Exam 2 - Pruritus Flashcards

1
Q

what are the big 3 categories of disease that should be considered for a pruritic animal?

A

parasites, microbial, & allergies

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2
Q

‘what are the infections? why are they there?’

what are examples of each category when approaching a case of a pruritic animal

A

infections - folliculitis, yeast dermatitis, ectoparasitism

why are they there - allergy (young to middle-aged animals), endocrinopathy (middle aged to senior), cornification (young or specific breeds), anatomical

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3
Q

when confronted with a pruritic patient, what should you rule out first?

A

parasites & skin infections

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4
Q

what is the pathway of pruritus?

A

stimulus activates a mediator -> pruriceptor of afferent neuron -> peripheral pathway through the dorsal root ganglion -> central processing & modulation -> interpretation & perception -> response to itch

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5
Q

what are some examples of pruritogenic substances?

A

histamine, proteases, lipases, eicosanoids, kinins, opioids, substance P, exogenous factors from bacteria/fungi/pathogens

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6
Q

what is epicritic itch? what is the transmission of it through the body?

A

well-delineated, sharp, spontaneous itch

transmission - myelinated fast-conducting A axons

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7
Q

what is protopathic itch? what is the transmission of it through the body?

A

poorly-delineated, burning itch

transmission - polymodal nociceptor units with unmyelinated slow-conducting C axons

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8
Q

what is the gate control theory in regards to pruritus?

A

higher CNS factors may accentuate or lessen the pruritic sensation

anxiety, stress, boredom, playing, & other learned experiences influence the sensation of pruritus

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9
Q

why is mast cell concentration an important factor to consider in a pruritic patient?

A

mast cells have a higher dermal concentration in the pinnal & ventral interdigital pedal skin compared to other parts of the body - common itchy areas for animals with allergic skin disease

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10
Q

T/F: petting a cat against the direction of hair growth may reveal barbered hair which is highly suggestive of a self-induced injury from pruritus

A

true

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11
Q

what are some examples of feline cutaneous reaction patterns?

A

miliary dermatitis, self-induced alopecia, cervicofacial pruritic dermatitis, & eosinophilic granuloma complex

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12
Q

what is a feline cutaneous reaction pattern?

A

reaction patterns that aren’t diagnoses but rather lesional clues of an underlying pruritic and/or allergic disorder

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13
Q

what is the pruritic threshold?

A

level of pruritus required to elicit the sensation of pruritus - this level is different for each individual animal

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14
Q

what is the summation effect?

A

additional stimuli exacerbate & compound the sensation of prurirtus

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15
Q

what immediate side effects are seen with animals on glucocorticoids?

A

PU/PD/PP & panting

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16
Q

what are some cutaneous side effects associated with animals on glucocorticoids?

A

alopecia, hair color/texture changes, comedones, scaling, seborrhea, hyperpigmentation, thin atrophic skin, inelastic skin, poor wound healing

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17
Q

what are some musculoskeletal side effects associated with animals on glucocorticoids?

A

muscle atrophy & weakness (including intercostals & abdominal muscles -> panting & pot belly) & ruptured cruciate ligaments

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18
Q

what is the goal of using glucocorticoids when treating a pruritic animal?

A

make the animal comfortable with a humane level of itch but not to make them 100% itch-free since the risks of glucocorticoid use begins to trump the benefits of use

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19
Q

T/F: if your patient requires longer than 3-4 months of oral glucocorticoids to manage allergic skin disease, other treatment options should be sought out

A

true

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20
Q

what drug is FDA labeled for treating canine atopic dermatitis?

A

atopica - cyclosporine

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21
Q

what drug is FDA labeled for treating feline allergic dermatitis?

A

atopica for cats - cyclosporine

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22
Q

what drug has an FDA label for canine pruritus associated with allergic skin disease & canine atopic dermatitis?

A

oclacitnib - apoquel

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23
Q

what is lokivetmab?

A

cytopoint - caninized (dog-specific antibody) anti-cIL-31 monoclonal antibody (mAb) for canine allergic dermatitis & atopic dermatitis

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24
Q

what is the goal of allergen-specific immunotherapy (ASIT)?

A

reduce the intensity & severity of clinical signs along with reducing the frequency of/possible need for other therapies best avoided long-term such as glucocorticoids/cyclosporine

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25
Q

how does ASIT work?

A

ASIT retrains the immune system on how to perceive its environment

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26
Q

what animals is ASIT mainly reserved for?

A

atopic animals who are affected at least 6 months out of the year who do not tolerate symptomatic therapy or can’t receive symptomatic therapy

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27
Q

for canine atopic dermatitis affecting animals less than 6 months of the year, what are your absolutes you must use for treatments? what are your options?

A

absolutes - adulticidal flea prevention, infection control, & baths

options - cytopoint, oclacitnib, & glucocorticoids

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28
Q

for canine atopic dermatitis affecting animals more than 6 months of the year, what are your absolutes you must use for treatments? what are your options for animals less than 7-8 years old? what about older than 7-8 years old?

A

absolutes - adulticidal flea prevention, infection control, & baths

options for 7-8 y/o - cytopoint & ASIT

options for > 7-8 y/o - cytopoint, apoquel, atopica, +/- ASIT

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29
Q

when managing a patient with atopic dermatitis, what therapies can be used for pruritic flares?

A

apoquel or glucocorticoids - topical or systemic

cytopoint - given less frequently than every 4 weeks when receiving other atopic meds

30
Q

what 3 drugs are you not going to use in a patient with pruritic skin disease from demodicosis?

A

apoqel, glucocorticoids, & cyclosporine

31
Q

what skin condition is associated with this pruritic pattern/distribution? how will you work this patient up?

A

folliculitis - happening on haired skin - asymmetric/patchy superficial lesions

history/pattern of itch/lesions, cytology, deep skin scrapes, & DTM/PCR - need to rule out superficial pyoderma, dermatophytosis, & demodicosis

32
Q

what skin condition is associated with this pruritic pattern/distribution? how will you work this patient up?

A

yeast dermatitis (malassezia) - lesions in body folds, seborrhea, erythema, scaling, hyperpigmentation, lichenification, alopecia

history, pattern of itch/lesions, & cytology

33
Q

what do you think is happening here?

A

yeast dermatitis

34
Q

what requirements must be met before prescribing apoquel for your patient?

A

demodex has been excluded & the patient is older than 1 year

35
Q

____% of all dogs develop signs of food allergies by 1 year of age

A

40%

36
Q

a positive pinnal-pedal response is fairly specific for what skin condition?

A

scabies

37
Q

what is the pinnal-pedal reflex in dogs?

A

rubbing of the pinna/ear flap causes the ipsilateral hind leg to start a scratching motion

38
Q

what skin condition is associated with this pruritic pattern/distribution? how will you work this patient up?

A

flea allergy dermatitis - lesions on caudal body, excoriation, erythema, self-induced alopecia, scaling, crusted papules, & hot spots

history, pattern of itch & lesions, +/- fleas with a flea comb, look for flea dirt, look for tapeworms, & evaluate response to therapy

39
Q

what skin condition is associated with this pruritic pattern/distribution? how will you work this patient up?

A

sarcoptic mange - lesions seen in sparsely haired areas, severely pruritic, excoriations, erythema, self-induced alopecia, crusted papules, & scaling

history, pattern of itch/lesions, + pinnal-pedal response, do superficial skin scrapes, ELISA test, & monitor response to therapy

40
Q

what is this? what does it cause?

A

sarcoptes scabei var. canis - sarcoptic mange

41
Q

what flea is most commonly implicated in causing flea allergy dermatitis?

A

ctenocephalides felis

42
Q

an outside dog that isn’t on any flea/tick prevention presents with this skin lesion - what do you suspect is going on?

A

flea allergy dermatitis

43
Q

a puppy that was recently adopted from a shelter presents severely pruritic, and upon doing a superficial skin scrape, you see this bug on cytology - what do you think is going on?

A

sarcoptic mange

44
Q

what dosing is used for oclacitnib for pruritic dogs?

A

0.4-0.6mg/kg by mouth every 12-24 hours

45
Q

how does oclacitnib work?

A

inhibits the production of pruritogenic & inflammatory signals induced by IL-2, IL-4, IL-6, IL-13 (allergy & inflammation), & IL-31 (pruritus) that are dependent upon JAK1 & JAK3 enzyme activity

46
Q

T/F: oclacitnib is an effective anti-pruritic that can be used during a flare up of itchiness & it can be used in a diagnostic work-up of a patient with allergic skin disease if needed

A

true

47
Q

what dosing is used for steroids for pruritic dogs?

A

prednisone at 0.5-1.0mg/kg by mouth every 24 hours for 7 days & then taper to lower dose every 48 hours over the next 5-10 days

48
Q

how do steroids work in stopping pruritus?

A

inhibit phospholipases of the cell membrane stopping the arachidonic acid cascade - stops inflammatory cytokines/signals/suppresses inflammatory response of the body

49
Q

T/F: at least 1 elimination diet trail should be performed when a pruritic patient has signs that are non-seasonal

A

true

50
Q

what are some clinical signs that may clue you in to a food allergy in a pruritic patient?

A

gi signs, pruritus, otitis, atopic dermatitis, & urticaria

51
Q

T/F: in dogs with atopic dermatitis, 30% of them will also experience adverse food reactions/allergies

A

true

52
Q

what is the difference between presenting signs of adverse food reactions in dogs & cats as far as lesion distribution & lesions go?

A

dogs - generalized pruritus, superficial pyoderma, otitis, hot spots, & atopic dermatitis

cats - cervicofacial pruritus, cutaneous reaction patterns

53
Q

what are some common food offenders for cats & dogs with adverse food reactions/allergies?

A

dogs - beef, dairy, chicken, wheat, & lamb

cats - beef, fish, & chicken

54
Q

how long should a diet trail last for a patient with adverse food reactions/allergies?

A

no more than 8 weeks

55
Q

after a patient has completed a diet trial of 8 weeks, what do you do next?

A

challenge them with previous foods to determine if signs reoccur within 2 weeks

56
Q

what are some examples of types of elimination diets/diet trials?

A

novel protein - venison, rabbit, kangaroo

hydrolyzed - chicken, soy, salmon

ultra-hydrolyzed - ultamino, EL

home prepared

57
Q

T/F: a multi-modal approach or regimen of therapy will provide the best results given the complexity/pathophysiology of pruritus

A

true

58
Q

why use essential fatty acids & ceramides when treating a pruritic patient?

A

omega 6 - improves epidermal barrier function & skin/coat luster

omega 3 - anti-inflammatory

ceramides - crucial in forming highly organized intercellular lipid lamellae in the stratum corneum, animals with atopic dermatitis has a deficiency of these which allows for allergen sensitization, infection, & dryness

59
Q

how do antihistamines work?

A

block H1 receptors & some antimuscarinic receptors (anticholinergic) effects, so antipruritic & lil sedation

60
Q

what animals have contraindications to antihistamines?

A

patients with a history of seizures, glaucoma, severe cardiac failure, urine retention, & ileus

61
Q

how do TCAs work for pruritic patients?

A

block H1 receptors, block norepinephrine & serotonin presynaptic receptors in the brain & some antimuscarinic receptors (anticholinergic) effects

62
Q

what are some side effects associated with TCAs?

A

tachycardia, arrhythmias, mydriasis, dry mouth, urine retention, constipation, & sedation

63
Q

what animals have contraindications to TCAs?

A

similar to antihistamines - along with cardiac problems & concurrent use of MAO inhibitors, SSRIs, & other TCAs

64
Q

when may TCAs be useful in pruritic cats?

A

in pruritic cats with self-induced alopecia when trying to figure out how much of the condition is related to a primary/secondary dermatological or behavioral disorder

65
Q

what is canine atopic dermatitis?

A

genetically predisposed inflammatory & pruritic allergic skin disease with characteristic clinical features associated with IgE Ab most commonly directed against environmental allergens

66
Q

how do calcineurin inhibitors, such as cyclosporine & tacrolimus, work for treating pruritus?

A

drug binds to t-lymphocyte cytoplasmic ligand & inhibits calcineurin (calcium-activated protein phosphatase) -> leads to dephosphorylation of cytoplasmic subunit of NFAT inhibited -> phosphorylated NFAT can’t translocate to the nucleus -> so the transcription of various cytokines is prohibited (IL-2, IL-4, TNF-alpha)

67
Q

what side effects are associated with calcineurin inhibitors? any contraindications when using this drug?

A

inappetence, vomiting, diarrhea, increased hair shedding, hypertrichosis, gingival hyperplasia, papilloma-like skin lesions

don’t give to an animal with known neoplasia & no modified-live vaccines should be administered when a patient is on this drug

68
Q

what contraindications do pruritic feline patients have in regards to cyclosporine?

A

don’t give to patients with FIV/FeLV, FIP, or known neoplasia

69
Q

what precautions should be taken when prescribing cyclosporine to a cat?

A

needs to have a negative toxoplasma titer, look for any renal insufficiency, & diabetes mellitus - must avoid situations for toxoplasma exposure so no hunting/raw diets - need to keep cat inside)

70
Q

what dosing is used for lokivetmab?

A

SQ injection every 4-8 weeks as needed at a minimum dose of 2mg/kg according to supplied dosing table

71
Q

T/F: ASIT is a cure for atopic dermatitis

A

false

72
Q

what drug is the mainstay therapy for treating demodicosis, scabies, & most ectoparasites?

A

isoxazolines - simparica, nexguard, bravecto, credelio