Exam 1 - FA Dermatologic Diseases Flashcards
what species are affected by pediculosis? which is most common of these?
cattle, sheep, goats, & llamas
goats
what is the causative of pediculosis?
sucking/biting lice
what environments are favorable for pediculosis?
winter & confined animals
what is the biggest difference between clinical signs of biting lice vs. sucking lice?
biting - pruritic
sucking - pruritic & anemia
how is pediculosis transmitted?
direct contact & fomites
how is pediculosis diagnosed?
exam the hair coat
why may I use ivermectin in an animal with pediculosis?
systemic medication to get the sucking lice!
T/F: topicals that are safe for cats are probably safe for camelids
true
what are your treatment options for pediculosis?
ivermectin & topical insecticides
what are the three main mites we see in food animals? which is most common?
psoroptic, chorioptic, & sarcoptic
chorioptic
what kind of mites affect sheep?
psoroptes ovis
what mites typically affect pigs?
sarcoptes
until proven otherwise, what mites are on small ruminants?
chorioptes
T/F: demodectic mites are rare in food animals
true
T/F: mites are relatively host-specific
true
what mites do not burrow?
psoroptes & chorioptes
what mite burrows?
sarcoptes
how are mites diagnosed?
skin scrapings & ear swabs
what mite has jointed pedicles?
psoroptes
what mites have non-jointed pedicles?
sarcoptes
what mites have short pedicles?
chorioptes
what sheep breed is most susceptible to psoroptic mange?
merino
T/F: psoroptes cuniculi is transmissible to humans
false
what is the life cycle of psoroptes cuniculi? why is this important?
2 week life cycle on the host but can survive in the environment for weeks
treat the environment too!!
are psoroptic mites pruritic?
yes
what are the clinical signs of psoroptic mange in sheep?
papules & crusts in wooled areas
intense pruritus - IgE vs mite antigens
secondary staph infections
what bug should you report in sheep???
psoroptic mange!!!
chorioptic mange typically causes lesions where?
legs/feet & often on scrotum/perineum
how is chorioptic mange diagnosed?
skin scrapings
is psoroptic or chorioptic mange more pruritic?
psoroptic
T/F: chorioptic mites only survive off the host for a few days
true
what is the treatment for chorioptic mange?
ivermectin for 3 weeks
topical treatment 2-3x a week
what mange is transmissible to humans?
sarcoptes scabei
what is the life cycle of scabies?
10-17 day life cycle
how does scabies progress?
starts at the head/ears/neck & then becomes generalized
T/F: scabies are burrowing mites that cause pruritus
true
T/F: a negative skin scrape for scabies doesn’t rule it out
true - small numbers are present & you may see it on a biopsy
how is scabies diagnosed?
can try a skin scrape & biopsy
often diagnosed based on clinical suspicion/response to treatment
how is scabies treated?
topicals or systemic ivermectin
what is an important differential for pruritic sheep!!
scrapie!!!
what is fly strike?
flies feed on open wounds with necrotic tissue causing discomfort
how is fly strike treated?
topical - clip/clean area & manually remove maggots
systemic - antibiotics if febrile, appears septic, & possibly ivermectin
how is fly strike prevented in sheep?
shearing around the head, perineum, & ventrum of males
what is the fancy name for sheep keds?
melophagus ovinus - wingless flies
what is the life cycle of melophagus ovinus?
3 week life cycle on host with adults as blood suckers
what are the clinical signs of sheep keds?
pruritus, stained wool, skin nodules, anemia, & weight loss
what is this?
wingless flies!! sheep keds!!
what is the treatment for sheep keds?
LOTS OF THEM!!
prevent!!!
treat animals topically after shearing
where is hypodermiasis common?
in cattle in the northern hemisphere worldwide
why does hypodermiasis cause economic losses?
hide damage, weight loss, cause stampedes, ‘gadding’, ‘fly worry’, & animals will stand in water and not eat
what are the 2 species of hypoderma?
hypoderma bovis
hypoderma lineatum
what is the life cycle/pathogenesis of hypodermiasis?
eggs are laid on legs (h. lineatum) or rump (l. bovis) & hatch in 3-7 days
penetrate the skin & migrate in SQ layers
in late fall/early winter - h. lineatum to esophagus & h. bovis to spinal canal
L1 remains there 2-4 months
jan/feb larvae go to SC tissues of back & cut a breathing hole through the skin, molt from L1-L3 over 4-6 weeks
L3 falls off & pupates to adult in 1-3 months
what are the clinical signs of hypodermiasis?
SQ nodules, posterior paralysis, bloat, & anaphylaxis
how is hypodermiasis diagnosed?
presence of nodules on the animal
what is the treatment for warbles in hypodermiasis?
physical removal
what is the treatment for larvae in hypodermiasis?
organophosphates, macrocyclic lactones
avoid treatment during the 2-3 months before the expected appearance of grubs along the back (not treatment from october 1st-march 1st)
what animals are affected by stephanophilariasis? what is the agent?
cattle - stephanophilaria stilesi
how is stephanophilariasis transmitted?
horn flies
what are the clinical signs of stephanophilariasis?
papules, crusts, ulcers, & hyperkeratosis
how is stephanophilariasis diagnosed?
by appearance & location of lesions
what is the treatment for stephanophilariasis?
there is none
what disease is this lesion associated with?
stephanophilariasis
what is hanging out in this tissue biopsy?
scabies!!
what is a dermatophyte?
unique fungi that invades & lives in keratinized tissue
what 3 genera of dermatophytes are common in food animals?
microsporum
trichophyton
epidermophyton
what animals are affected by trichophyton verrucosum?
cattle & goats
what animals are affected by trichophyton mentagrophytes?
cattle & goats
what animals are affected by microsporum nanum?
pigs & llamas
what is this?
microsporum dermatophyte
what is this?
trichophyton dermatophyte
what is this?
epidermophyton dermatophyte
why does dermatophytosis cause alopecia?
dermatophytes invade keratinized structures (hair, stratum corneum, horns, claws), & with the invasion of the hair shaft, it becomes weakened & breaks off
why does transmission of dermatophytosis vary?
amount & period of exposure
immuno-competency of the animal
& IT IS ZOONOTIC
what are the clinical signs of dermatophytosis?
alopecia (centrifugal pattern, the ring), crusts, erythema, papules, +/- pruritus (typically not pruritic), & claws/hooves weaken & split
how is dermatophytosis diagnosed?
90% - fungal culture
microscopic examination of hair/crusts with a KOH prep, but difficult to do
biopsy - quick & use special stains, dx 70% of the time
what is the treatment for large areas of dermatophytosis?
lime sulfur 5% 2x/week
bleach 1:10 solution but not in black show animals
chlorhexidine
what is the treatment for small areas of dermatophytosis?
shampoos or rinses with miconazole or ketaconazole plus chlorhexidine
what species are affected by papillomatosis? what is the causative agent?
cattle
papillomavirus
what animals are more so affected by papillomatosis?
confined & young animals
how is papillomatosis transmitted?
direct contact & fomites
what clinical signs are associated with papillomatosis BPV-1?
teats & penis affected
what clinical signs are associated with papillomatosis BPV-2?
head & neck affected
what clinical signs are associated with papillomatosis BPV-3?
atypical - body affected
what clinical signs are associated with papillomatosis BPV-4?
gi affected
what clinical signs are associated with papillomatosis BPV-5?
rice grain
what clinical signs are associated with papillomatosis BPV-6?
teat & udder affected
how is papillomatosis diagnosed?
appearance & skin biopsy
what is this lesion of?
papillomatosis
what is the treatment for papillomatosis?
spontaneous regression
surgical resection, cryotherapy, hyperthermia, & vaccine
what species are affected by dermatophilosis?
cattle, sheep, goats, & llamas
what is the causative agent of dermatophilosis?
dermatophilus congolensis
what animals are predisposed to getting dermatophilosis?
animals with skin damage, wet environments, & carrier animals
how is dermatophilosis transmitted?
direct contact & fomites
this lesion is consistent with what disease?
dermatophilosis
what are the clinical signs of dermatophilosis?
papules, pustules, & purulent exudate under thick scabs
how is dermatophilosis diagnosed/
direct smear, minced crust smear, & culture
what is the treatment for dermatophilosis?
remove crusts & dry out lesions
penicillin
oxytetracycline
what is the causative agent in this picture?
dermatophilus congolensis
what is the causative agent of caseous lymphadenitis?
corynebacterium pseudotuberculosis
what species are affected by caseous lymphadenitis?
sheep & goats
how is caseous lymphadenitis transmitted?
direct contact, inhalation, & ingestion
what does this animal have?
caseous lymphadenitis
why am I worried about caseous lymphadenitis in the long term?
can cause long term biosecurity problems in the herd if there are SQ abscesses
what are the clinical signs of caseous lymphadenitis?
lymph node abscesses, internal abscesses causing organ dysfunction in the liver, lungs, & kidneys, & weight loss
if you have sheep/goat presenting with chronic weight loss, what should be on your differential list?
caseous lymphadenitis
how is caseous lymphadenitis diagnosed?
appearance, culture, & serology (SHI test)
how is caseous lymphadenitis treated?
benign neglect
lance/drain/flush
surgical removal
how is caseous lymphadenitis prevented?
vaccination
what species are affected by contagious ecthyma?
sheep, goats, & llamas
what is the causative agent of contagious ecthyma?
parapoxvirus
what is the epidemiology of contagious ecthyma?
endemic on farms & periodic outbreaks
how is contagious ecthyma transmitted?
direct contact & scabs in the environment
what are the clinical signs of contagious ecthyma?
papules, vesicles, crusts, scabs, pain, & anorexia
what is your differential?
contagious ecthyma
how is contagious ecthyma diagnosed?
clinical signs & biopsy
how is contagious ecthyma treated?
spontaneous resolution & supportive care
how is contagious ecthyma prevented?
vaccination
can a human get contagious ecthyma?
yup
what species are affected by photosensitization?
cattle, sheep, goat, llamas
what is causative agents of photosensitization?
photodynamic agents in the skin
hepatic disease/failure
what is the mechanism of primary photosensitization?
plant/chemical contains a photodynamic agent or metabolite
what is the mechanism of secondary photosensitization?
liver disease leads to accumulation of phylloerythrin in skin - phylloerythrnis are a breakdown product of chlorophyll
what is the mechanism of porphyria photosensitization?
abnormal heme synthesis, poryphrin accumulation, & genetic
what plants cause primary photosensitization?
st. john’s wort - hypericin
buckwheat - fagopyrin
perrennial ryegrass - perloline
cocoa shells
what chemicals cause primary photosensitization?
phenothiazines, thiazides, methylene blue, tetracyclines, & sulfonamides
how is photosensitization treated?
decrease exposure to sunlight
remove exposure to photodynamic agent or liver toxin
supportive care for treating liver disease - keep the animal eating & use antibiotics if needed
what species if affected by erysipelas?
swine
what is the causative agent of erysipelas?
erysipelothrix rhusiopathiae
what is another name for erysipelas?
diamond skin disease
how is erysipelas transmitted?
through infected animals & environmental contamination
what are the acute clinical signs of erysipelas?
sudden death, fever, walking stiffly on toes, anorexia, thirst, red to purple widespread discoloration on the ears, snout, & abdomen, & diamond shaped skin lesions
what’s your differential?
erysipelas
what are the subacute clinical signs of erysipelas?
diamond shaped skin lesions, anorexia, & fever
what are the chronic clinical signs of erysipelas?
arthritis & valvular endocarditis
how is erysipelas diagnosed?
skin lesions are pathognomonic
isolation of organism from tissues
what is the treatment for acute erysipelas?
penicillin - rapid response
what is the chronic treatment for erysipelas?
difficult in production pigs & pets
how is erysipelas prevented?
vaccination - 3 to 4 weeks before farrowing & every 6 months
why is it concerning that erysipelas is zoonotic?
can lead to endocarditis & septicemia
what is the scientific name for greasy pig disease?
exudative epidermitis
what species are affected by exudative epidermitis?
swinde - few days to 8 weeks
what is the causative agent of exudative epidermitis?
staphylococcus hyicus
what is the epidemiology of exudative epidermitis?
unclear! presence doesn’t indicate disease
may be pustular dermatitis & suppurative folliculitis
what are the clinical signs associated with exudative epidermitis?
listlessness, anorexia, reddened skin, brown exudative spots, may become generalized over 24-48 hours, & may be fatal
what’s your differential?
exudative epidermitis
how is exudative epidermitis diagnosed?
clinical signs, culture, & histopathology
what is the treatment for exudative epidermitis?
unrewarding - antimicrobials & chlorhexidine baths
how is exudative epidermitis prevented?
sanitation & good hygiene
what species are affected by zinc responsive dermatosis?
camelids, goats, cattle, & sheep
what are the causative agents of zinc responsive dermatosis? what is the epidemiology?
low zinc diets
antagonist diets
hereditary problems
may affect one or many animals
what are the clinical signs of zinc responsive dermatosis?
dull haircoat, scaling, alopecia, & hyperkeratosis
how is zinc responsive dermatosis diagnosed?
plasma zn - royal blue top tube
response to therapy - poor option
what is the treatment for zinc responsive dermatosis?
zinc supplementation - be wary of declining copper
