Exam 2 - Folliculitis Flashcards
for deep pyoderma, what are the 3 categories of differentials you’re considering?
infectious - bacterial (common, staph & pseudomonas), fungal, protozoal, & viral
inflammatory - hypersensitivity, foreign bodies, reactive histiocytes, nodular panniculitis, sweet’s syndrome, & sterile eosinophilic dermatitis (weil’s syndrome)
neoplastic - follicular tumors, sebaceous gland tumors, cutaneous lymphoma, mast cell
what treatment recommendations are used for deep pyoderma?
adjunct topical therapy to decrease exudate
systemic abx - based off of C/S for a minimum of 6-8 weeks at least 2 weeks past clinical resolution of signs
what are the guidelines for topical therapy for an animal with MRSA/MRSP?
frequent bathing - every 24-48 hours (can resolve superficial pyoderma with bathing alone) but needs owner dedication
spray/leave on formulations - ability to decrease bathing & frequency & gives residual activity
what are some recommendations made for the owner’s health who’s pet has MRSA/MRSP?
keep any draining wounds covered, don’t let the animal lick your face or wounds, no sharing beds/towels/linens, & hold off on pet therapy/social activities
what recommendations are made for an owner managing a pet with MRSA/MRSP?
minimize contact with young/immunocompromised people, good hand hygiene, finish ALL ABX, rechecks are important, regularly pick up their stool/change their litter box, & wear gloves when applying topical treatment
what is the mechanism of methicillin-resistant staph aureus/pseudintermedius?
mecA gene - altered drug affinity for penicillin-binding protein 2a which leads to the resistance conferred to all b-lactam & cephalosporin abx
carried on a staphylococcal chromosome cassette (SCCmec)
what abx is MRSA unaffected by?
all beta lactam abx!!!!
penicillins, cephalosporins, carbapenems, methicillin (replaced by oxacillin)
what is folliculitis?
inflammation of hair follicles
what is the pathogenesis of furunculosis?
deep bacterial folliculitis that has follicular rupture (furunculosis) resulting in deep infection of the surrounding soft tissue & a foreign body response (pyogranuloma) to free keratin that has escaped the follicle (nidus for continued infection)
what is the primary pathogen involved in folliculitis/furunculosis?
s. pseudintermedius
other staph spp., pseudomonas, proteus, & e. coli
T/F: folliculitis/furunculosis infection tend to be secondary to other underlying disease
true
what is the most common underlying disease you should think of when an animal presents to you with folliculitis/furunculosis?
DEMODICOSIS
what are some recognized clinical forms of folliculitis & furunculosis?
nasal pyoderma
muzzle pyoderma
pedal folliculitis & furunculosis
callus/pressure point pyoderma
GSD pyoderma
post-grooming folliculitis & furunculosis
what is another name for muzzle pyoderma?
canine acne
when do we see nasal pyoderma occur? where on the nose are lesions seen?
secondary to trauma or insect bites
bridge of the nose - doesn’t affect the nasal planum
where are lesions of canine acne seen? what animals?
rostral chin & muzzle
young dogs, short-coated breeds with stout hair (boxers, dobermans, english bulldog, mastiff, great dane)
pyotraumatic folliculitis resembles what surface pyoderma?
hot spot
what dog breeds are most commonly affected by pyotraumatic folliculitis? where are lesions seen?
goldens & st bernards
cheek & neck
what do lesions of pyotraumatic folliculitis look like?
circumscribed erythematous plaques with surface oozing & excoriation, peripheral erythematous macules/plaques, or epidermal collarettes
recurrence is common
T/F: pedal folliculitis & furunculosis is a common & frustrating skin disease that affects single/multiple paws on any haired surface with short-coated breeds with ‘stout’ hair may be over-represented (dachshund, english bulldog, boxer, mastiff, bullmastiff)
true
what clinical signs may be seen alongside pedal folliculitis & furunculosis?
may see hemorrhagic interdigital bulla/cysts
local lymphadenomegaly & pain manifests as lameness
what is the problem with using antibiotics for treating pedal folliculitis/furunculosis?
scarring from the disease prohibits the penetration of antibiotics & also tissue drainage
where do lesions of GSD pyoderma start?
haunches & ventral abdomen
what lesions are seen in GSD pyoderma?
stinky, painful
erythematous papules/pustules, furuncles, ulcers, draining tracts, severe devitalized necrotic skin, surface oozing severely adhered crusts forming ‘plates of armor,’ celluitis, scarring, & hyperpigmentation
how is GSD pyoderma diagnosed?
skin cultures!!!!!!!! clip & clean these dogs under heavy sedation/general anesthesia after diagnostic samples are taken
why does callus/pressure point pyoderma occur?
repeated trauma to calluses over bony prominences - especially on the elbow, hock, sternum, tuberosities of the pelvis, stifle, lateral digits - common to see comodones observed within the callus
what animals are commonly affected by callus/pressure point pyoderma?
large breed & giant breed dogs
also, sternum of dachshunds
T/F: GSD pyoderma is specific to middle-aged GSDs & their crosses & they typically have underlying diseases such as demodicosis, allergic skin disease, & endocrinopathies
true
what is the pathogenesis of post-grooming furunculosis?
associated with recent bathing/grooming against the direction of hair growth which traumatically causes hair to penetrate through follicular epithelium (shampoo and/or grooming instruments may be contaminated)
what lesions are seen with post-grooming furunculosis?
painful erythematous pustules, hemorrhagic bullae, nodules, & draining tracts along the dorsal back
what is your major differential to consider for deep pyoderma?
demodicosis
how is folliculitis/furunculosis diagnosed?
history, clinical signs, & exclude differentials
cytology - suppurative to pyogranulomatous inflammation with cocci or mixed infection
culture - ALWAYS CULTURE DEEP PYODERMA
skin scrapes - rule out demodicosis
biopsy - suppurative to pyogranulomatous nodular to diffuse dermatitis with folliculitis & furunculosis
what treatment is recommended for folliculitis/furunculosis?
topical therapy - avoid products containing alcohol
systemic abx - based off of c/s, for 6-8 weeks, & avoid concurrent use of glucocorticoids
what is cellulitis? what is the pathogenesis of it?
deep & rapidly spreading bacterial infection that is poorly demarcated & dissects through tissue planes of the dermis & subcutis
evolves from deep bacterial folliculitis & furunculosis in dogs or puncture (including bites) wounds in dogs & cats
what lesions are seen with cellulitis?
edematous boggy & gelatinous deep plaques with oozing from devitalized tissue
what should you always look for in an animal with cellulitis?
demodicosis
what differentials should be considered for an animal with cellulitis?
subcutaneous & deep mycosis, sterile nodular panniculitis, & neoplasia
how is cellulitis diagnosed?
skin culture - aspiration or deep tissue biopsy!!!!
what treatment is indicated for cellulitis from a cat-bite or dog-fight?
appropriate to empirically treat!!!!
lance it
clean with an antiseptic solution & rinse it well
+/- systemic abx for 14-21 days if poorly drained
what therapy is indicated for treating cellulitis?
topical therapy - bathing & whirlpool therapy
systemic abx based off of c/s for 8+ weeks
potential need for sx debridement
what is the pathogenesis of acral lick dermatitis?
results from chronic licking due to pruritus, pain, and/or psychological/behavioral disorders (boredom, attention seeking, confinement, loneliness, separation anxiety)
what animals are commonly affected by acral lick granulomas?
males often more affected
medium to large/giant breeds with shorter coats (dobermans, great dane, labs, goldens, GSD, weimaraner)
T/F: acral lick granulomas are always infected regardless of what the skin surface looks like
true
what are some underlying primary causes of acral lick granulomas?
allergic skin disease, demodicosis, infection (bacterial/fungal), trauma, foreign body, musculoskeletal disease, neuropathy, hypothyroidism, & psychological disorders/stress
what is the common lesion distribution seen in acral lick granulomas?
usually unilateral bony prominences with cranial/dorsal carpus as the most common site
metacarpus, tarsus, & metatarsal regions
what lesions are seen with acral lick granulomas?
firm, thick, alopecia, erosive to ulcerative, well-delineated plaque with a hyperpigmented periphery
what are some differentials you should consider for a patient with an acral lick granuloma?
folliculitis, callus, infectious granuloma, & neoplasia
what diagnostic test is recommended for all acral lick granulomas? how is it performed?
what others are recommended?
culture!!!!! tissue culture & aseptic biopsy - remove the epidermis & submit the dermis
history, rads if very swollen, & any other diagnostics needed to identify the underlying cause
T/F: acral lick granulomas are rarely a primary behavior disorder
true
when is it okay to use topical therapy for acral lick granulomas?
only if it doesn’t re-enforce the animal’s behavior to lick
what therapy is recommended for treating acral lick dermatitis?
identify & treat primary underlying cause
treat secondary deep pyoderma with antibiotics selected based off of culture & sensitivity (6-8 weeks)
provide options for more normal behavior - behavior modification, leash walks, behavioral pharmacology
barrier therapy
topical therapy as long as it doesn’t re-enforce the behavior
what lesion is pictured here?
acral lick granuloma
what are the main causes of folliculitis in the dog & cat?
superficial bacterial pyoderma - most common in dogs
demodicosis
dermatophytosis - most common in cats
can folliculitis occur on non-haired epithelium?
no
what is the major difference between juvenile onset demodicosis & adult onset demodicosis?
juvenile - doesn’t require treatment
adult - treatment is necessary
what is the general presentation of juvenile-onset demodicosis?
localized problem - 1-5 areas of patchy alopecia that is limited to one body region that is often associated with stress & may self-resolve within 4-8 weeks
what is the general presentation of adult-onset demodicosis?
generalized problem - more than 5 areas of patchy alopecia with 2+ regions or feet affected with short coated breeds being predisposed
T/F: in an animal with adult-onset demodicosis, you should consider the possibility of a genetic defect causing the problem or mites
true
adult-onset demodicosis is ALWAYS _________ & secondary to what?
generalized
secondary to an underlying disease process such as immunosuppression, neoplasia, endocrinopathy, or medications
lesion distribution shown here is characteristic of what skin condition? what is the common lesion distribution?
demodicosis
haired skin, perioral/periocular, head, & paws are all very common
how is demodicosis diagnosed?
easy to find on skin scraping if you’re scraping deep enough in multiple spots
minimum of scraping 4-6 spots, record areas sampled, & record mite numbers in different life stages & whether they are alive or dead
T/F: there is no juvenile onset demodicosis in cats
true
lesion distribution shown here is characteristic of what skin condition? what is the agent that causes it?
demodicosis in cats
demodex gatoi & demodex cati
what is the agent pictured? is it contagious?
demodex gatoi - YES CONTAGIOUS
demodex injai is a problem for what dogs? what does it cause?
WHWT, fox terriers
dorsal topline seborrheic dermatitis & occasionally intense facial pruritus
how is canine demodicosis classified?
based on the age of onset, extent of disease, & pathogenesis
what is the pathogenesis of juvenile-onset demodicosis?
aberration in host immune system (cell-mediated immunity)
associated with genetics/breeds, poor nutrition, & stress of varying causes
what is the pathogenesis of adult-onset demodicosis?
alteration in host immune system due to disease (allergic skin disease, hyperadrenocorticism, hypothyroidism, diabetes, neoplasia) or immunomodulatory therapies
mites proliferate in hair & cause folliculitis
what is the most difficult form of demodicosis to treat?
pododemodicosis
T/F: dogs with allergic skin disease have higher odds of having demodicosis than dogs without allergies
true
why is selective breeding necessary in regards to treating demodicosis?
selective breeding works to eliminate generalized juvenile-onset demodicosis from the canine population - do not breed sire, dam, or affected puppies
what are your main differentials for canine demodicosis?
bacterial folliculitis/superficial pyoderma
dermatophytosis
allergic skin disease
what diagnostics are needed apart from skin scrapes for adult-onset demodicosis?
CBC, chemistry, UA, fecal, heartworm testing, & MRD1/ABCB1-1 testing
why avoid miticidal therapy in juvenile-onset cases of demodicosis?
they have the potential for self cure & it poses an unnecessary risk
when are systemic antibiotics indicated for treating juvenile-onset demodicosis? what other treatments are used? how do you recheck?
if the animal also has superficial pyoderma, use for 3-4 weeks
topical therapy
recheck in 2-4 weeks to monitor resolution or progression
T/F: it is okay to use glucocorticoids in cases of juvenile-onset demodicosis
false - avoid using them
what is the goal of managing a patient with generalized demodicosis?
at least 2 consecutive negative skin scrapes obtained 4 weeks apart
what is a negative skin scrape in regards to demodicosis?
no mites of any developmental stage including dead mites or mite fragments
what is considered to be a complete disease cure in regards to generalized demodicosis?
no relapse of demodicosis for 1 year after drug discontinuation
T/F: administration of isoxazolines is not a valid reason to exclude demodicosis as a cause of alopecia & you still need to do a skin scrape to exclude it
true
why do we see treatment failure in cases of demodicosis?
failure due to:
-can’t control concurrent pyoderma
-failure to select appropriate therapy/failure to administer it at the correct dose/frequency/duration
-fail to identify/treat predisposing factors & conditions
-failure to monitor patient & adjust therapy accordingly
-failure to avoid the use of glucocorticoids & oclacitnib
RARELY EVER DUE TO RESISTANT MITES
all feline skin disease with alopecia as a feature should be considered suspect for what disease until proven otherwise?
dermatophytosis
what must be done for a DTM culture?
keep it at 25-30 C at >30% humidity
MONITOR DAILY FOR 21 DAYS
if you have an animal test positive in DTM for microsporum, what do you do next?
do a PCR!!!!!!!!
if it is positive - you have a diagnosis
if it is negative - pursue a culture
if you have an animal you suspect has trichophyton, what do you do next?
DTM - if negative, look at other differentials
if positive, do a culture
what are the biggest differences between dogs & cats in regards to dermatophytosis?
cats produce a large number of infective spores & distribute the spores over their entire body & shed numerous spores into their environment
what environmental decontamination is needed for a cat with dermatophytosis?
minimize stirring up spores with sweeping/dusting - swiffer clothes or damp moth
disinfection followed by 1:1 dilution bleach
confinement of infected cat
what adverse effect is associated with griseofulvin for treating dermatophytosis in cats?
bone marrow suppression
what adverse effect is associated with ketoconazole for treating dermatophytosis in cats?
hepatotoxicity - not well tolerated
what topical adjunct therapies are used for cats with dermatophytosis?
lime sulfur 3% solution & miconazole nitrate 2%/chlorhexidine gluconate 2%
used 1-2 times weekly
what systemic treatments are used for treating cats with dermatophytosis?
itraconazole 25mg/cat or 5-10mg/kg & terbinafine 30-40mg/kg
once daily for 30 days, then week on & then week off until cured
what is the benefit of using itraconazole or terbinafine for a cat with dermatophytosis?
it accumulates in the hair shaft & the medication persists for several weeks following discontinuation of treatment
ability to pulse dose patient
a cat with dermatophytosis will be ‘better’ before being cured - why?
there is a clinical cure prior to a mycological cure with average time to mycological cure of 6-8 weeks
cats are still potentially infective until mycological cure is reached
what treatment monitoring recommendations are made for cats with dermatophytosis?
continue treatment until you get 2-3 negative cultures
culture every 1-2 weeks
remember - 3 weeks needed to finalize cure
what lesions are associated with demodicosis?
spontaneous alopecia that is partial to complete & focal to diffuse
erythema, hyperpigmentation, scaling, lichenification, erosions, ulcers
what is pododemodicosis?
disease that specifically affects the paws causing pedal pruritus, pain, erythema, scaling, crusting, alopecia, hyperpigmentation, lichenification, pustules, hemorrhagic bulla, & draining tracts
possible fever & lymphadenopathy
what are some risk factors for dermatophytosis?
immunosuppression, over-crowding, environmental factors, age, genetics, poor grooming, trauma, & inflammation
what dermatophytes do not fluoresce?
microsporum gypseum & trichophyton mentagrophytes
what dermatophyte species fluoresces? is it zoophilic or geophilic?
microsporum canis
zoophilic
what dermatophyte species are zoophilic? which ones are geophilic?
zoophilic - microsporum canis & trichophyton mentagrophytes
geophilic - microsporum gypseum
how long do you have to treat an animal with generalized demodicosis?
must treat until you have 2-3 consecutive negative skin scrapes that are 2-4 weeks apart and are taken from the same site every time - absolutely no mites of any stage alive or dead should be seen
what products are used for treating demodex cati?
advantage multi
bravecto
revolution plus
what products are used for treating demodex gatoi?
advantage multi
bravecto
revolution plus
lime sulfur
what is the general mainstay therapy for treating generalized demodicosis?
nexguard/simparica/credelio every 3-4 weeks
bravecto every 2-3 months
T/F: in dogs, superficial alopecia doesn’t mean ringworm & is often over diagnosed
true
what dog breeds appear to be predisposed to dermatophytosis?
jack russell terriers & yorkies
what do you think this cat has?
dermatophytosis
is demodicosis a pruritic disease?
typically mild if present & often suggests concurrent bacterial folliculitis/pyoderma
what is the recommended therapy for treating generalized demodicosis?
bathe 1-2 times weekly
control for secondary pyoderma - b lactam abx
select miticidal therapy - bravecto, simparica, nexguard, credelio
perform 4-6 skin scrapes at the same site every 4 weeks
avoid spinosad use in dogs receiving extra label high doses of ivermectin, avermectins, or milbemycin
what is the mean duration of treatment for juvenile generalized demodicosis?
4.5 months
what is the mean duration of treatment for adult generalized demodicosis?
6 months
what was once the only approved treatment for canine demodicosis in the USA?
amitraz - MOA inhibitor & a2 agonist
what ingredients are in advantage multi that treat demodicosis?
imidocloprid + moxidectin
what ingredients are in bravecto that treat demodicosis?
isoxazolines - new standard of care for treating demodicosis, GABA gated chloride channel antagonist
what is dermatophytosis?
infection of keratinized structures such as the stratum corenum, air shaft, horn, claw, or nail in animals & man with fungi of the genera microsporum, trichophyton, & epidermophyton
T/F: dermatophytosis is 3x more present in FIV+ cats
true
what is the most common infectious skin disease of cats?
dermatophytosis
how do dogs get microsporum gypseum?
dogs digging & sticking their nose in soil
if a dog is positive for dermatophytosis, what should you search for?
infected asymptomatic cat at home
__________ is one of the few feline skin diseases that causes hyperpigmentation
dermatophytosis
T/F: if it looks like ringworm in the dog, it’s probably staph
true
what is the gold standard for diagnosing dermatophytosis?
DTM culture
T/F: topical spot therapy is successful for treating dermatophytosis
false - rarely if ever successful, you use it as adjunct therapy
how are lime sulfur dips used for treating dermatophytosis?
used 2x weekly - very effective, but stains porcelain/fabrics/jewelry
often used for 4-6 weeks
when should you start with topical therapy for an animal you suspect has dermatophytosis?
animal you have a high index of suspicion pending fungal culture
use on asymptomatic pets in the household pending fungal culture
young puppies/kittens
T/F: using topical body treatment in cats with dermatophytosis is rarely successful
true - use as adjunctive therapy
T/F: do not use systemic therapy in kittens/puppies until they are 8-12 weeks old unless the only other option is euthanasia
true
how long is therapy used for nodular dermatophytosis?
treated for 3-4 weeks beyond clinical remission & may require surgical removal
systemic therapy for dermatophytosis is often administered for how long?
6-12 weeks
why not use griseofulvin in FIV+ cats?
it causes severe neutropenia
what fungal agent do you suspect?
microsporum canis - 50% fluoresce
what fungal agent is pictured here?
microsporum canis
what fungal agent is pictured here?
microsporum gypseum
what fungal agent is pictured here?
trichophyton
