Derm Part 2 - lecture 7-12 Flashcards
what are the most common pathogens of bacterial pyoderma
staph pseudintermedius (dog)
staph aureus (cats)
true or false
pyodermas are never primary
true
what are the 4 types of bacterial pyoderma
intertrigo (skin fold dermatitis)
pyotraumatic dermatitis (hot spot)
superficial pyoderma
deep pyoderma
what is unique to pyotraumatic dermatitis “hot spots”? treatment?
no satellite lesion
2-4% chlorhexidine topical + treat underlying cause (i.e. flea hypersensitivity, otitis externa, allergies)
what is the cause of superficial pyoderma? treatment?
no identifiable underlying cause, folliculitis
topical therapy
differentials for folliculitis?
demodex
dermatophytosis
bacterial pyoderma
lesions associated with a deep bacterial pyoderma? treatment?
ulcers & hemorrhage
topical treatment but longer (4-6 weeks)
primary difference between the treatments of superficial and deep pyoderma?
superficial - treat 1 week past resolution
deep - treat 2 weeks past resolution
how to diagnose bacterial pyoderma?
cytology
staph will be cocci
E.coli, Pseudomonas, Corynebacterium will be rods
empirical therapy starters for bacterial pyoderma
1st gen cephs
clavamox
clindamycin
what is Malassezia Pachydermatis?
lipophilic budding yeast
commensal organism
secondary colonizer
NO immune suppression
Diagnosis of Malassezia Pachydermatis
moist/waxy areas = impression smear
dry areas = tape
stain with diff quick
examine in oil immersion
topical treatment for Malassezia Pachydermatis
shampoo, wipes, sprays, mousses w/ 2% chlorhexidine & 1-2% miconazole or ketoconazole
systemic treatments for Malassezia Pachydermatis
2-4 weeks of ketoconazole or terbinafine
what is the most common dermatophyte
microsporum canis
Microsporum canis natural host?
cats “stray kitten syndrome”
what is the most common lesion in dogs with dermatophytes
fungal kerion
if you see “rotten log” with spores around it, what do you suspect?
Microsporum canis
Diagnostics for dermatophytes? which is the gold standard?
woods lamp (30-80% fluoresce)
trichogram
culture (gold standard) on DTM
PCR
what do you expect to see on a positive dermatophyte culture?
red color change + white/beige growth
how can you speciate dermatophytes? are these found on the host?
macroconidia
do NOT grow on the host
dermatophyte treatment:
systemic (every +)?
topical (every + & every exposed)?
environmental?
systemic - itraconazole, terbinafine
topical - lime sulfur, imidazoles
environmental - clean
how long should you treat dermatophytes?
until two consecutive negative cultures taken 1-2 weeks apart
most common equine dermatophyte?
trichophyton equinum
phases of the hair cycle
anagen - growth
catagen - transition
telogen - rest
exogen - shed
how can you diagnose endocrinopathy alopecia?
NOT skin biopsy, need endocrine testing
how can you diagnose endocrine alopecia lookalikes?
skin biopsy!
what endocrinopathy might you see cutaneous atrophy, striae, phlebectasia, calcinosis cutis
Cushings
what endocrinopathy might you see alopecia over bridge of the nose, “rat tail”, nasal or paw pad hyperkeratosis, acanthosis, ceruminous otitis
hypothyroidism
what might you expect with endocrinopathy response to therapy?
worse before better
initial hair regrowth is darker
what endocrinopathy might you see with feminization, aspermatogenesis, prostatic disease and bone marrow hypoplasia?
sertoli cell tumor
what endocrinopathy might you see gynecomastia and abnormal estrus cycles?
cystic ovaries
if an owner is using topical estrogen cream, what might happen in their dog?
iatrogenic hyperestrogenism
what endocrinopathy lookalike do you suspect with a young Pomeranian with alopecia
Alopecia X
what endocrinopathy lookalike do you suspect with alopecia due to a severe illness/metabolic stress like fever, pregnancy, lactation, shock or drugs?
telogen effluvium
If a dog was recently clipped and surgically scrubbed and now has no hair regrowth, what endocrinopathy lookalike do you suspect? what are some treatments?
post clipping alopecia
low level laser
what endocrinopathy lookalike do you suspect with a boxer or bulldog with alopecia along flanks and lateral thorax? what might this also be associated with?
canine flank alopecia
seasonal - melatonin deficiency
treatment for canine flank alopecia?
melatonin therapy
low level laser
what endocrinopathy lookalike do you suspect with a young doberman or silver lab with alopecia in dilute areas of their coat?
color dilution alopecia
what weakens the hair shaft in color dilution alopecia?
macromelanosomes
what is an aquired pattern alopecia found in young dachshunds, boston terriers, chihuahuas and whippets? treatment?
pattern baldness
none - cosmetic
generalized findings with lupus (3)?
- interface dermatitis
- basal keratinocyte apoptosis
- dead reds w/ satellitosis
what is the most common lupus in small animals?
discoid lupus erythematosus
most common sites for discoid lupus erythematosus
nasal planum
pinna
perioral
what is the top differential for mucocutaneous lupus erythematosus? how would you differentiate?
mucocutaneous pyoderma - do cytology and look for bacteria
cytology, culture, treat for infection, biopsy if persists
what breed is vesicular cutaneous lupus erythematosus found in?
collies and shetland sheepdogs
what breed is exfoliative cutaneous lupus erythematosus found in?
german shorthair pointer due to autosomal recessive mutation
common findings with systemic lupus erythematosus
fever
polyarthritis
proteinuria
thrombocytopenia
discoid rash
what is the most specific ANA titer for SLE
nuclear ribonucleoprotein G (HnRNP G)
treatment for lupus?
immune suppression via…
tacrolimus 1% topical
doxy/niacinamide
steroids
non-steroidal immunosuppresives
apoquel
sunscreen
what is symmetric lupoid onychodystrophy?
idiopathic immunemediated disease that affects multiple nails
how do you diagnose symmetric lupoid onychodystrophy?
clinical signs bc biopsy requires amputation of P3
treatment for symmetric lupoid onychodystrophy?
slow & forever
pentoxifylline
fatty acids
cyclosporine
doxy/niacinamide
steroids
what is the most common autoimmune dermatologic disease in dogs and cats?
pemphigus foliaceus
difference between pemphigus foliaceus and vulgaris?
foliaceus = superficial
vulgaris = deep
pemphigus foliaceus predilection sites in dogs? cats?
dogs - pinna, paw pad, planum
cats - face, nail beds, nipples
autoantibodies target what in pemphigus foliaceus?
desmosomes = acantholytic keratinocytes
autoantibodies target what in pemphigus vulgaris?
hemidesmosomes = ulcerations
differentials for acantholytic keratinocytes
pemphigus foliaceus
bacterial pyoderma
dermatophytosis
how do you definitively diagnose pemphigus foliaceus?
biopsy
pemphigus vulgaris predilection sites?
oral
mucocutaneous junctions
paws
how do you definitively diagnose pemphigus vulgaris?
junctional biopsy
should see “tombstone effect”
pemphigus treatments
immunosuppression
steroids (first line)
cyclosporine (2nd)
