Pyoderma Flashcards
pyoderma
pyogenic (pus producing) bacterial infection of the skin
does pyoderma occur more often in cats or dogs
dogs
stratum corneum is LESS effective at preventing bacterial invasion due to lack of an ostial (sebum) plug in the entrance of the hair follicle
how does disease alter the cutaneous microenvironment
alters the:
- pH
- humidity
- temperature
- lipids
- antimicrobial peptides
leads to an increased risk of pyoderma
most common pathogens in canine pyoderma
- staphylococcus pseudintermedius
- staphylococcus schleiferi
- staphylococcus aureus
what type of resistance can all strains of staph develop
methicillin resistance
is primary or secondary pyoderma most common
secondary - pyoderma associated with underlying disease or other predisposing factors
what are the most common predisposing factors to pyoderma
- pruritus (most common)
- inflammatory skin disease
- endocrinopathies (Cushing’s, hypothyroid)
- immunosuppression
- cornification disorders
- hair follicle diseases
- poor grooming, trauma
diagnosis of canine pyoderma
clinical signs: compatible skin lesions
cytology: evidence of bacterial invasion/proliferation
can monitor response to antimicrobial therapy
classification of pyoderma
depth of involvement and where the infection INITIATED
- surface
- superficial
- deep
surface pyoderma
starts in the stratum corneum
- pyotraumatic dermatitis
- intertrigo
- mucocutaneous pyoderma
superficial pyoderma
starts in the epidermis
- impetigo
- superficial folliculitis
deep pyoderma
starts in the dermis
- deep folliculitis & furunculosis
- cellulitis
whats the most common form of pyoderma in dogs
superficial folliculitis
what are the most common pathogens in feline pyoderma
- staph pseudointermedius
- staph schleiferi
- staph aureus
lesions associated with feline pyoderma
- miliary dermatitis
- papules
- scale
- collarettes
how to diagnose feline pyoderma
cytology
diagnosing superficial bacterial folliculitis
- clinical lesions - pustules, papules, collarettes
- cytology
- +/- culture and susceptibility
- +/- additional diagnostics
when is culture and susceptibility testing indicated
only if you suspect antibiotic resistance:
1. <50% reduction in lesions within 2 weeks of empiric antimicrobial therapy
2. new lesions still developing 2+ weeks after starting empiric antimicrobials
what should you sample for culture
- rupture intact pustules and culture the material
- underneath crusts
- edges of epidermal collarettes
- over surface of papules
treatment of superficial folliculitis
always do topical antimicrobials
+/- systemic antimicrobials
topical antimicrobial usage
chlorhexidine + azole antifungals (for synergistic effect)
use for
- localized lesions
- early/mild generalized lesions
- part of ongoing management to prevent recurrence
duration of topical antimicrobial therapy
continue for 7 days BEYOND clinical resolution
systemic antimicrobial usage
tier 1: empiric therapy
- clavamox, cefpodoxime, clindamycin, cephalexin, etc
tier 2: based on C&S only
- fluoroquinolones, doxycycline, chloramphenicol, rifampin, aminoglycosides
use for deep lesions only
duration of systemic antimicrobial therapy
superficial: 2-3 weeks + 1 week beyond clinical cure (4 weeks total)
deep: 4-6 weeks + 2 weeks beyond clinical cure (6 to 8 weeks total)
