beyond resolution of CS
What is the most reliable way to diagnose Malassezia dermatitis
Cytology
What two conditions are typically secondary to an underlying disorder?
Bacterial pyoderma and Malassezia dermatitis
What are the topical tx?
lime sulfur, Enilconazole, or Miconazole/Chlorohexidine shampoo – twice weekly
What is an opportunistic, unipolar budding, normal commensal org that has symbiotic relationship with staphylococcal orgs
Malassezia pachydermatis
Malassezia CS in cats
- Otitis externa – black, waxy discharge
- Chin acne
- Pododermatitis
- Generalized scary erythematous dermatitis
- Allergic dermatitis
but usually nooooooo clinical signs
• Check for FeLV and FIV
Malassezia CS in dogs
- Pruritus
- Erythema
- Scale/crust
- Dirty, greasy haircoat
- Seborrheic odor
- Oily or dry dermatitis
More ____ have CS with malassezia than ____
more dogs have CS than cats
Predisposing factors to Malassezia dermatitis
Keratinization disorders, inflammatory dz, allergic dermatitis, metabolic dz, usually have some underlying disorder
What are reasons to culture?
Cytology reveals mixed inf (rods, cocci), recurrent bacterial inf, poorly responsible bacterial inf, new lesion development while on abx, patient has hx of drug intolerance/reactions
Systemic therapy rules of thumb:
Minimum of 21 days
7-10 days beyond clinical cure
topical therapy is adjunctive
if deep- minimum of 6 weeks, 2 weeks beyond resolution of CS
High number of M. pachydermatis isolated from where in dogs?
Oral mucosa
Low numbers of M. pachydermatis isolated from where in dogs?
Skin
M. pachydermatis is isolated less frequently in dogs or cats?
Cats
Characteristics of Malassezia that cause disease:
Lipase and lipoxygenase 🡪 liberate FAs for nutrients and alter sebum
Proteinase, chondroitin-sulphatase, phospholipase, hyaluronidase 🡪 facilitate keratin invasion
What are the two main predisposing factors for Malassezia dermatitis??
Allergic dermatitis (atopy or food allergy) and metabolic diseases (Like Cushing’s)
Where is regional dermatitis from M. dermatitis?
Ventral neck, axillary area, inguinal area, lower lip folds, interdigital areas, paronychia (inf. of nail bed), perianal region, ventral tail fold
___ ____ are usually secondary to other issues/underlying issues
Bacterial pyoderma
Diagnosis of bacterial pyoderma-
CS/appearance of lesions, cytology and response to tx
What abx choice has efficacy against staph pseudointermedius?
3rd gen cephalosporins
Used of ___ tier abx is strongly discouraged to prevent resistance
3rd tier
