Bacterial and Fungal Skin Diseases Flashcards
which bacteria can cause superficial lesions?
S. pseudintermedius
S. aureus
S. schleiferi
what are the main primary lesions that indicate pyoderma?
pustules
abscesses
epidermal collarettes
does presence of bacteria on the skin mean pyoderma?
no
can a positive skin culture diagnose pyoderma?
no
when is culture and sensitivity mandatory?
if you see rods in cytology
pyoderma does not respond to antibiotics
patient’s history is suggestive of resistant infection
deep pyoderma
what is the best treatment option for superficial pyoderma?
only topical
what is benzoyl peroxide?
potent antibacterial and mild antifungal
which antibiotics are the first line for pyoderma?
first generation cephalosporins: cephalexin
amoxicillin-clavulanate
clindamycin
how long should you teat with antibiotics for superficial pyoderma?
2-4 weeks
what does treatment success of pyoderma depend on?
underlying conditional control: most important
appropriate antibiotic or topicals
dose
duration
if you diagnose pyoderma, and there are no signs of underlying disease present, what should you do?
treat pyoderma and wait for other signs
what diseases should you consider if there are no signs of underlying disease in an animal with pyoderma?
flea allergy
hypothyroidism
seasonal allergies
demodicosis
subclinical allergies
what does impetigo look like?
superficial non-pruritic pustules on ventral abdomen
who is bacterial folliculitis common in?
short coated breeds
what is bacterial folliculitis most commonly secondary to?
demodicosis
allergies
what is exfoliative pyoderma associated with?
exfoliative toxins
what are lesions with furunculosis?
nodules
abscesses
plaques
draining tracts
what should you check for with podofurunculosis?
demodicosis
what is the most effective anti-inflammatory for podofurunculosis?
cyclosporine- modified
what is german shepherd pyoderma believed to be?
immune-mediated condition
hypersensitive inflammatory response toward minimal bacterial infection
if acute moist dermatitis/pyotraumatic dermatitis is on the cheeks or neck, what is it most likely from?
otitis
in which animals should you suspect dermatophytosis?
outdoor cat
recently acquired kitten/cat/puppy from shelter/street
what are the clinical signs of dermatophytosis?
focal spontaneous alopecia/scaling
no pruritus usually
more commonly face, ears, legs
can be generalized
long-haired may not have alopecia
kerion dogs
how can you diagnose dermatophytosis?
wood’s lamp
direct microscopy of skin scrapings/trichoscopy
tape cytology
cytology
culture
dermoscopy
PCR
skin biopsy
none can rule out 100%
what is a positive wood’s lamp test?
apple green fluorescence of hair shafts
is dermatophytosis self-limiting?
in immunocompetent animals
what are the topical treatments of dermatophytosis?
azoles: enilconazole, miconazole, ketoconazole
miconazole and chlorehexidine: synergism
lime sulfur
what is Malassezia?
commensal fungi
yeasts
what is the most common Malassezia in dogs and cats?
Malassezia pachydermatis
what are the common clinical signs of Malassezia?
brown discoloration
lichenification and hyperpigmentation
odor
greasy skin
pruritus
how can Malassezia be treated topically?
acetic acid
topical azoles
lime sulfur
chlorhexidine
what are the best options for systemic treatment of Malassezia dermatitis?
itraconazole
ketoconazole
posaconazole
how long should you treat for Malassezia dermatitis?
2-4 weeks
which bacteria can cause both superficial and deep bacterial infections?
S. pseudintermedius
S. aureus
S. schleiferi
what secondary lesions go with pyoderma?
crusts
epidermal collarettes
multifocal spontaneous alopecia
draining tracts
erosions
ulcers
how can you diagnose pyoderma?
pyoderma lesions
cytology: neutrophils and bacteria
how can you treat deep pyoderma?
topical and systemic
systemic
4+ weeks
which topical pyoderma treatment does not penetrate well and postpones wound healing?
silver sulfadiazine cream
what are the second line antibiotics for pyoderma?
fluoroquinolones
doxycycline or minocycline
trimethoprim- and ormetoprim-potentiated sulfonamides
in who is impetigo common?
young puppies
how can you treat impetigo?
no systemic
topical treatment with improved hygiene is curative
what are the primary lesions in bacterial folliculitis?
papules and pustules
may be difficult to appreciate, confused with urticaria
what are the lesions with exfoliative pyoderma?
epidermal collarettes with or without spontaneous alopecia
what is podofurunculosis commonly associated with?
positional pododermatitis
what is positioning pododermatitis likely exacerbated by in short-coated breeds?
traumatic furunculosis
what is german shepherd pyoderma characterized by?
recurrent fast developing deep painful pyoderma/furunculosis
what is the most common pathogen of german shepherd pyoderma?
S. pseudintermedius
how can you treat acute moist dermatitis/hot spot/pyotraumatic dermatitis?
steroidss/apoquel for short time in superficial
antibacterial treatment
how is intertrigo/skin fold dermatitis treated?
mostly topically
may require oral antibiotics
may require surgical intervention
what are the causes of superficial fungal skin diseases?
dermatophytosis
malassezia dermatitis
what causes dermatophytosis?
Microsporum
Trichopyton
Epidermphyton
tropic to skin and hair keratin
what percentage of dermatophytosis in dogs and cats is Microsporum canis?
90%
is Microsporum canis a normal skin inhabitant?
no
where do dermatophytes form macroconidium?
only on medium
not in tissue
which animals are predisposed to dermatophytosis?
persian cats
yorkshire terriers
young or immuncompromised
why do we treat dermatophytosis?
shorten disease period
reduce risk of persistent or progressing infection
reduce risk of other pets/animals infection
reduce risk of people infection
what are some systemic antifungals?
itraconazole
terbinafine
fluconazole
ketoconazole
griseofulvin
lufenuron
what immune response do dermatophytes cause?
cellular and humoral immune response
what do Malassezia colonize?
epidermal surface
what are the virulence factors of Malassezia?
trypsin-sensitive proteins or glycoproteins
proteases, lipoxygenases
biofilm formation
lipase
phospholipasse
what areas are commonly affected by Malassezia?
ears
lip folds
interdigital areas and nailbeds
ventral neck
perianal area
chin
axillae groin
how can you diagnose Malassezia?
not culture
cytology: tape, impression, scraping, nailbed sampling
is Malassezia dermatitis always secondary?
yes
