Exam 1 - Equine Pruritus Flashcards
1
Q
what is erythema/erythroderma? what does it typically indicate?
A
redness - inflammatory process
2
Q
what is this lesion? primary or secondary?
A
macule/patch - primary
3
Q
what is this lesion? primary or secondary?
A
papules - primary
typically less than 1 cm, represents cell infiltration
4
Q
what is this lesion? primary or secondary? would you sample this?
A
pustule - primary, yes
5
Q
what is this lesion type? what animal is it common in?
A
plaque - coalescing papules that you can palpate change in elevation
cats
6
Q
what is the difference between a vesicle & bulla?
A
vesicle is a smaller version of a bulla
7
Q
what is this lesion? primary or secondary?
A
vesicle/bulla - primary
8
Q
what diagnostic test would you use for this primary lesion?
A
biopsy/culture
this is a nodule - has a large infiltration of cells that can be infectious, inflammatory, or neoplastic in nature
9
Q
what is this primary lesion type? what animals commonly get these?
A
wheal/urticaria (hives) - horses
10
Q
what is this lesion? primary or secondary?
A
epidermal collarette - secondary lesion
11
Q
why are epidermal collarettes secondary lesions?
A
it is a ruptured pustule!!
12
Q
what is this? how does it occur
A
erosion/ulcer
a vesicle/bulla ruptures - determined to be an erosion or ulcer by the depth of the lesion
13
Q
what is the difference between an erosion & an ulcer?
A
an erosion is more superficial, is only epidermis, & heals without a scar
an ulcer crosses into the dermis & heals with a scar
14
Q
what is this? what does its presence imply?
A
lichenification - implies chronicity & is commonly seen with hyperpigmentation
15
Q
what is this lesion & how is it caused?
A
excoriation - self-induced version of an erosion/ulcer, typically seen in a linear fashion
16
Q
what is this lesion? why can it be either primary or secondary?
A
scale
primary - animal has an inability to make normal skin
secondary - secondary to infection
17
Q
what is this lesion? why can it be either a primary or secondary lesion?
A
crust
primary - autoimmune disease
secondary - ruptured pustule (scab)
18
Q
what is this lesion?
A
crust
19
Q
follicular casts can be primary or secondary & are commonly seen with what infection?
A
dermatophytosis
20
Q
what is this?
A
follicular casts - paint brush appearance
21
Q
what is this lesion? primary or secondary?
A
comedones - blackhead, plugged follicle that is oxidized
can be either primary or secondary
22
Q
what is this lesion?
A
hyperpigmentation - primary (birthmark)
23
Q
what is the difference in primary & secondary hyperpigmentation?
A
primary would be something like a birthmark or freckle
secondary - longterm problem, allergies/infection, can go away in time
24
Q
how can hypopigmentation/depigmentation be a primary or secondary lesion?
A
primary - vitiligo (autoimmune)
secondary - disruption of the lower layers of the epidermis
25
why is it important to differentiate inflammatory alopecia from non-inflammatory alopecia?
inflammatory - hair is being pulled/scratched out
non-inflammatory - hair is falling out
helpful to indicate pruritic disease
26
what are the first 4 steps when approaching dermatological lesions in horses?
1. what am I looking at?
2. is it a primary or secondary lesion?
3. what is the pattern?
4. why is it here? need a sound history (pruritic or not)
27
what are some clinical signs of itching in horses that an owner may not notice?
tail twitching, stomping, rolling, & head shaking
28
what big 3 categories are you approaching dermatology cases with?
parasites, infections, & allergies
29
what is xeroderma?
dry skin
30
big 3 components for working up a pruritic horse?
history
clinical signs
physical examination
31
why is location so important when looking at dermatological lesions?
helps narrow down your differentials
32
what is your minimum database when starting a derm case?
parasite combing, skin scrape, anti-parasite trials/fly control, & skin cytology
33
if your minimum database doesn't provide many results, what may you pursue diagnostically?
allergy trials
culture
biopsy
34
what are the two main categories that cause pruritic disease?
parasites & infection
35
when might you use a skin scrape?
suspect mites - get multiple sites including the feathers
36
if doing an impression cytology, what do you want to sample?
intact pustule or underneath a crust
37
what is the most common fungal infection seen in horses?
trichophyton
38
if doing a fungal culture in horses, what must you do for monitoring & what is required for growth?
monitor daily & keep for 21 days
needs B vitamins
39
what is pediculosis?
lice!!!!
40
what kind of lice is this?
biting - werneckiella equi
41
what kind of lice is this?
sucking - haematopinus asini
42
if I am concerned about my horse having biting lice, where should I look?
head, mane, & tail base - they loooove exfoliated skin cells & debris
43
if i'm scared my horse has sucking lice, where do I look?
head, neck, back, thighs, & fetlocks - they looove blood & tissue fluid
44
why is it good and bad that lice are species/host specific?
good because I can't get them
bad because their horse/donkey friends will definitely get them because it is contagious
45
what season am I worried most about lice?
colder months
46
what animals do lice prefer?
young, old, & debilitated animals in over-crowded settings
47
what clinical signs may I see if my horse has lice?
variable pruritus, scaling, poor hair coat, alopecia, & anemia (rare)
48
why is this scary!
it's LICE
49
why would you scream if you saw this?
it's lice and there is no other reason needed
50
when considering ticks as the source of pruritus in a horse, this will be more of a _______ problem (focal/multifocal/diffuse)
focal
51
with most ticks being 3 host ticks, why does this make our lives more difficult?
parasite control becomes harder
52
this silly hat will help protect my horse from what tick?
otobius megnini - causes otitis externa
53
what clinical signs are commonly seen with otobius megnini?
head shaking, head rubbing, abnormal head carriage, seizures (rare), & ataxia (rare)
54
I have a bunch of itchy horses with distribution seen in the red....why am I concerned?
psoroptes equi!!!! a non-burrowing mite!!!!!!
55
how is psoroptes equi spread?
direct or indirect contact
56
T/F: ears are usually affected as well in psoroptes equi infections
true
57
why should you treat all in-contact animals with psoroptes equi?
10% of your herd????
58
if my horse is itchy in these locations......why am I scared?
SARCOPTES SCABEI!!!!!
59
can I get sarcoptes scabei?
yup! zoonotic!
60
what do I do immediately if my horse has sarcoptes scabei???
REPORT IT!!!! it's eradicated in the USA
61
clinical signs of sarcoptes scabei?
INTENSE PRURITUS!!! severe disease :/
62
what kind of mite is sarcoptes scabei? (burrowing/non-burrowing)
burrowing
63
if this is where my horse is itchy, what am I thinking??
chorioptes equi!!! in my feathered draft breeds!
64
how is chorioptes equi spread?
direct or indirect contact - animals may be asymptomatic carriers
65
what season is chorioptes equi common in?
winter time
66
top differential?
chorioptes equi
67
what are the 3 mites you're looking for when doing a skin scrape?
psoroptes, sarcoptes, & chorioptes
68
name that mite!
sarcoptes scabei
69
name that mite!
chorioptes!
70
name that mite!
psoroptes
71
what is the fancy name for chiggers?
trombiculiasis
72
'papules with an orange dot in the center' - describes what?
chiggers
dot = chigger larva
73
what seasons are chiggers more prevalent? what environments?
summer & fall
pasture, paddocks, & trails (tall grass)
74
why do chiggers cause itching?
the larvae feed on tissue fluid
75
this distribution is common for what small bug?
chiggers
76
between our 2 nematode parasites, which one causes pruritic signs & which one causes nodular lesions? (oncocerca cervicalis & habronema)
pruritus - oncocerca cervicalis
nodular lesions - habronema sp.
77
what is the pathogenesis of oncocerca cervicalis?
the wormies live in the nuchal ligament & produce microfilaria that migrate to the skin & are ingested by the intermediate host culicoides (biting midges)
this leads to non-seasonal pruritus that is highest in populations in the spring - causing idiosyncratic hypersensitivity reactions to microfilarial antigens
78
this lesion distribution is common in what nematode infestation
oncocerca cervicalis - cutaneous lesions associated with microfilaria deposition
79
with the prevalence of infection being high with oncocerca cervicalis, how should I treat this?
use ivermectin & moxidectin dewormers
80
T/F: only some horses will develop clinical signs with oncocerca cervicalis infestations & horses older than 4 years old are more likely to be having issues
true
81
what ocular lesions may be seen in oncocerca cervicalis infections?
sclerosing keratitis
vitiligo (bulbar conjunctiva)
white nodules (pigmented conjunctiva)
uveitis
depigmentation bordering the optic disk
82
what is a permanent change seen in oncocerca cervicalis infections?
leukoderma at the site of skin lesions
83
what is the fancy science name for pinworms??
oxyuris equi
84
this lesion distribution is commonly seen with what parasitic infection?
oxyuris equi - itchy ass!!!
85
how do horses get pinworms?
the ingest the eggs from their environment
86
what are the clinical signs seen with pinworms? what horses does it typically affect?
restlessness, irritability, itchy ass
stabled horses
87
if I suspect pinworms, what diagnostic test should I do? what would I expect to see?
tape prep!!
eggs on the tape prep of the perineum
88
what is this?
pin worms - oxyuris equi
89
T/F: differential diagnoses for pruritus in the horse regarding infections is generally secondary to something else
true
90
what are my big three differentials for pruritic infections in the horse?
bacteria, dermatophytosis, & malassezia
91
if I see an itchy horse with this lesion distribution, what am I thinking?
bacterial follicultis - staph spp. (s. aureus, delphini, pseudintermedius)
92
T/F: bacterial folliculitis is common & is often mistaken for dermatophytosis
true
93
if I suspect bacterial folliculitis, what is my first line of treatment?
TOPICALS!!!!!!!!! antiseptic therapy!!!!! this is a superficial bacterial problem
94
why is topical therapy important to use for bacterial folliculitis?
decreases organism adherence & numbers, mechanical removal of infectious debris, decreases the need for antibiotics, additional beneficial properties such as drying/soothing, & there is a greater chance for resistance to antibiotics than an antiseptic
95
what is the most common MRSA in dogs? horses? which one is a bigger concern?
dogs - s. pseudintermedius
horses - s. aureus
s. aureus - this is a people problem!!
96
T/F: malassezia dermatitis is historically under-reported in horses
true
97
what body areas are commonly affected in horses with malassezia problems?
skin folds!! causes a greasy-waxy exudate
98
what is this?
malassezia
99
what is the most common cause of equine pruritus??
insect hypersensitivity!!
100
T/F: insect hypersensitivity is usually a type 1 hypersensitivity that is mediated by IgE & may progress to a type IV hypersensitivity
true
101
what are the 3 bugs i'm thinking about when it comes to insect hypersensitivity?
flies, mosquitoes, & culicoides
102
why does it matter that I know what bug is affecting my horse?
controlling the insects causing the problem will control my insect hypersensitivity problem!
103
how do I know what insect is causing my horse problems??
-feeding location preferences
- time of day for feeding
-environmental requirements
104
what is the lesion distribution for gnats (culicoides)?
dorsum, ventrum, face, & ears
105
what bug causes this lesion distribution??
culicoides!
106
what bug is the most common cause of insect hypersensitivity?
culicoides!!
107
what is the feeding time for culicoides?
twilight to dawn
108
what environment is needed for culicoides?
STANDING WATER, manure, & vegetation
109
T/F: big fans in stables can help with a culicoides problem because they are weak fliers
true
110
what are common names for culicoides problems?
queensland itch & sweet itch
111
what is the lesion distribution for mosquitoes?
ventral midline, lower limbs, & may be generalized
112
what bug causes this lesion distribution?
mosquitoes
113
what is the feeding time for mosquitoes?
feed dusk to 2 hours past sunset
114
what is the environment for mosquitoes?
water
115
what bug causes this lesion localization?
horse flies - tabanus
116
what is the lesion distribution for horse flies?
ventral midline, neck, ears, lower limbs, & generalized all over because they are mean
117
what time of day do horse flies feed?
daytime
118
what is the environment for horse flies?
vegetation & water
119
like the horse flies, this fly also has a lesion distribution of ventral midline, neck, ears, lower limbs, & generalized all over. what is it?
deer fly - chrysops
120
what is the feeding time for deer flies? environment?
daytime
vegetation & water
121
what fly is generally associated with the presence of cattle? why?
horn flies - haematobia
they loooove poop in their environment
122
what fly causes this lesion distribution?
horn flies
123
what is the lesion distribution for horn flies?
ventral midline
124
what time of day do horn flies feed?
daytime
125
what fly has an environment of rotting vegetation?
stable flies - stomoxys
126
what time of day do stable flies feed?
daytime
127
what is the lesion distribution of stable flies?
dorsum, ventrum, midline, neck, & lower limbs
128
what fly causes this lesion distribution?
stable flies
129
what fly causes this lesion distribution?`
black flies - simulium
130
what is the lesion distribution of black flies?
face (especially ventral chin), ears, & ventral midline
131
what is the feeding time for black flies?
morning & evening feeders
132
what environment is needed for black flies?
RUNNING water
133
how can I improve my management of insect control in regards to my horse's environment?
clean it up!!
remove decaying vegetation, manure, & standing water
134
how can I improve my management of insect control in regards to my changing my horse's environment?
use fans in stalls, mesh guards, move them away from cattle, & move from pasture to stable in consideration of feeding times
135
how can I improve my management of insect control in regards to my horse's environment when considering time in the pasture?
stall the horses during peak feeding times
136
T/F: permethrin & oil products last longer than pyrethrins for insect control
true
137
what should be my first line of treatment for insect control?
topical insecticides, fly mesh, & fly sheets
138
what is atopic dermatitis?
genetically predisposed inflammatory & pruritic allergic skin disease with characteristic clinical features associated with IgE antibodies most commonly directed against environmental allergens - allergic to something in the environment
139
why should 'buyer beware' in cases of atopic dermatitis?
horse may have been sold in their good season when they are not clinical
can be seasonal or non-seasonal
140
how does an animal get atopic dermatitis?
inherited predisposition to form sensitizing antibodies to environmental allergens such as pollens, molds, dust, & storage mites
141
what are some examples of pro-inflammatory mediators in atopic dermatitis?
histamine, heparin, leukotrienes, prostaglandins, bradykinin, chymase, tryptase, & platelet activating factors
142
what is the lesion distribution of atopic dermatitis?
bilaterally symmetrical!! pruritus may or may not be generalized/seasonal
143
what clinical sign is commonly seen with atopic dermatitis?
urticaria
144
how is atopic dermatitis diagnosed?
clinical diagnosis is based on exclusion of other pruritic skin diseases - there is no specific test
but - positive serum/skin testing can support your diagnosis & guide therapy
145
what does treatment of atopic dermatitis with conservative medical management entail?
bathing, antihistamines, & fatty acid supplementation
146
what does treatment of atopic dermatitis with more aggressive medical management entail?
corticosteroids & apoquel - 0.25mg/kg
147
what does treatment of atopic dermatitis by retraining the immune system entail?
allergen specific immunotherapy
148
what are the downfalls of using steroids in horses?
possibility of developing laminitis, horses lack the ability of effective glucuronidation so use prednisolone instead of prednisone, & dexamethasone may have a lower probability of causing laminitis than other steroids
149
T/F: contact allergy in horses is rare
true
150
this lesion distribution in horses involves a type IV hypersensitivity & is rare in horses - what is it?
contact allergy
151
how do I avoid contact allergy in horses?
avoid the offending agents
152
what are the non-immunologic causes of urticaria?
cold-induced, exercise-induced, stress/psychogenic, sunlight, genetic, idiopathy, & dermatographism (pressure)
153
what are some examples of immunologic causes of urticaria?
allergic reaction, stinging insect, snake bite, infections, infestations, drug reactions (medication, vaccine, transfusion), plants, & vasculitis
154
what is the duration of chronic urticaria?
can last 6-8 weeks even though individual lesions are short lived - work up of the underlying cause/trigger is VERY important in these cases
155
T/F: with acute urticaria, empirical treatment with steroids/antihistamines can be used but you often won't find the underlying cause/trigger
true
156
each individual lesion of urticaria can last as long as _______ hours even without treatment
24-48 hours
157
what does your history work-up for urticaria include? what else should be looked at?
previous medications, change in temperature, change in exercise, vaccinations, & season
animal's environment
158
T/F: skin infections of horses are generally secondary to some other cause
true
159
what is an allergen?
antigen that favors the development of a hypersensitivity response
160
what is cellulitis?
diffuse inflammation of deep dermis & subcutaneous tissues
161
what is dermatophytosis?
fungal infection of keratinized skin, hair, or claws (ringworm)
162
what is furunculosis?
deep or penetrating folliculitis in which the integrity of the follicular wall has been compromised & follicular contents have escaped into the surrounding tissues
163
T/F: hyperpigmentation is often a result of chronic inflammation
true
164
what is leukoderma?
decreased pigmentation of the skin or non-pigmented skin
165
what is lichenification?
thickened/hardened skin with exaggerated epidermal markings seen in chronic skin disease
166
what is arguably the most important part of your dermatologic exam?
HISTORY
167
how do you diagnose lice?
combing - demonstrate nits/adult lice
168
what is the treatment for lice in warm weather? cold weather?
warm - bathing with insecticidal shampoo 3x a day for 10 days
colder weather/large number of animals affected - topical insecticides at labeled dose, typically 2 applications a day for 2 weeks
169
how do ticks causes problems in horses?
bite injury (secondary infection & myiasis), sucking blood, disease transmission, & tick paralysis
170
T/F: it is okay to use amitraz on horses with ticks
FALSE!!! don't
171
how are psoroptes mites diagnosed? treatment?
skin scrape may or may not help - response to treatment is often helpful
topical & oral antiparasitics
172
like psoroptes, how is sarcoptes diagnosed? treated?
skin scrape may or may not help - response to treatment is often helpful
topical & oral antiparasitics
173
feathered breeds & draft breeds are most commonly affected by what mites?
chorioptes
174
how is chorioptes diagnosed? treatment?
skin scrape, combing/brushing of feathers, demonstration of mites
clip feathers, thorough cleaning of barn/disinfection of tools/tack, & topical antiparasitics
175
what would a biopsy look like in a positive animal for oncocerca cervicalis?
superficial & deep perivascular to interstitial dermatitis with numerous eosinophils & microfilariae usually in superficial dermis
176
how do you diagnose malassezia? treatment?
cytology - yeast adhered to keratinocytes, waxy/greasy areas yield best samples
focal areas - daily cleaning & spot application of antifungals
multifocal/generalized lesions - total body application of shampoo and/or rinse twice weekly for 3 weeks
177
what is the hallmark of clinical signs with insect bite hypersensitivity?
pruritus
178
T/F: serum allergy testing and/or intradermal testing for insect bite hypersensitivity does not diagnose allergy
true
