Dermatology Flashcards
1
Q
what is a primary lesion?
A
the initial lesion is a direct reflection of the underlying disease, often appear and disappear quickly
2
Q
what are some examples of primary lesions?
A
macule, papule, nodule, vesicle/bulla, pustule, wheals
3
Q
what is a macule?
A
a flat spot, < 1 cm on skin with change in skin color
4
Q
what is a patch?
A
a macule > 1 cm
5
Q
what type of lesion is caused by underlying disease?
A
primary lesions
6
Q
what is a papule?
A
small, SOLID elevation in skin < 1 cm in diameter
7
Q
what is a pustule?
A
small elevation of epidermis filled with pus
8
Q
what is a vesicle?
A
elevation of epidermis filled with clear fluid
9
Q
what is a bulla?
A
a vesicle > 1 cm in diameter
10
Q
what is a wheal?
A
a sharply delineated lesion of edema
11
Q
what is a nodule?
A
solid raised palpable lesion > 1 cm
12
Q
what is a secondary lesion?
A
evolves from primary lesion or induced by patient or external factors, usually stay around for a longer period of time
13
Q
what are examples of secondary lesions?
A
epidermal collarette, lichenification, scar, excoriation, ulcer, fissure, callus
14
Q
which type of lesion lasts longer?
Primary vs. Secondary
A
Secondary
15
Q
what is an epidermal collarette associated with?
A
a pustule, vesicle or bulla
16
Q
what layer of skin does a scar effect?
A
the dermis or s/c tissue
17
Q
what is lichenification?
A
thickening or hardening of the skin
18
Q
what is an ulcer?
A
break in the epidermis with exposure of the dermis
19
Q
which lesions can be primary or secondary?
A
alopecia, scale, crust, follicular casts and comedone
20
Q
what is a follicular cast?
A
an accumulation of keratin and sebaceous material stuck to a hair shaft
21
Q
what is a comedone?
A
a dilated hair follicle filled with debris
22
Q
what are the derm screening tests?
A
scrapings, cytology and culture (dermatophyte and bacterial)
23
Q
what types of scrapes are there?
A
deep and superficial
24
Q
what do you look for on a superficial scrape?
A
surface mites like sarcoptes, notoedres, otodectes, cheyletiella demodex GATOI in cats
25
if scrape is negative, do you rule out mites?
no
26
what do we look for on a deep skin scrape?
follicular parasites like demodex spp.
27
what is the difference between deep and superficial skin scraping technique?
you squeeze the follicle and induce capillary hemorrhage with deep skin scrape
28
How do you perform a direct impression?
press slide onto lesion
29
what methods are used to perform a cytology and look for bacteria and yeast?
surface scrape, q-tip onto slide, tape test, impression, and a FNA
30
what is a trichogram for?
to look at hair
31
what can you see with a trichogram?
broken tips of hair, the root (anagen or telogen), ringworm, follicle dysplasia and surface parasites
32
what are some indications of bacterial culture and sensitivity?
- cytology shows cocci and rods or just rods
- deep pyoderma
- cocci but no response to right AB administered at the right dose at the right time
- chronic AB/GS therapy
- GSD pyoderma
33
what does a Wood's lamp detect?
ring worm - specifically M. canis strains since other ringworm strains won't fluoresce
34
what can cause false positives with the Wood's lamp?
keratin scale, soaps, dyes and medications can also flouresce
35
what are indications for fungal culture?
- ALL cats with skin disease!
| - dogs with inflammatory skin disease
36
what should you do if the hair shaft fluoresces?
pluck those hairs for the DTM inoculation to culture
37
how do you sample if nothing fluoresces?
use the sterile toothbrush technique by combing the pet with toothbrush to collect hair/scales to inoculate media
38
how often should you look at DTM culture?
EVERYDAY important for interpretation
39
what determines a positive DTM culture?
the media will turn red at the same time the dermatophyte colony appears
40
why do you have to observe the DTM culture everyday?
you need to know when the colony forms to check for color change because if left without watching non-pathogenic fungi can use the protein in the media and cause the same color change but that colony would be present for days before the color changes
41
should you prep and scrub for a skin biopsy?
no, can disturb lesion and become non-diagnostic
42
can you clip hair for a skin biopsy?
yes, you can gently clip the hair
43
what are some indications for skin biopsies?
- nodules/tumors
- ulcers/vesicles
- mucosal/footpad lesions
- lesions not responsive to normal therapy
- severe acute generalized disease
44
what do you do after you take a skin biopsy?
put it in 10% formalin
45
what are the types of biopsy techniques and when would you use them?
- wedge/excisional - for large or fragile lesions
- punch - for a sample of the disease process
- amputation - nail/toe
46
what is the gold standard for identifying environmental allergens ?
intradermal allergy testing
47
what does serological allergy testing rely on?
relies on antigen-specific antibody levels
48
what are some advantages/disadvantages of serological allergy testing?
advantages - quick, no sedation/clipping
disadvantages - no positive control, false positives/negatives, only detects circulating IgE, not reliable for food allergens
49
what will we see early on with pruritus?
alopecia, erythema, excoriations
50
what will we see with the chronic stage of pruritus?
lichenification, hyperpigmentation and seborrhea
51
what are the main categories of causes of pruritus in the dog?
allergies, ectoparasites and infections
52
what are allergic causes of pruritus in the dog?
- flea allergy
- atopic dermatitis
- cutaneous adverse food reaction
- insect bite hypersensitivity/contact dermatitis
53
what are ectoparasitic causes of pruritus in the dog?
- sarcoptes
- demodex
- cheyletiella
- lice
- chiggers
54
what types of infections cause pruritus in the dog?
- staph pyoderma
- yeast
- dermatophytes
55
how do you characterize pruritus?
the body sites, if there's seasonality, how intense, if the itch or skin lesion came first, age of onset
56
what could be a cause of pruritus on caudal dorsum?
flea allergy
57
what could be a cause of pruritus on elbows and ears?
sarcoptic mange
58
what could be a cause of feet licking and chewing?
atopy or food allergy
| "rears and ears" = food allergy
59
what causes of pruritus have seasonality to them?
- flea allergy
- atopy
- insect allergy
60
what causes the most severe pruritus (10 on the scale!)?
- sarcoptic mange (scabies)
- flea allergy
- food allergy
61
what should you consider if the pruritus came before the lesion?
allergies or scabies
62
what should you consider if the lesion came before the pruritus ?
demodex or dermatophytes
63
what should you look for during the PE for pruritus?
- look for lesions that confirm historical information
- look for pyoderma, lesion distribution, hair loss, etc.
- signs of immunosuppression that may predispose to infections
- CHECK EARS! often involved
64
what derm diagnostics should you do?
skin scrapings, surface cytology, flea comb, ear exam if needed
65
when should you recheck after starting a course of treatment for pruritus?
1-2 weeks, have a follow up plan if signs aren't improving
66
True or False.
| Flea allergy dermatitis (FAD) is very common
true, most common allergic skin condition in dogs and cats
67
what type of hypersensitivity is FAD?
type 1 hypersensitivity, antigen antibody reaction
68
True or False.
| An infestation is necessary for flea allergic dermatitis?
false, infestation is not necessary, you ca get an allergic response from only 1 bite
69
what is the main thing causing a reaction in FAD?
flea saliva because of the antigens it contains
70
what is the classical distribution of a lesion of FAD?
lumbo-sacral distribution and tail base
"pants" distribution
71
what signs will you see in a dog with FAD?
pruritus, papules, crust, excoriations, alopecia, hyperpigmentation and lichenification
may or may not see fleas or flea dirt
72
around what age does the onset of signs of FAD start?
between 1-3 years mostly but can be any age
73
what is a more definitive test for FAD?
intradermal flea allergy test - gold standard
- includes 3 injections - positive control, negative control
and flea antigen
there is also a serum test that measures flea allergen specific IgE
74
True or False.
| We consider all dermatoses flea related until proved otherwise
True. Even if a lesion is not classical - FAD is most likely involved
75
how do you treat FAD?
flea eradication
- ectoparasitic drugs on animal
- treat the environment
treat any secondary problems
76
true or false.
| a dog with FAD will always have FAD
True
77
are atopy and allergic dermatitis the same thing?
yes
78
what is atopy?
hypersensitivity type 1 to aeroallergens
79
what is the most common cause of primary otitis ?
atopy
| secondary infections are common with atopy
80
what other diseases can atopy occur concurrently with?
other allergic or pruritic diseases like FAD or food allergies
81
when should testing for atopy be done?
if a clinical diagnosis of atopy has been made or if allergen-specific immunotherapy is being considered
82
true or false.
| secondary infections are common with atopy.
True
83
what do the allergy tests detect ?
allergen specific IgE
84
do you see itching with atopy?
yes
85
what is the gold standard allergy test for atopy?
intradermal skin test
86
what kinds of allergy tests are available for atopy?
intradermal skin test and serum tests
87
prior to testing what should be done?
- avoid oral and topical steroids for at least 1 month before
- avoid antihistamines and essential fatty acids 2 weeks before
- no baths for 5 days before
88
what is the multimodal approach to treat atopy?
1. diagnose and control all infections
2. allergen avoidance
3. break the itch-scratch-itch cycle
4. allergen specific immunotherapy
89
what treatments show weak evidence of symptomatic relief with atopy?
- antihistamines
- essential fatty acids
- topicals
90
what treatments show fair evidence of symptomatic relief with atopy?
- skin lipid therapy
91
what treatments show strong evidence of symptomatic relief with atopy?
- glucocorticosteroids
- cyclosporine A (Atopica)
- oclacitinib (Apoquel)
- lokivetmab (Cytopoint)
- recombinant k9 interferon gamma (Interdog)
92
why is it important to treat atopy with skin lipid therapy?
the epidermal barrier is compromised and it leads to penetration by more allergens, irritants, yeasts and bacteria
skin lipid complexes restore the barrier
93
how do essential fatty acids help treat atopy?
they are an important part of the cell membrane phospholipid layer and form arachidonic acid which is less inflammatory
94
what is the goal when using corticosteroids for pruritus with atopic dogs?
to get to the lowest, most infrequent dose that will control the pruritus
95
how long should you minimally trial cyclosporine A for atopy?
4 weeks minimally
96
what are some potential problems with using apoquel?
- may increase susceptibility to infection and demodicosis
- may exacerbate neoplastic conditions
- avoid using in breeding dogs and pregnant or lactating ones
97
what are the signs of food allergies similar to?
signs are the same as allergic dermatitis, flea bite allergic dermatitis and scabies
all have non seasonal PRURITUS
98
if the onset of pruritus happens before 6 months of age what is likely the cause?
food allergies
99
true or false.
| food allergies are the second most common cause of hypersensitive skin disease
false, the third most common cause
order is: fleas, atopy then food allergies
100
will you see concurrent GI signs with food allergies?
yes, you can see vomiting, diarrhea and colic
101
how do you diagnose food allergies?
the only way to diagnose food allergy is a positive response to an elimination diet (food trial)
95% of dogs will improve within 3 weeks
102
how can we perform a food trial? (2 ways)
have the client feed a novel diet, either home cooked or commercial with a protein or carb thats never been consumed before or a hydrolyzed protein diet (like purina HA)
103
what type of hypersensitivity is contact hypersensitivity ?
type 4 hypersensitivity reaction - delayed/cell mediated reaction
104
what are the early lesions you see with contact hypersensitivity?
macules and/or papules
105
what can you see with chronic contact hypersensitivity?
lichenification, hyperkeratosis, hyperpigmentation, dryness, scaliness and fissuring
106
what is an example of something that could cause contact hypersensitivity?
an allergy to the bowl they eat out of or the collar they wear
107
how can we diagnose contact hypersensitivity?
we can try to do rule outs by:
- taking the dog out of its normal environment and seeing if it improves
- the patch test method, apply allergen directly to skin to see if there is a reaction
108
what is the treatment for contact hypersensitivity ?
- avoid allergen
- treat any present secondary infection
- topicals
- glucocorticoids
109
what is a very important clinical sign with sarcoptic mange?
INTENSE PRURITUS
110
what is important to tell owners about sarcoptic mange?
its zoonotic and very contagious to other animals
111
what are some clinical signs you see with sarcoptic mange?
intense pruritus, pinnal pedal reflex, papules, alopecia, erythema, crusts, excoriations, secondary weight loss, peripheral lymph node enlargement
112
what are the predilection sites for sarcoptes?
ears, elbows and ventral abdomen
where there are sparse amounts of hair
113
how can you diagnose sarcoptes?
- response to treatment
- positive pinnal-pedal reflex
- fecal float - can find mites (not always) if pet chews to itch and swallows mite
- skin scrape - however, extremely difficult to find the mite on scraping
114
how long do we treat sarcoptic mange?
minimum of 6 weeks
115
how do we treat sarcoptes?
- topical dips (lime sulfur or mitoban)
- topical spot on or systemic (selamectin, moxidectin, ivermectin, milbemycin or fipronil)
- clean all bedding/kennels
- treat secondary infections
116
if we choose to treat sarcoptic mange with a topical dip, what do we need to do? how often do we do them?
clip the hair, use an antiseborrheic shampoo prior to the dip then select which dip to use.
dip is done q 7 days x 6 weeks
117
why would you choose a lime sulfur dip over a amitraz (mitoban) dip?
lime sulfur dips are safe to use in young animals
118
how do we use topical spot ons for treatment of sarcpotic mange?
give every 2 weeks for about 2-3 weeks - we aim to treat for 6 weeks minimally
119
do we use glucocorticoids as an additional treatment for sarcoptes?
yes, you can use glucocorticoids in first few days of treatment to help with pruritus
120
what are some clinical signs you might see with cheyletiellosis?
walking dandruff, scaling, pruritus, papular crusts
121
how do we diagnose cheyletiellosis?
- acetate tape test for microscopy
- examine flea comb debris under microscope
- see with the naked eye crawling on fur
122
what is the treatment for cheyletiella?
- treat all in-contact animals and environment
| - topical shampoos and spot ons - can also use amitraz dips
123
how long do we treat for cheyletiella?
minimally 6 weeks
124
what are some clinical signs of chiggers?
- can be found around the legs, head and abdomen
- in cats, can be seen with naked eye, often found in ear
- look like paprika - red mites
- pruritis, papules, erythema
125
how can we diagnosis chiggers?
- skin scrapes
| - red color and clinical signs
126
how do we treat chiggers?
- two pyrethrin dips spaced two weeks apart
- topical anti-parasitic drugs
- prednisolone for a few days to help with itching
