MOD: Skin Diseases Flashcards
1
Q
What are adnexae?
A
Glands that supply hair follicles
2
Q
What are the 2 sub-types of spontaneous alopecia?
A
Inflammatory: inflammatory infiltrate damages hair follicle
Non-inflammatory: hair growth cycle disruption or abnormal formation of hair
3
Q
Are pruritic skin diseases usually inflammatory or non-inflammatory?
A
Inflammatory
4
Q
What are comedones?
A
Blackheads
5
Q
Give some examples of evidence of self-induced alopecia in cats
A
Short spiky hairs on physical exam
Vomiting hair balls
Hair in faeces
Clumps of hair in environment
Embedded hair in gingival sulci and tongue
Trichogram (look at hair under microscope-broken/frayed tips)
6
Q
What are the 3 main causes of inflammatory (spontaneous) alopecia?
A
Infectious agents
Parasites
Immune-mediated
7
Q
What are the 2 main causes of non-inflammatory (spontaneous) alopecia?
A
Hair follicle arrest
Hair synthesis defects
8
Q
What is the most common cause of bacterial folliculitis in dogs and cats?
Briefly describe it
A
Staphylococcus pseudointermedius (commensal flora)
Focal to multifocal patches of alopecia
+/- pustules, crusts
9
Q
What is the most common species of dermatophytosis (ringworm) affecting cats and dogs?
What type of animals does it typically affect?
A
Microsporum canis
Young/immuno-suppressed animals
Can have asymptomatic carriers
10
Q
How would you diagnose dermatophytosis (ringworm)?
A
Wood’s lamp examination
Warm for 5-10 mins, expose hair for 3-5 mins
Apple green fluorescence of hair= positive result
Only 50% of M.canis fluoresce -> false positives and negatives
Could also do trichography
Arthrospores (soap bubbles) surrounding hair shaft, hyphae within hair
DTM (dermatophyte test medium)
Colour change from yellow to red, check every day, false positives and negatives, needs correct culture conditions
External lab fungal culture
Gold standard
11
Q
For how long should you treat systemically against ringworm?
A
Until you have 2 negative cultures 2-4 weeks apart
12
Q
How long is M.canis (dermatophytosis) viable for in the environment?
A
Up to 18 months
13
Q
Which systemic treatments can you use against dermatophytosis (ringworm)?
A
Itraconazole (5mg/kg once a day; 7 days on, 7 days off for cats)
CI: pregnancy, hepatic disease
AE: anorexia, vomiting, hepatic toxicity
Ketoconazole (dogs, 10mg/kg once a day)
CI: pregnancy, breeding animals, hepatic disease
AE: anorexia, vomiting, hepatic toxicity
14
Q
Describe demodicosis
A
Demodex= commensal skin mite
Can be follicular (long-bodied) or surface mites (short-bodied)
15
Q
Which 2 species of demodex mite cause feline demodicosis?
A
Demodex cati (non-pruritic) Demodex gatoi (pruritic, superficial, contagious)
16
Q
For how long should you treat systemically against demodex?
A
Until you have 2-3 consecutive negative skin scrapes taken every 4 weeks
17
Q
What can you use to treat demodex?
A
Amitraz (dogs)
Imidacloprid/moxidectin
18
Q
What are the cutaneous and systemic signs of leishmaniasis?
A
Cutaneous: alopecia, fine silvery scaling, depigmentation, nodules, erosions, ulcers, crusting
Systemic: lymphadenopathy, pyrexia, depression, hepatomegaly, splenomegaly, renal failure, muscle atrophy, polyarthritis, lameness
19
Q
What is sebaceous adenitis?
A
Immune attack on sebaceous glands
20
Q
What is alopecia areata?
A
Lymphocytic attack on hair bulb
21
Q
What is dermatomyositis?
A
Aetiopathogenesis unknown, probably genetically determined immune-mediated disease Dogs 6 months old Collies, shetland sheepdog etc Patchy alopecia on face, extremities Onychodystrophy Give prednisolone
22
Q
What is calcinosis cutis?
When is it usually seen and where?
A
Calcium deposits in dermis and epidermis due to hyperadrenocorticism
Common site= cranial dorsal neck
23
Q
What are the clinical features of non-inflammatory alopecia caused by endocrinopathies?
A
Symmetrical to generalised alopecia Dull dry coat Scaling Comedones Hyperpigmentation Atrophic skin Poor wound healing Post-clipping alopecia
24
Q
Describe sertoli cell tumour
A
More common in cryptorchid testes (retained)
Atrophy of unaffected testicle
Linear preputial erythema
Feminisation syndrome (due to high levels of oestrogen)
Metastasis rare
Neutering is curative
25
Describe telogen defluxion (effluvium)
```
Sudden loss of hair
Occurs 1-3 months after stressful incident (eg pregnancy)
Hairs synchronised into telogen
Shed as new hairs develop
Non-specific hair follicle arrest
```
26
Describe feline paraneoplastic alopecia
Pancreatic and bile duct carcinomas
Alopecic ventrum and legs
Skin shiny and translucent
Surgical excision curative (if early stage)
27
Describe alopecia X
Plush-coated breeds (eg Pomeranian, Chow chow)
Unknown aetiology- local hormone abnormality?
Primary hairs lost first (puppy coat), later complete alopecia and hyperpigmentation (spares extremities)
28
Describe post-clipping alopecia
Unknown pathogenesis, some form of follicular arrest
Plush-coated breeds
Good prognosis
Regrowth 6 months
29
Describe congenital alopecia
Defect in hair follicles, also adnexae, skin, teeth, claws
Dominant, recessive, X-linked
Hairless breeds eg Chinese crested
Dysplastic hair follicle can be prone to secondary bacterial infections
30
Which type of alopecia involves miniaturisation of hair?
Pattern alopecia
31
Describe black hair follicle dysplasia
Familial disorder
Genetic defects in melaninisation
Defect in pigmentation and hair formation
Progressive: born normal, coat changes by 4 weeks, black hairs become dull, hair fracture and loss
32
Describe colour dilution alopecia
Dilute colour coats (blue, fawn)
Genetic defects in melanisation
Macromelanosomes (melanin clumping) -> hair fragility
Progressive changes: hair fracture and loss -> scaling +/- bacterial folliculitis
33
What might you add to an animals diet to aid a dry coat and alopecia?
Essential fatty acids
34
Describe anagen defluxion (effluvium)?
Sudden hair loss (chemotherapy, severe illness)
Damage to growing hair/follicle
Patchy to complete hair loss (fractured/distorted hairs)
Loss of whiskers
35
Describe sebaceous adenitis
Immune-mediated
Genetic predisposition: standard poodles, akitas
Lymphocytic immune attack on sebaceous glands
Alopecia and dull dry coat. Large adherent scales, follicular casts. Bacterial folliculitis.
Treatment: replenish natural skin moisturisers (EFA's, propylene glycol/coconut oil to moisturise skin)
Cyclosporin (variable response)
36
What are the two classifications of alopecia?
Spontaneous: no anima involvement. Various aetiopathogeneses. May be inflammatory (infections, parasites, immune-mediated) or non-inflammatory (hair cycle arrests, hair synthesis defects)
Self-induced: animals removes hair. Pruritis (ectoparasites, allergic skin disease), psychogenic (behavioural, internal pain/inflammation)
37
Give some causes of skin lesions in pigs
Physical (objects), lying on rough surfaces
Vices (biting)
Vector driven (flies and lice)
Infection (bacterial, parasitic, viral, fungal)
Congenital (epitheliogenesis imperfecta)
Toxic (PDNS: porcine dermatitis and nephropathy syndrome)
38
What is the most common flea species amongst cats and dogs?
Ctenocephalides felis ('cat flea')
39
How can you identify flea eggs from regular dirt?
Put on a damp tissue and break up; flea eggs will appear red (blood)
40
What are the primary species of biting lice in dogs and cats?
Dogs: Trichodectes canis
Cats: Felicola subrostratus
41
What is the primary species of sucking lice in dogs?
Linognathus setosus
42
What is the difference between biting and sucking lice?
Biting chew the skin
| Sucking suck blood
43
What is the difference in head shape between biting and sucking lice?
Biting have a wider, rounder head
| Sucking have a thinner, more pointed head
44
What are the two divisions of mites?
| Give some examples of each
```
Surface dwelling (otodectes, Cheyletiella, Trombicula) (long legs)
Burrowing (Demodex, sarcoptes) (short legs)
```
45
What shape are Demodex eggs?
Lemon-shaped
46
Describe lice eggs
Adhere to hair shaft, have a lid (operculum)
47
Give some signs of pruritus
```
Licking
Chewing
Biting
Nibbling
Scratching
Rubbing
Shaking head
```
48
How can you tell if a cat is pruritic?
History of over-grooming, hair balls, clumps of fur around house
Clinical exam: hairs caught in teeth/tongue/faeces
Trichogram: fractured/ blunt hair tips
49
Fleas can can which kind of anaemia?
Iron-deficiency anaemia in young animals
50
Which parasite acts as an intermediate host for fleas?
Dipylidium caninum (tapeworm)
51
Give the clinical signs of FAD
Primary: pruritis, papules, erythema
Secondary: excoriation, alopecia, crusts, pyoderma signs
52
What is FAD?
Allergy to flea saliva
53
Fleas lay eggs within how long of mating?
Mating occurs then eggs are lain within 24 hours of first blood meal
54
Briefly describe the life cycle of a flea
Adults lifespan on host is 7-10 days
Eggs laid on host, fall onto environment
1-10 days later: larvae hatch, feed in environment
5-18 days later: pupae hatch
7-140 days later: adults
55
What percentage of the flea population is adults?
5%
| 95% is in environment (larvae, pupae, eggs)
56
Give the 3 Demodex species which affect dogs
D. canis (limited to hair follicle, commensal)
D. injai (larger than D.canis, reside within sebaceous glands, deep in follicle)
D. cornei (shorter, resides in superficial epidermis)
57
Eggs of mites are found where?
Laid on host, found stuck to hairs or in burrows
58
Briefly describe the mite life cycle
Adult (on host) -> eggs laid on host -> larvae -> nymph -> adult
Takes 2-6 weeks
59
How often should you treat against mites in order to break the life cycle?
Every 2 weeks
60
Give the clinical signs of sarcoptiform mites
Intense pruritis, many crusts, papules, scaling, excoriations, secondary alopecia
61
Which mite causes canine scabies?
| Which areas are affected?
Sarcoptes scabiei var canis
Ears, ventral chest, elbows, hocks
Contagious
Zoonotic
62
What clinical signs does Cheyletiella cause?
| What species does it affect?
Trunk: increased scale, variable pruritis and erythema
Dogs, cats, rabbits
Contagious
Zoonotic
63
Give the two primary species of ear mites
Otodectes spp
- Dogs, cats (contagious)
- Dark brown, waxy discharge
- Also seen on head and neck
Psoroptes spp
- Rabbits
- Profuse waxy scaling
- Painful
64
Which species should Fipronil not be used in?
Rabbits
65
What is Fipronil licensed for?
Fleas, lice, ticks
| Can also be used for Cheyletiella spp
66
What is imidacloprid licensed for? (Advantage)
Fleas and lice
| Licensed in rabbits
67
Permethrin shampoos are toxic to what?
Cats
68
Lime sulfur is used to treat what in cats?
Demodex gatoi
69
Amitraz is toxic to what?
| What is it used to treat?
Cats and chihuahuas
| Mites (Cheyletiella, demodex, sarcoptes), lice
70
Avermectins, e.g. ivermectin or milbemycin, are toxic to which dog breeds?
What are they effective against?
Collies, collie crosses, herding breeds
| Lice and mites eg otodectes, Sarcoptes
71
Describe harvest mites
Neotrombicula
Adults live in vegetation
Larvae are parasitic in late summer/autumn
Dogs, cats, livestock, humans
Possible vector of Anaplasma phagocytophilum & Borrelia burgdorferi
72
How do hookworms enter the host?
Eggs pass out in faeces & hatch to larvae
| Enter host by ingestion or burrowing into skin
73
What is the most common cause of bacterial pyoderma?
Staphylococcus pseudintermedius
Common commensal of mucosa and skin in healthy dogs
Increased carriage with cAD (canine atopic dermatitis) or pyoderma
74
Bacterial pyoderma is classified by what?
Depth of infection
Surface: Superficial epidermis- overgrowth rather than infection as not pyogenic
Superficial folliculitis: epidermis and hair follicles
Deep folliculitis and furunculosis: epidermis, hair follicles, dermis +/- subcutaneous fat
75
Give some examples of underlying disease that may lead to superficial pyoderma
```
Allergy
Ectoparasites
Self trauma
Other infections eg Dermatophytosis, Leishmaniasis
Immune deficiency
Keratinisation defects
Follicular dysplasia
Environment / hygiene issues
```
76
Give some underlying causes of deep pyoderma
```
Extension from superficial pyoderma
Allergic dermatitis and chronic self-trauma
Demodicosis
Foreign body
Trauma
Pressure point pyoderma
Immune deficiency
```
77
What are the clinical signs of deep pyoderma?
Haemorrhagic bullae, crusts, haemo-purulent exudate
Heat, swelling & erythema
Furuncles, nodules & plaques
Thick crusts, ulcers, sinus tracts & exudation
78
Malassezia affects dogs where?
Ears, ventral neck, axillae, groin, perineum and feet
79
Give the clinical signs of Malassezia in dogs
Otitis, erythema, hyperpigmentation, greasy seborrhoea, alopecia
80
Selenium sulfide should be avoided in which species?
Cats
81
How do you treat Malassezia?
Shampoo for skin first line treatment – Chlorhexidine 2% + miconazole 2% (Malaseb shampoo) or chlorhexidine 3% (Microbex)
Other topical preparations for skin and ears
- Clotrimazole, miconazole, nystatin, selenium sulfide (not cats)
- Check authorisation, contraindications, side effects
Systemic antifungals
- Only if severe or chronic & underlying disease addressed
- Check authorisation, contraindications, drug interactions, side effects before use
82
Define canine atopic dermatitis
A genetically predisposed inflammatory & pruritic allergic skin disease with characteristic clinical features, usually associated with IgE, & commonly to environmental allergens
83
Briefly describe the pathogenesis of cAD (canine atopic dermatitis)
1. Defective cutaneous barrier function
2. Microbial colonisation and other flare factors
3. Hypersensitivity reactions to environmental allergens (+/- food)
84
Give the clinical signs of cAD (canine atopic dermatitis)
Pruritus, erythema, papules, saliva stains
Pyotraumatic dermatitis or acral lick dermatitis
Recurrent microbial overgrowths and infections
Alopecia, excoriation, scaling, crusting, hyperpigmentation and lichenification
Skin - dry, moist, greasy or sweaty
Recurrent otitis externa (may be only sign)
Interdigital abscess / furunculosis
85
Give the common features shared by dogs with cAD (canine atopic dermatitis)
```
Onset of signs under 3 years of age
Dog living mostly indoors
Glucocorticoid-responsive pruritus
Affected front feet and/or ear pinnae
Non-affected ear margins or dorso-lumbar area
```
86
What is CARF?
Cutaneous adverse reaction to food (food allergy)
87
How can you diagnose food allergy dermatitis?
Blood tests not reliable
88
How can you diagnose food allergy dermatitis?
Blood and skin tests not reliable
Dietary history
Positive response to 6-8 (12) week diet trial (usually chicken, beef, dairy, cereals-soy)
89
What would you recommend to an owner doing a home-cooked diet trial with a dog suspected of having food allergy dermatitis?
Make it 2/3 carbohydrate, 1/3 protein
| Boil/ microwave, make it in bulk and freeze
90
What would you recommend to an owner doing a commercial diet trial with a dog suspected of having food allergy dermatitis?
Use single protein diets
| Could try a hydrolysed diet (smaller chains of food proteins -> reduced immune response)
91
How can you identify ectoparasites on a pruritic animal?
Tape strip, flea comb, scale exam, hair plucks, skin scrapes
92
Atopic dermatitis produces high levels of which antibody?
IgE
93
How is atopic dermatitis confirmed?
Raised levels of IgE to environmental allergens (75% of cases)
Intradermal skin testing or serology for IgE using dog monoclonal antibody
94
When managing cAD (canine atopic dermatitis), what are the main concerns?
Improving skin barrier function (EFAs, moisturising shampoo)
Controlling flare factors (flea prevention, antiseptics)
Allergen avoidance (household insecticides) and allergen specific immunotherapy (ASIT)
Anti-inflammatory treatment
Will require lifelong therapy
Tailor treatment to individual
95
How can you treat the skin barrier when treating atopic dermatitis?
Systemic EFAs (essential fatty acids)
- supplements or diets
- improves coat quality and decreases trans-epidermal water loss
```
Topical emollients (moisturise and reduce water loss)
- shampoo, conditioner
```
96
Describe allergen specific immunotherapy (ASIT)
Safe, good compliance, inexpensive
Only intervention that may prevent the development of signs and alter the long-term course of the disease
Slow onset: 3-9 months, trial for 12 months
Concurrent anti inflammatory medication usually required
97
Describe the mechanism of action of allergen specific immunotherapy
The aim is to induce or restore tolerance to the allergen by reducing its tendency to induce IgE production. Patients are desensitized through the administration of escalating doses of allergen that gradually decreases the IgE-dominated response. The objective of immunotherapy is to direct the immune response away from humoral immunity and toward cellular immunity, thereby encouraging the body to produce less IgE antibodies and more Th1 regulatory T cells, which secrete IL-10 and/or TGF-beta, which skew the response away from IgE production
98
Which drugs can be given to control flare factors associated with atopic dermatitis?
Systemic glucocorticoids
Adverse effects common (PU/PD, panting, Calcinosis cutis)
Eg methyl-prednisolone, hydrocortisone aceponate
99
Which anti histamine drug can be used when treating canine atopic dermatitis?
```
Cyclosporin
Delayed response (2-3 weeks)
Reduce dose/frequency gradually
```
100
What is a JAK inhibitor?
```
Janus kinase inhibitor, anti inflammatory
JAK inhibitors block cytokine signalling ie interleukins, thereby blocking Th2 cell differentiation and preventing allergic inflammation
Eg Oclacitinib (Apoquel)
```
101
Why do we take samples?
Narrow the differential list
Exclude differentials
Make a diagnosis
102
Which parasite causes 'walking dandruff'?
Cheyletiella parasitavorax
Causes alopecia and thick scaling
Can have small numbers in healthy rabbit; may increase if overweight/bad teeth etc
Eggs are loosely attached to hair shaft
103
What is the proper name for ear mites?
Otodectes cynotis
104
Is a superficial or deep skin scrape required find Cheyletiella?
Superficial- found in crypts of stratum corneum
105
Is a superficial or deep skin scrape required find Sarcoptes mites?
Found in epidermis so deep but not as deep as Demodex
106
Describe Demodex cornei
Related to demodex canis
Lives in superficial crypts of dermis
Can find with tape (don't need to do a skin scrape)
107
Where do you take a hair pluck from when investigating pruritic lesions?
Edge of lesion
| Pull in direction of hair growth
108
What would you see on a trichogram of a dog affected with colour dilution alopecia?
Hair is fractured as it is too big for the follicle
109
How do you do a superficial skin scrape?
Take multiple scrapings from non-excoriated lesions (crusts, scale; elbows and trunk for Sarcoptes)
Remove hair if necessary with curved scissors
Use mineral oil or KOH (warmed if lots of crust)
Remove crust and scale as you scrape (use No10 blade)
Mix on slide in mineral oil or KOH
Add cover slip and examine on low power
110
Compare liquid paraffin to KOH when looking at ectoparasites under the microscope
Liquid paraffin: mites stay alive, messy, poor clearing agent, well tolerated on skin
KOH: mites dead, corrosive, good clearing agent, warming aids digestion
111
How do you do a deep skin scrape?
```
Take multiple scrapes from new lesions
Remove hair if necessary
Squeeze skin
Apply mineral oil or KOH
Scrape (with No10 blade) until capillary ooze
Scoop up, mix on slide (oil or KOH)
Add cover slip and examine on low power
```
112
An ELISA for Sarcoptes measures what?
Serum IgG
113
What are the 3 parts of a Diff-quick stain?
1. Fixative
2. Eosinophilic stain
3. Basophilic stain
114
When investigating skin lesions, when should you culture?
```
Poor response to treatment
If infection recurs
If cytology shows rods and degenerative neutrophils but no bacteria
Multiple treatments
Health care contact
Serious infections
All deep infections
```
115
What is an epidermal collarette?
A circular lesion with a circular rim of scale and/or a peeling edge
116
How does DTM (dermatophyte test medium) work; what do you see? What do you see with contaminants?
Dermatophytes use up protein first (red colour change) then after around 10 days start using up carbohydrate (yellow colour change)
Contaminants= opposite
117
How big should a skin biopsy be when investigating skin lesions?
10 x15 mm
118
Canine atopic dermatitis tends to affect dogs of what age?
6 months to 3 years at onset, most by 6 years
119
Which breed of dog is most prone to atopic dermatitis?
West highland white terrier
120
What is seen on the skin in dogs with Sertoli cell tumour?
Line of erythema between scrotum and penis
121
Squamous cell carcinomas are seen where?
Spontaneous forms:
- Oral
- Ungual (nails)
```
UV induced:
-White hair coat
-Depigmented skin
-Sparsely haired regions (ear tips, nose, around eyes)
-
```
122
Which general history questions should you ask when doing a dermatological consult?
Every animal:
- Attitude and exercise tolerance?
- Appetite and thirst?
- Vomiting or diarrhoea?
Relating to complaint:
- No of stools per day?
- Sneezing or conjunctivitis?
- Seasonal history?
- Neurological signs?
- Previous or concurrent disease?
- Drug history?
- Onset and duration?
- Progressive/intermittent?
- Has there been any changes eg in distribution?
- Itchy?
- Distribution?
- Usual diet?
- Flea treatment?
- Is there worsening/ improvements in certain environments (eg outdoor/indoor/flooring)?
- Travelled/ rescued from abroad? (Leishmaniasis etc)
123
Give some causes of chronic and acute dermatological disease
```
Chronic:
Allergy
Metabolic
Endocrine
Neoplastic
```
```
Acute:
Parasites
Infectious
Immune-mediated
Hypersensitivity
```
124
Give some causes of dermatological disease which is:
Waxing and waning
Progressive
Intermittent
Waxing and waning:
- Allergic
- Immune-mediated
Progressive:
- Metabolic
- Endocrine
- Neoplastic
Intermittent
- Parasites
- Infections
125
Atopic dermatitis tends to flare up when?
Spring to summer
126
Harvest mites and cow pox virus tend to occur when?
Late summer - autumn
127
What is VAS?
```
Visual Analogue Score
Subjective measure of pruritus, out of 10
1= not pruritic
10= constant and severe
2/10 = normal dog
```
128
Where should you look when doing a dermatological clinical exam?
Hair coat
Mucocutaneous junctions and mucous membranes
Skin
Claws, pads, nail beds
Otoscopy (examine good ear first) (may not be possible conscious if animal is painful)
129
What should you describe for each lesion when doing a clinical exam?
Configuration (eg focal)
Morphology (eg alopecia, crusts)
Location (eg caudal dorsum)
Evolution (eg papules turned to crusts)
130
How are crusts formed?
Pustules rupture and form a crust
131
How can you tell if a lesion originates in the dermis or epidermis?
No blood vessels in epidermis, blood vessels in dermis
132
Secondary skin lesions evolve from what?
Primary lesions or external factors
133
What is the difference between the epidermis and dermis?
Epidermis:
- Has four layers
- Keratinocytes
Dermis:
- Has blood vessels and nerves
- Hair follicles
- Sebaceous glands
- Sweat glands
134
How can you tell whether a lesion is haemorrhage or erythema?
Diascopy: hold a slide over the lesion, haemorrhage will not blanch (turn white), inflammatory lesions will (as blood flow is restricted)
135
Chyletiella infestation occurs where?
Dorsal spine
136
Sarcoptic mange infestation occurs where?
Ventral abdomen
137
Flea infestation occurs where?
Lumbar spine, medial thighs, tail base
138
If the dermatological lesions are bilateral and symmetrical, is the cause systemic or from the environment?
What about if it's irregular?
Symmetrical: systemic
Irregular: environment
139
What are follicular casts?
Yellow-brown keratosebaceous material adhered to a hair shaft
Associated with sebaceous adenitis
140
What kind of epithelium is present in the middle ear?
Simple squamous to cuboidal
Few ciliated cells
Mucous-secreting goblet cells
141
The ear canal is lined by modified skin containing what?
Small hairs, ceruminous and sebaceous glands
142
What is the difference between primary, predisposing and perpetual factors?
Primary: underlying cause
Predisposing: factors making a condition more likely to occur in an individual
Perpetuating: factors preventing resolution of a condition
143
Give some primary factors that cause otitis
```
Parasites
Allergic skin disease
Immune-mediated
Neoplasia and polyps
Foreign bodies
Rare/miscellaneous
Epithelialisation defects
Endocrinopathies
```
144
Neoplasms and polyps in the ear arise from where?
| How do they cause otitis?
External ear canal, Middle ear
| Obstruct cleaning mechanisms
145
Give some examples of predisposing factors for otitis
Conformation of ear canal: waxy, pendulous, narrow, hairy
Environment: swimming, high temp and humidity
Iatrogenic: overzealous cleaning, inappropriate cleaning agents
146
Give some commensal microbes that can cause otitis when increased in numbers
Gram positive cocci: staphylococcus pseudintermedius, streptococcis canis
Yeasts: Malassezia pachydermatis
Gram negative baccilli: Pseudomonas aeruginosa, Proteus mirabilis
147
What is otitis media?
Infection of middle ear that causes inflammation and build up of fluid behind the eardrum
148
What kind of things should you ask when taking a history of a pet with otitis?
```
Acute or chronic?
Unilateral or bilateral?
Response to previous therapy?
Any other skin problems?
Any systemic signs?
```
149
What may be the cause of loss of pliability/mobility of the ear?
Neoplasia, severe epithelial hyperplasia, cartilage calcification
150
Which anti-inflammatory drugs can you use to treat otitis?
Corticosteroids, topical and systemic
Anti-pruritic, decrease glandular secretions, exudation, scar tissue and proliferative changes
eg systemic Prednisolone, 0.5-1mg/kg once daily then taper
151
Which diagnostic tests can you use regarding otitis?
Ear sampling (cytology, parasites, culture and sensitivity)
Imaging
Otoscopy and otic lavage
152
Which position is preferred for radiographs investigating otitis?
Dorsoventral
Preferred over ventrodorsal as positioning is easier, bullae are closer to film, allows comparison of canals/bullae/petrous temporal bones
153
How can you resolve perpetuating factors affecting otitis?
Anti-inflammatory drugs
Otic lavage
Anti-microbial agents
Lavage of middle ear
154
Regarding otitis, which factors are indicative of a poor prognosis?
Severe stenosis and fibrosis
Calcification of ear canals and osteomyelitis
Para-aural abscessation
155
How do you treat otitis caused by Malassezia?
Topical antifungal therapy eg itraconazole
156
How can you carry out responsible antimicrobial use?
Avoid antimicrobials unless necessary (check infection present via cytology not culture)
Control inflammation
Avoid systemic antibiotics, use topical antiseptics
157
How do you do an otic lavage?
Remove purulent discharge, flush middle ear
GA and intubation with inflated cuff
Saline flush proximal to distal
Limited by hyperplasia/stenosis (pre-treat with steroids eg prednisolone 7-14 days prior)
Analgesia
158
Most feline otitis cases are due to what?
Polyps and neoplasia
159
Most canine otitis cases are due to what?
Atopic dermatitis
160
How often should you clean a dogs ears?
1-2 times a week
161
Otitis: What kind of topical maintenance therapy should be used in an animal with dry wax and prone to Malassezia?
Ceruminolytic agents eg propylene glycol
162
Otitis: What kind of topical maintenance therapy should be used in an animal with moist ears and those prone to bacterial infection?
Low viscosity cleaners for flushing
| Antimicrobial agents eg chlorhexidine
163
Otitis: What kind of topical maintenance therapy should be used in an animal where the primary factor is allergic skin disease?
Topical corticosteroid to control ongoing inflammation
164
Give some adverse effects of otitis treatments
Ear canal and/ or tympanic membrane trauma
Vestibuar syndrome
Horner's syndrome
Deafness
Topical agents: irritation, ototoxicity, sensitisation
165
Notoedric mange affects which part of a cat?
Face
166
Feline cutaneous reaction patterns are most commonly seen with which kind of dermatitis?
Hypersensitivity
- Flea bit hypersensitivity
- Feline atopic dermatitis (non-flea, non-food)
- Cutaneous adverse food reaction (CAFR)
167
What are the 4 feline cutaneous reaction patterns?
Symmetrical Alopecia
Head and neck pruritus
Military dermatitis
Eosinophilic granuloma complex (Eosinophilic plaque/granuloma/ indolent ulcer)
168
What is the most common type of hypersensitivity dermatitis in cats?
Flea bite hypersensitivity
169
Briefly describe symmetrical alopecia in cats
Most commonly self-induced due to pruritus
- Non-inflamed
- Areas cat can reach (symmetrical)
- Ventral abdomen, lateral thorax, caudal thighs
- Often linear
- Loss of hair length not loss of hair growth
170
What are the signs of self-induced alopecia in cats?
```
Short spiky hairs on physical exam
Vomiting fur balls
Hair in faeces
Embedded hair in gingival sulci and/or tongue
Clumps of hair in cats environment
Trichogram (broken/frayed tips)
```
171
Give some possible causes of head and neck pruritus in cats
Parasites (otodectes, neotrombicula)
Infectious (bacteria, Malassezia)
Less likely: irritant contact dermatitis, behavioural, oro-facial pain syndrome
172
Describe head and neck pruritus in cats
```
Pruritus
Self-excoriation (linear)
-Erosions
-Ulcers
-Crusts
Face, cranial pinnae, neck
```
173
Military dermatitis in cats is seen where?
Dorsal lumbosacral area
Dorsal flanks and neck
(Caudiomedial thighs, ventral abdomen)
174
Give some differential diagnoses for military dermatitis
```
Cheyletiella
Lice
Otodectes
Neotrombicula
Endoparasites
Bacterial pyoderma
Dermatophytosis (ringworm)
Hypereosinophilic syndrome
Drug reaction
Fatty acid or other dietary deficiencies
Pemphigus foliaceus
```
175
Give some proposed aetiological triggers for eosinophilic granuloma complex
```
Allergens (food, flea, environment-atopic dermatitis)
Viral eg feline herpes virus
Bacterial
Fungal
Parasites eg cheyletiella
Foreign body
```
176
Where are eosinophilic plaques seen (cats)?
Abdominal and inguinal skin
Medial and caudal thighs
Neck
Interdigital skin
Highly pruritic
177
Where are Eosinophilic granulomas seen (cats)?
Caudal thighs (spontaneous regression, genetic?)
Hard/soft palate +/- necrosis
Swelling of chin (asymptomatic)
Not pruritic
178
Describe the appearance of an Eosinophilic granuloma (cats)
Alopecic, raised plaque/nodule
| Intact skin or eroded-ulcerated (Ulcerated lesions have central white accumulations)
179
Describe an Eosinophilic ulcer in cats
Upper lip, near canines
Well circumscribed, red/brown ulcer with raised border
Non-pruritic
Non-painful
180
What are the differentials for Eosinophilic ulcer in cats?
SCC (squamous cell carcinoma), trauma and rare genetic disease
181
What is cyclosporin?
Immunosuppressive drug
182
What causes ringworm in cats?
Microsporum canis
183
Pediculosis refers to skin disease caused by what?
Lice
184
Mange refers to skin disease caused by what?
Mites
185
Which species of lice are found in horses?
| Where abouts?
Haematopinus asini
Sucking louse, feeds on blood
Mane and tail, fetlock and pastern
Werneckiela
Biting louse, feeds on epidermal debri
Dorsolateral trunk
186
Lice in horse are more common in which season?
Winter
187
How can you treat lice in horses?
Pyrethrins, pyrethroids, permethrin, fipronil
188
Which mite species are found in horses?
Chorioptes equi: distal limbs, intense pruritus, draft breeds, winter
Sarcoptes scabiei: head, neck, ears -> entire body, difficult to see on skin scrapings
Psoroptes equi: forelock, mane, tail -> trunk, ears- head shaking
Trombiculidiasis: larvae of free-living adult mites, papules with small orange larvae in centre, face, distal limbs, ventral thorax, abdomen
Demodex: D.equi-body D.caballi-eyelids, muzzle. Rare
189
How do diagnose mites in horses?
Skin brushings (skin scrapings not effective)
190
How do you treat mites in horses?
Systemically: Avermectins (not licensed)
Topically: lime sulphur
Treat at 2 week intervals (life cycle)
191
Give some non-allergic differentials for self-induced symmetrical alopecia in cats
Pruritic: ectoparasites (eg lice, cheyletiella), infectious (bacterial folliculitis)
Non-pruritic: behavioural (anxiety, pain eg orthopaedic, UTI)
191
What are the 3 presentations of eosinophilic granuloma complex in cats?
Eosinophilic plaque
Eosinophilic granuloma
Eosinophilic ulcer
192
What should you also check if you find demodex on a horse and why?
Immunosuppression, as demodex is rare in horses
193
When are ticks most commonly seen on horses?
Spring and summer
194
What is another name for oxyuris equi?
Pinworm
| Causes perianal pruritus
195
What is Onchocerca cervicalis?
Where do adults live?
Where do microfilarie live?
Horse nematode
Live in nuchal ligament
Microfilarie migrate to the skin -> hypersensitivity
196
What are the risk factors for Culicoides (sweet itch) in horses?
Standing water, dawn and dusk, no wind
197
What is the difference between scaling and crusting?
Scaling is dry and grey, whereas crusting is yellow-brown and wet/damp
198
What is the difference between erosion and ulceration?
Erosion is superficial, ulceration is deeper
199
Describe dermatophilosis ('Rain Scald') in horses
```
Dermatophilus congolensis. Gram +ve facultative anaerobe
Chronic moisture and skin damage
Crusts, moist matts of hair
Back, gluteal area, face, neck
Treat with antibiotics
```
200
What are the 2 main genera of ringworm (dermatophytosis)?
Trichophyton, microsporum
201
How do you treat ringworm in horses?
Topical antifungals eg Miconazole
202
What are the two causes of photosensitisation in horses?
Hepatogenous (liver disease)
| Ingestion/application of photodynamic agent
203
'Warbles' (seen in horses) are the larval stages of which flies?
Hypoderma bovis and lineatum
204
What is a dentigerous cyst (horse)?
"Tooth in ear"
Cyst contains all/part of tooth
Horse was born with it
205
What is an atheroma (horse)?
'Nasal Inclusion Cyst'
Non-painful, located in false nostril, a blind pouch in the outer wall of the nostril
Filled with sebaceous material
Present at birth
206
What is a dermoid cyst (horse)?
Teratoma
Contains epidermis, hair follicles, sebaceous glands
Derived from residual embryonic cells
207
What is a vascular hamartoma (horse)?
Resembles a neoplasm, benign
| Composed of tissue elements normally found at that site, but which are growing in a disorganised mass
208
What clinical signs might an owner perceive as pruritus?
```
Chewing
Nibbling
Licking
Scratching
Rubbing
Shaking head
Biting
```
209
Fleas are the intermediate host of what?
Dipylidium caninum
210
Where are lesions caused by Cheyletiella found?
Trunk
211
Psoroptes ear mites are found in which species?
Rabbits
212
What are 'hotspots'?
Pyotraumatic or moist dermatitis
Focal to multifocal, well-demarcated, moist, flat eroded lesion with erythematous halo
Exacerbated by continued licking or chewing
Dogs
