SA dermatology Flashcards
what is the most common feline infection?
cat bite abscesses
what are some common pitfalls in dermatology?
disregarding history
failure to appreciate clinical signs
errors when taking diagnostic samples, allergy testing, interpreting results and therapy
what is the most important things to ask the owner for during history taking?
their chief complaint
why is it important to ask the owner for their chief complaint?
narrows the differential list (such as is it pruritic or not)
builds vet-client bond
gives the reason they are presenting
what signalment should be collected?
age, breed, sex
coat colour
weight (change)
affected relatives
with regards to when the disease started, what information is it important to collect?
age at which it started
what a classical conditions seen in very young dogs (<1 year)?
parasites
congenital
food-induced atopic dermatitis
what a classical conditions seen in adult dogs?
immune mediated
endocrine
food-induced atopic dermatitis
what a classical conditions seen in elderly dogs?
neoplastic
metabolic
food-induced atopic dermatitis
what breed of dog is predisposed to getting atopic dermatitis?
West Highland White terriers
what should be obtained in a general history?
behaviour appetite/thirst vomiting/diarrhoea stools sneezing seasonal history drug history
what three things need to be determined in a dermatological history?
onset
duration
progression
with regards to onset, what can the causes of dermatological issues be split into?
chronic and acute
what are some chronic causes of skin problems?
allergy
metabolic
endocrine
neoplastic
what are some acute causes of skin problems?
parasites
infectious
immune-mediated
hypersensitivity
what are the three ways duration of a dermatology issue can be split?
waxing/waning
progressive
intermittent
what are some causes of skin disease that waxes/wanes?
allergic
immune-mediated
what are some causes of skin disease that are progressive?
metabolic
endocrine
neoplastic
what are some causes of skin disease that are intermittent?
parasites
infections
what is the saying to determine whether pruritus is a primary sign?
is it a rash that itches or an itch that rashes
what scale is used as a subjective measure of pruritus?
visual analogie scale
what is it important to find out about previous/current treatments?
what’s the animals response to it was
adverse effects
compliance - animal/owner
dose and duration
what is it important to find out about flea prevention?
products used
frequency of use
last application
other in contact animals
what should be asked about when taking a diet history?
proteins/carbs in the usual diet
treats and table scraps
edible toys
flavoured vitamins/medications
why is important to find out the products used for flea treatment?
they are often effective against other parasites so can to reduce the differential diagnosis list
on a dermatological examination what need to be assessed in detail?
mucocutaneous junctions and MM hair coat skin claws, pads, nail beds ear pinnae and canals
how many layers does the epidermis have?
four
what is found in the dermis of skin?
blood vessels/nerves
hair follicles
sebaceous glands
sweat glands
what are some examples of primary lesions?
papules pustules pigmented macules papular-macular rash alopecia erythematous plaques
what is a plaque?
lots of pustules joined together
what are some examples of secondary lesions?
lichenification thin skin crusts and erosion excoriation epidermal collarettes scale ulcer comedones
what do epidermal collarettes happen secondary to?
pustules
what is the difference between erosion and ulcers?
erosion - loss of epidermis above the basement membrane
ulcers - loss of epidermis through the basement membrane (bleeding)
describe how a papule evolves
papule to pustule to crust to epidermal collarette to pigmented macules
what does bilateral symmetrical distribution of lesions suggest?
an inside-out disease
what does an irregular distributions of lesions suggest?
an outside-in disease
what should be assessed on coat examination?
change in colour change in texture ease of epilation broken hairs follicular casts
what 4 points must be described for each lesion?
configuration
morphology
distribution
evolution
what are the three key facts that should be known at the end of the dermatology consult?
age of onset
presence/absence of primary pruritus
distribution/types of lesions
what are the major presenting signs of dermatological problems?
pruritus alopecia crusting scale nodules
what is the unique ways of presenting skin disease in cats?
feline cutaneous reaction patterns
what are the four feline cutaneous reaction patterns?
military dermatitis
eosinophilic granuloma complex
head and neck pruritus
symmetrical alopecia
what are the types of eosinophilic granuloma complexes?
eosinophilic granuloma
indolent ulcer
eosinophilic plaques
what are some parasites that will cause pruritus in cats?
Cheyletiella Felicola subrostratus Notoedres cati Sarcoptes scabei fleas Neotrombicula Demodex gatoi
what are two infections that can cause pruritus in cats?
superficial bacterial pyoderma
Malassezia dermatitis
what must be considered when attempting to diagnose ectoparasites?
where they are found in the skin
how can ectoparasites found on the skin surface be sampled?
brushing, wet paper test, sellotape impression
how can ectoparasites found in the shallow surface in the epidermis be sampled?
superficial skin scrapes
how can ectoparasites found in deeper skin be sampled?
deep skin scrapes
hair plucks
biopsy
is Demodex gatoi contagious?
yes
what are the clinical signs of Demodex gatoi?
pruritus
head, neck and truncal alopecia
how can Demodex gatoi be diagnosed?
tape cytology
skin scrapes have very poor sensitivity for this
how can Demodex gatoi be treated?
selamectin
fluralaner
lime sulphur dip
(treat all in contact cats)
where does Notoedres cati initially infect?
head and ears but can spread to rest of the body as it becomes more chronic
how can Notoedres cati be differentiated from sarcoptic mange?
Notoedres is smaller and has a dorsal anus
what parasite can cause alopecia?
Demodex cati
what infections can cause alopecia?
superficial bacterial pyoderma
dermatophytosis
what endocrine disorder can cause alopecia?
spontaneous/iatrogenic hyperadrenocorticism
where on the body is Demodex cati found?
eyelids, periocular, head, neck
Demodex cati is a commensal, what are some issues that could cause it to become a problem?
immunosuppression
FIV/FeLV
diabetes
squamous cell carcinoma
what are the clinical signs of Demodex cati?
comedones, alopecia, erythema, crusts, scale, variable pruritus, secondary infection
what can be used to treat Demodex cati?
isoxazolines
lime sulfur dips
how is Demodex cati diagnosed?
deep skin scrape - sedation/analgesia required
what should be seen after a deep skin scrape?
blood/haemorrhage confirms the scrape is deep enough
what is paraneoplastic alopecia of cats associated with?
pancreatic or bile duct tumours
where is alopecia seen in paraneoplastic alopecia cats?
ventral body, neck, chin, body, inner legs, feet, nasal plant, footpads
how is the skin of paraneoplastic alopecia cats described?
thin and shiny
describe the process of skin biopsy
place punch firmly on the skin and twist 180 degrees and push
what parasites will cause scaling and greasy cats?
Cheyletiella
Felicola subrostratus
Notoedres cati
Sarcoptes scabei
other than parasites what conditions can cause scaling/greasy disease in cats?
neoplasia
keratinisation disorders
infections
what is the main neoplasia causing greasy/scaly cats?
thymoma
what are the clinical signs f thymoma induced exfoliative dermatitis?
diffuse, non-pruritic erythema and exfoliation
possible alopecia
respiratory compromise - problems
how can thymoma induced exfoliative dermatitis be diagnosed?
biopsy (skin)
chest radiograph
what can be used to treat thymoma induced exfoliative dermatitis?
immunomodulatory drugs (prednisolone) surgery
what cat breed is predisposed to idiopathic facial dermatitis?
Persian
what are the clinical signs of idiopathic facial dermatitis?
tightly adherence greasy black scales
pruritus
what can be used to treat idiopathic facial dermatitis?
reduce inflammation - cyclosporin
remove grease - keratolytic shampoos
anti-yeast therapy
feline acne is a common keratinisation disorder, what are the clinical signs?
can be asymptomatic
dark, waxy scales and comedones
what can be used to treat feline acne?
topical antiseptics
anti-keratinolytics
good hygiene/washing
what breeds of cat are predisposed to Malassezia dermatitis?
Devon rex
Sphinx
Persian
what are the possible clinical signs of Malassezia dermatitis?
seborrhoeic dermatitis
otitis
keratinisation disorder
what viral infections of cats can cause crusts?
pox virus
herpesvirus
calicivirus
what cats is cow pox mainly seen in?
rural male cats that hunt
what happens in most cases of cow pox in cats?
spontaneous resolution if around 4 weeks
when may spontaneous resolution of cow pox in cats not occur?
in immunocompromised cats
what should not be used to treat cow pox in cats?
corticosteroids - fatal
what can be used to treat cow pox?
supportive therapy - fluids, appetite stimulation, tube feeding
(can’t kill the virus)
manage secondary infection and respiratory disease
where is feline herpes virus lesions normally seen?
eyes and nose (butterfly pattern)
what can trigger feline herpes virus?
stress and glucocorticoids
what areas of the skin is mosquito bite hypersensitivity usually found?
nose, ears and feet (where skin is thin and hair is sparse)
what are some clinical signs of mosquito-bite hypersensitivity?
papules - develop into crusts
alopecia, depigmentation and ulcers
peripheral lymphadenomegaly
what type of disease is feline pemphigus foliaceus?
auto-immune
where on the body is feline pemphigus foliaceus usually seen?
head, ears, nipples and feet
what are the clinical signs of plasma cell pododermatitis?
soft swollen pads with scaling
ulceration
can have gingival stomatitis or nasal lesions
what is used to diagnose commensal skin infections?
cytology
why can culture be used to diagnose commensal organisms?
they are present on skin whether there is disease or not
what is the most common commensal bacteria that causes skin disease?
Staphylococcus pseudintermedius
what is the most common commensal fungi that causes skin disease?
Malassezia pachydermatis
how are pathogenic skin infections diagnosed?
culture
what is the name for a bacterial skin infection?
bacterial pyoderma
what are some common causes of secondary bacterial pyoderma?
allergy ectoparasites self trauma immune deficiency (endocrinopathy) keratinisation defects
what are some bacteria that can cause bacterial pyoderma other than S. pseudintermedius?
S. aureus
S. schleiferei
S. canis
what are the three depths that bacterial pyoderma can be classified to?
surface
superficial
deep
what layer is surface bacterial pyoderma found on?
superficial epidermis
where in the skin is superficial bacterial pyoderma found?
epidermis and hair follicles
where in the skin is deep bacterial pyoderma found?
epidermis, hair follicles, dermis, subcutaneous fat
what causes surface bacterial pyoderma?
overgrowth of bacteria (not infection!!)
what are the three clinical presentations of surface overgrowth?
hotspots
skin fold pyoderma
bacterial overgrowth
what breeds of dog are predisposed to hotspots?
densely coated breeds - Rottweilers, golden retrievers…
where are hotspot lesions usually seen?
cheek, neck and rump
how are hotspot lesions described?
well demarcated flat eroded moist lesions with erythematous halo
why do hotspot lesions develop so quickly?
due to self trauma because of pruritus and pain
what can be done to treat hotspots?
clip, clean, topical antiseptic/antimicrobials
what is another name for hotspots?
pyotraumatic dermatitis
what is the name for skin fold dermatitis?
intertrigo
what causes intertrigo?
compromised barrier due to friction, altered micro-climate, loss of normal ventilation and accumulation of fluids
what is done to treat skin fold dermatitis?
topical antiseptics and antimicrobials
clean areas
treat underlying cause
where on the body us bacterial overgrowth usually seen?
ventral trunk and interdigital spaces
what type of discharge does Malassezia overgrowth produce?
brown and greasy
what types of lesions are acetate tape strips used for?
dry, erythematous, scales and alopecic skin
where is superficial dermatitis usually found?
hair follicles
what are the primary lesions of a superficial folliculitis?
follicular papule and pustules
what is the most common bacteria causing superficial folliculitis?
S. pseudintermedius
what are the clinical signs of superficial pyoderma?
erythema follicular papules/pustules crusts epidermal collarettes erosion hyper pigmented macules
what clinical sign is seen in short coated puppies with superficial pyoderma?
moth eaten appearance
annular macule of alopecia
what is the name given when follicles rupture due to deep pyoderma?
folliculitis and furunculosis
what are the clinical signs of deep pyoderma?
heat, swelling, erythema, furuncles, nodules, bull, plaques, sinus tracts, ulcer, exudation, crusts
more systemic signs - fever, pain, lymphadenopathy
with regards to deep pyoderma, what type of exudate is usually seen?
haemorrhagic to Haemonchus-purulent
what are the methods of sampling that can be used for cytology?
direct impression smear
cotton swab smear
adhesive tape strip
fine needle aspirate
what are the two key findings on cytology of pyoderma?
degenerative neutrophils and intracellular bacteria
what are the key morphological features of degenerative neutrophils?
lose cytoplasmic outline
light pink staining
nucleus streaming
when should culture and susceptibility be performed?
recurrent/chronic infections poor response to therapy rod shaped or unusual organisms on cytology degenerative neutrophils but absence of bacteria on cytology deep infections non-healing wounds post-op or nosocomial infections life threatening infections
what is the culturing technique for superficial infections?
rupture/sample intact lesion if present
sample erosion under a crust or collarette
what is the gold standard for culturing technique for deep infections?
use a fresh tissue biopsy
other than a fresh tissue biopsy what can be used to culture deep infections?
rupture of intact lesions and swab
what should be used to treat all bacterial pyodermas? and why?
topical therapy - less antimicrobials needed
what should be used as the first line of treatment for Malassezia dermatitis?
chlorhexidine shampoos
what is pruritus?
the unpleasant sensation that elects the desire or reflex to scratch, rub, lick, chew or roll
how does pruritus manifest in cats?
reaction patterns
behavioural changes
what are the 4 reaction patterns of cats?
alopecia
head and neck pruritus
military eczema
eosinophilic granuloma complex
in cases where owners don’t realise/deny their dog is itchy, what can be looked at to confirm if they are or not?
feel for broken hairs
look for saliva stained paws (brown discolouration)
what tests can be done to identify pruritus?
trichography
cytology
what is trichography?
examination of hair plucks
what is examined during trichography?
stage of growth
structure of melanosomes
pathological changes
attached/associated organisms and parasites
what structures can pathological changes be looked for during trichography?
bulb
shaft
tip
external surface
what can be seen associated with the hair during trichography?
Demodex mites
dermatophytosis
how can cytology be used to confirm the presence of pruritus?
during licking/chewing oropharyngeal bacteria will be deposited on the skin, these can then be identified
what oropharyngeal bacteria is looked for to confirm the presence of saliva on the skin?
Conchiformibius
when using assessment charts for pruritus, what must be told to the owner before they give their grade of pruritus?
what grade the pruritus was previously - can tell whether it has improved or not
what are some superficial skin infections that cause pruritus?
superficial bacterial pyoderma
Malassezia dermatitis
name some ectoparasites that can cause pruritus
Sarcoptes scabei Notedres cati Demodex gatoi flea Cheyletiella Neotrombicula autumnalis lice Otodectes cyanotis
what allergies can cause pruritus?
flea allergy
cutaneous adverse food reaction
atopic dermatitis
feline atopic skin syndrome
name two immune mediated/auto-immune diseases that can cause pruritus
Pemphigus foliaceus
sebaceous adenitis
what are some viral disease that may cause pruritus?
cow pox
feline herpes virus
FeLV/FIV
how does superficial pyoderma present?
spots, crusts and patchy hairloss
what areas is superficial pyoderma most common in?
folded (intertrignous) areas
naturally alopecic skin
what are the clinical signs of Malassezia dermatitis?
erythema
pruritus
malodor
dark coloured exudate
what breeds are predisposed to Malassezia dermatitis?
bassets
rex cats
what is the scientific name for fleas?
Ctenocephalides felis
what must happen for a flea to lay eggs?
they must have a blood meal
what is a crucial step in the control of fleas?
stopping them before they have their blood meal
how do fleas cause pruritus?
annoyance
flea allergic dermatitis (type I and Iv hypersensitivity)
what are the primary clinical signs of fleas?
pruritus
papules
erythema
what cutaneous reaction patterns are seen in cats with fleas?
all four cutaneous reaction patterns
what are the secondary clinical signs of fleas?
excoriation
alopecia
crusts
pyoderma signs
what areas of a dogs body are fleas seen on?
caudodorsal and ventral abdomen
what are the ways in which fleas can be diagnosed?
direct observation
wet paper test
coat brushing/sellotapes
how can fleas be treated/controlled?
adulticides to all animals
environmental control - cleaning, environmental sprays…
anti-pruritic therapy if required
what causes sarcoptic mange?
Sarcoptes scabei
what animals is sarcoptic mange most commonly seen in?
immunosuppressed dogs and cats
how long is the lifecycle of Sarcoptes scabei?
3 weeks
how does sarcoptic mange first present?
as a pruritic disease that then progresses to crust formation
what type of reaction do sarcoptic mites cause?
a type I hypersensitivity
how long after initial infestation does pruritus begin in sarcoptic mange?
3-4 weeks
where are female Sarcoptes scabei found?
tunnels in the stratum corneum
where on the body is carcoptic mange usually seen?
ears, ventral neck, elbows and hock
what are the primary clinical signs of sarcoptic mange?
severe pruritus
papules
erythema
what are the secondary clinical signs of sarcoptic mange?
excoriation
alopecia
crusts
pyoderma signs
what can be used to diagnose sarcoptic mange?
skin scrapes
test treatment - most common
serology (variable sensitivity)
what type of skin scrub is done for sarcoptic mange?
superficial scrape on papules or crusted area
what are common topical/oral therapies for treating sarcoptic mange?
moxidectin, selemectin, isoxazolines
anti-pruritic initially
what breeds are predisposed to Demodex injai?
terriers
what are the clinical signs of Demodex injai?
greasiness, truncal pruritus, alopecia
secondary bacterial infection
where does Demodex injai live?
deep in follicles and sebaceous glands
how is Demodex injai diagnosed?
deep skin scrapings and biopsy
what are Neotrombicula autumnalis also known as?
harvest mites
what do harvest mites look like on the skin?
orange dots
what season is Neotrombicula autumnalis seen?
June to September
how can harvest mites be treated?
avoidance is best!!
fipronil spray on legs
how many legs does the larvae of harvest mites have?
6
what are ear mites called?
Otodectes cyanotis
how can Otodectes cyanosis be diagnosed?
direct observation of photophobic mites
ear wax examination
what drug must not be put in the ear to treat Otodectes cyanotis?
fipronil
what are the clinical signs of Cheyletiella?
scaling affecting the trunk and sometimes the head
Miliary dermatitis in cats
variable pruritus
how can Cheyletiella be diagnosed?
coat brushing
skin scrapes of scaly areas
is Cheyletiella zoonotic?
yes
what are the three types of lice found in dogs?
Felicola subrostratus
Trichodectes canis
Linognathus setosus
what are the clinical signs of lice?
alopecia
scale and excoriation
anaemia in severely effected puppies
what are some examples of hypersensitivity reactions?
atopic dermatitis - food and environmental
inspect bite
contact
what are the characteristic features of Pemphigus foliaceus?
sterile pustules/crusts affecting the face, nose and feet
why can obtaining clinical history of dermatological disease in cats be challenging?
they have a solitary nature and are secretive so clinical signs may go unnoticed
what 4 broad things can trigger feline allergy?
food allergens
flea allergens
intrinsic allergens (self-proteins)
extrinsic allergens
what factors can contribute to feline allergy?
skin barrier dysfunction immune dysregulation allergen sensitisation environmental factors stress microbes
how can food allergens manifest in cats?
allergic skin disease (with/without GI disease)
how can flea allergens manifest in cats?
allergic skin disease
what can intrinsic and extrinsic allergens manifest as in cats?
asthma or allergic skin disease
define feline atopic syndrome (FAS)
allergic disease associated with environmental allegens, food allergy and asthma that may be associated with IgE antibodies
define feline atopic skin syndrome (FASS)
inflammatory and pruritic dermatitis involving a spectrum of non-specific cutaneous reaction patterns that may be associated with IgE to environmental allergens
what can mimic or contribute to feline atopic skin syndrome?
food or flea allergies
define feline food allergy (FFA)
any disease (including FASS) attributable to immunological reactivity to ingested food
what does the inflammatory response of FAS involve?
eosinophils and lymphocytes
what does extrinsic disease of FAS involve?
IgE and is demonstrable
what is the typical history of a cat with FASS?
young age of onset (6 months to 3 years)
presence of pruritus
absence of contagion
response to corticosteroids
what is a major characteristic of FASS lesions?
they are pruritic
what are the primary lesions of FASS?
erythematous papules and patches
what are the secondary lesions of FASS?
excoriations
lichenification
hyperpigmentation
where on the body are lesions of FASS usually distributed?
feet, eyes, ears, chin, tail base
what other diseases/problems must be eliminated before diagnosing a cat with FASS?
fleas, parasites, infections and food allergy
how can pruritus be confirmed in cats?
linear excoriations short/spikey hairs fur balls and hair in faeces hair in gingival sulci/tongue clumps of hair in cats environment trichogram
what are the 4 cutaneous reaction patterns?
self induced alopecia
head/neck pruritus
military dermatitis
eosinophilic granuloma complex
what are the 3 eosinophilic granuloma complexes?
eosinophilic plaque
eosinophilic granuloma
indolent ulcer
what does the skin of self-induced alopecia in cats look like?
non-inflamed and normal with hair removed
where will self-induced alopecia be seen?
areas that cat can scratch - ventral abdomen, lateral throat, caudal thight
non-pruritic self-induced alopecia is uncommon, what could cause this?
pain and anxiety
what are the parasitic differentials for self-induced alopecia?
Cheyletiellosis Trombiculosis Otoacariasis Pediculosis Demodex gatoi
what are the parasitic differentials for head and neck pruritus?
otoacariasis
trombiculosis
notoedric and sarcoptic mange
what are the microbial infections that could lead to head and neck pruritus?
bacterial infection
Malassezia dermatitis
dermatophytosis
what neurological disease can cause head and neck pruritus?
oro-facial pain syndrome
how does miliary dermatitis present?
multiple crusted papules on the dorsum of a cat (also seen on caudomedial thighs and ventral abdomen)
what are the parasitic differentials for miliary dermatitis?
cheyletellosis pediculosis otoacariasis neotrombiculosis endoparasites
what are two differentials for miliary dermatitis that aren’t microbial infections or parasites?
drug reactions
fatty acid/dietary deficiency
where are eosinophilic plaques usually seen?
abdominal/inguinal skin, interdigital skin, neck, thighs
what is the clinical presentation of eosinophilic plaques?
highly pruritic
raised, alopecic, erythematous eroded to ulcerated plaques
how do eosinophilic granulomas present?
variably pruritic
alopecic raised plaques/nodules
intact skin to eroded/ulcerated - central white accumulations
are indolent ulcers pruritic or painful?
neither pruritic or painful
describe the appearance of indolent ulcers
well circumscribed, red/brown ulcer with raised border
where are indolent ulcers always seen?
upper lip
what are some possible infectious differentials for eosinophilic granuloma complexes?
deep bacterial infection deep mycosis dermatophytic granuloma cowpox cutaneous herpes
what are some non-infectious differentials for eosinophilic granuloma complexes?
neoplasia
foreign bodies
genetics
sterile granulomatous disease
what is the name of the criteria used to diagnose FASS?
Favrots criteria
what are some common diagnostic tests used to rule out differentials for FASS?
impressions smear cytology flea combing scale examination skin scrapings trichography trial treatment biopsy
how long are flea treatment trials run for?
6-8 weeks
what other differentials can be ruled out with careful selections of flea treatment trials?
Demodex
other parasites
what are the criteria for flea treatment trials?
adulticide with rapid kill speed
insect growth regulator with residual action
safe and easy to administer
treat all at home contacts
how long should an elimination diet for suspect food induced FAS be run?
8-12 weeks
what are the two options for elimination diets?
novel home cooked diet
commercial novel hydrolysed or single protein diet
what are the recommended treatments for FAS?
systemic glucocorticoids
ciclosporin
what are the 4 treatment groups for multimodal management of FASS?
skin barrier care
anti-inflammatory and immunomodulators
allergen avoidance
control flare factors
what can be used for skin barrier care in the multimodal management of FASS?
essential fatty acids
topical lipid complexes
moisturising shampoos
what is allergen specific immunotherapy used for?
reduce flares associated with exposure to environmental allergens
when should symptomatic treatment of FASS be started?
at the beginning of the diagnostic trial
what are some anti-inflammatories/immunomodulators that can be used in FASS cases?
prednisolone
methylprednisolone
dexamethasone
(these are glucocorticoids)
what are some patient factors that treatment needs to be tailored for?
severity of disease
general health status
home environment
predisposition to microbial infections
what is a particular side effect in cats of long term glucocorticoid administration?
diabetes mellitus
what are the most common adverse effects of cyclosporin administration?
GI signs
weight loss
when are antihistamines usually used for FASS?
early/mid disease due to the limited benefits of them in cats
what is alopecia?
the loss of or absence of hair
what are the two types of alopecia?
spontaneous
self-induced
how can the absence of pruritus in alopecic patients be confirmed?
feel of coat (rough/smooth)
saliva stains
cytology for Conchiformibius
trichograms
what are some symmetrical alopecias?
follicular dysplasia canine recurrent flank alopecia colour dilution alopecia hyperadrenocorticism hypothyroidism pattern alopecia sebaceous alopecia
what needs to be found out about the character of the alopecia?
whether it is partial or complete
if it is in regular or irregular patches
what is the most common cause of bacterial folliculitis?
Staphylococcus pseudintermedius
how is the alopecia associated with bacterial folliculitis distributed?
focal to multifocal patches
what clinical signs if bacterial folliculitis associated with?
pruritus alopecia scale (epidermal collarettes) crusts deep infection (nodule swelling)
what can be done to diagnose bacterial folliculitis?
impression smear cytology
what is the most common cause of ringworm in cats/dogs?
Microsporum canis
what is ringworm also known as?
dermatophytosis
what animals is ringworm most commonly seen in?
young or immunocompromised animals
what breed of acts are predisposed to ringworm?
Persian
what are possible formats for dermatophytosis?
bedding
grooming equipment
collars/leads
any surface
what are the clinical signs of ringworm?
multifocal circular patches that often have hyperpigmentation
follicular casts
where on the body is dermatophytosis often found?
head, ears and chin
how can dermatophytosis be diagnosed?
Mackenzie (toothbrush) sample woods lamp exam trichography in house DTM external lab fungal culture
how is a woods lamp examination carried out?
warm lamp for 5-10 minutes and expose hair for 3-5 minutes
apple green fluorescence of hair if dermatophytosis is present
what is looked for on a trichograph to confirm dermatophytosis?
arthrospores (soap bubbles) surrounding hair shaft and hyphae within the hair
what is a Mackenzie (toothbrush) sample?
use a cheap toothbrush with nylon bristles
brush effected areas of the animal
submit the toothbrush to the lab or inoculate onto fungal culture medium
what can be done to treat dermatophytosis?
topical treatment - chlorhexidine/miconazole shampoo, lime sulphur dip, enilconazole (dogs)
why does dermatophytosis need to be treated?
to decrease contamination and environmental spread (disease revolves spontaneously within 12-20 weeks)
why is clipping for treatment of dermatophytosis controversial?
it can cause microtrauma which can the further increase infection
how often does chlorhexidine/miconazole shampoo for dermatophytosis need to be used?
2-3 times a week
how often does lime sulphur dip for dermatophytosis need to be used?
once a week
how often does enilconazole for dermatophytosis need to be used?
every 4 days
how long is Mycosporum canis viable for in the environment?
up to 18 months
what can be done to decrease the environmental contamination of ringworm?
isolate the animal to 1 room (with non-porous surfaces)
destroy/disinfect bedding
protective clothing
daily vacuuming/disinfectant (sodium hypochlorite - bleach)
what two drugs are used systemically to treat dermatophytosis?
itraconazole
ketoconazole
how is the treatment success of dermatophytosis monitored?
fungal culture every 2 weeks using the Mackenzie test
what is pseudomycetoma also known as?
nodular dermatophytosis
what breed of cats are predisposed to pseudomycetoma?
Persian
what is pseudomycetoma?
subcutaneous form of dermatophytosis that is usually accompanied by typical dermatophyte signs
what should be avoided with cats that have pseudomycetoma?
abdominal surgery as it can introduce disease into the cavity
what is a common parasite that causes spontaneous alopecia?
Demodex mites
what are the common types of Demodex mites?
Demodex canis
Demodex injai
Demodex cati
what animals are effected by canine demodicosis?
young and immunocomprosied dogs
what are the clinical signs of alopecia associated with demodicosis?
alopecia scaling blue-grey hyperpigmentation comedones follicular casts
how can demodicosis be diagnosed?
clinical appearance
skin scrape, hair plucks, biopsy
what are the three main diseases that cause follicular casts?
demodicosis
dermatophytosis
sebaceous adenitis
what should happen when you do a hair pluck for demodex?
demoted should fall off the hair bulb
what should always be done when comedones are present?
skin scrapes
what needs to be identified in adult onset demodicosis?
the underlying disease
what are some underlying disease that may lead to adult onset demodicosis?
hyperadrenocorticism hypothyroidism diabetes mellitus systemic neoplasia immunosuppressive therapy FIV/FeLV
what is used to treat adult onset demdodicosis?
clip long hair and bathe
treat secondary bacterial pyoderma
treat underlying immunosuppression
amitraz and isoxazolines
what is done as a precautionary measure for bitches that have had demodicosis?
spey them - demodicosis often comes back during pregnancy
what is sebaceous adenitis?
an uncommon cause of alopecia that leads to subtle loss of truncal hair that then becomes more generalised
what is dermatomyositis?
rare cause of alopecia resulting in the loss of air from the face and boney prominences
how should a vesicle be biopsies?
cut out the entire vesicle
when sending a suspect tumour biopsy away for analysis, what should it be packaged in? and why?
half in formalin - histopathology
half in sterile saline - tissue culture
what are the three main stages of the hair growth cycle?
anagen
catagen
telogen
what is anagen?
the growing phase of the hair cycle
what is catagen?
the transition phase of the hair cycle with regression if the lower part of the hair follicle
what is telogen?
resting stage of the hair cycle
what is exogen?
the release and shedding of the hair
what is kenogen?
refers to empty hair follicles
what stage of the hair cycle are the majority of follicles in with animals with primary alopecia?
telogen
what can cause hair cycle arrest?
endocrinopathies anagen/telogen deflux paraneoplastic alopecia alopecia X cyclic flank alopecia post-clipping alopecia injection alopecia
what endocrinopathies can cause hair cycle arrest?
hyperadrenocorticism
hypothyroidism
hyperoestrogenism
sex cell alopecias
what are the clinical features of endocrinpathies?
symmetrical to generalised alopecia dull and dry coat comedones hyperpigmentation atrophic skin poor wound healing poor hair growth
why does the coat appear dull and dry with endocrinopathies?
the diseases effect the sebaceous glands
what two effects do glucocorticoids have on the skin?
catabolic and antimitotic
the antimitotic effect of glucocorticoids means there is decreased mitoses of the skin, what does this cause?
thinning
delayed wound healing
pilosebaceous atrophy
what do glucocorticoid inhibit the proliferation/production of at the skin?
fibroblast proliferation
collagen and matrix substance production
what does the inhibition of fibroblast proliferation and collagen/matrix substance production result in?
thinning
fragile vessels
what stages of the hair cycle do glucocorticoid accelerate?
anagen and catagen (meaning all the follicles are in the telogen phase)
what are the typical clinical signs of hyperadrenocorticism?
truncal alopecia comedones skin atrophy and striae prominent blood vessels calcinosis cutis
what are striae?
wrinkles
what is calcinosis cutis?
inorganic, insoluble mineral salts are deposited on the dermis/subcutis
how does calcinosis cutis appear?
crusting and haemorrhage
how does feline hyperadrenocortism compare to canine?
feline is less common but more severe
what is the main clinical sign of feline hyperadrenocorticism?
skin fragility (severe)
what disease is feline hyperadrenocroticism often seen concurrently with?
diabete mellitus
what is the general effect of thyroid hormones on the skin?
stimulate cytoplasmic protein synthesis and increase tissue oxygen consumption
what are the 4 specific effects of thyroid hormones on the skin?
initiate anagen phase and wound healing
decrease cell apoptosis (prolong anagen)
promote matrix cell proliferation
support development of lymphoid tissue, neutrophilic function and lymphocyte funtion
if there hypothyroidism, what happens to the hair cycle?
anagen is not stimulated so majority of hair cells are in telogen (resting)
what are the clinical signs of hypothyroidism?
truncal/extremity alopecia dull hair coat myxoedema weight gain lethargy heat seeking
what does myxoedema cause?
tragic facial expression
what animals is hyperestrogenism most common in?
intact males
why is hyperestrogenism most common in intact males?
due to functional testicular neoplasia - Sertoli cell tumour
what is the effect of oestrogen’s on the hair cycle?
initiate and promote catagen by induction of apoptosis
inhibition of anagen onset - longer telogen phase
what are the clinical signs of Sertoli cell tumours?
testicular masses (not always obvious)
pendulous prepuce
linear preputial erythema
feminisation
how can Sertoli cell tumours usually be cured?
neutering - don’t normally metastasise
what is telogen defluxion?
a sudden loss of hair as the hairs synchronise into telogen
when does telogen deflexion occur?
1-3 months post-stressful event (pregnancy, severe illness, shock, surgery)
what is anagen defluxion?
sudden loss of hair due to damage of the growing hair/follicle
what may cause anagen defluxion?
chemotherapy
severe illness
what are the clinical signs of anagen defluxion?
patchy to complete hair loss (fractured/distorted hair)
loss of whiskers
what are some causes of feline paraneoplastic alopecia?
pancreatic/bile duct carcinomas
neuroendocrine pancreatic tumour
hepatosplenic plasma cell tumour
where do feline paraneoplastic alopecias usually cause hair loss?
ventrum and legs
how does the skin of patients with feline paraneoplastic alopecia appear?
shiny and translucent (not fragile)
what breeds are predisposed to alopecia X?
plush coated - Pomeranians, Chow chows…
what are the clinical signs of alopecia X?
dull dry coat - hair loss in frictional areas
truncal alopecia and hyperpigmentation
dog otherwise well
how does alopecia X progress?
starts with loss of primary hairs (puppy coat) then later there is complete alopecia and hyperpigmentation
how is alopecia X diagnosed?
by exclusion - rule out endocrinopathies, sex hormones and take biopsy
how can alopecia X be treated?
none that is always effective neutering males (deploring implant) melatonin
what word would be used to describe the disease of alopecia X?
cosmetic
with recurrent flank alopecia, where is hairloss mainly seen?
flanks in the thoracolumbar area that can be unilateral
what are the clinical signs of recurrent flank alopecia?
hyper pigmented skin partial to complete alopecia coat colour change flank alopecia dog otherwise well - cosmetic condition
what is recurrent flank alopecia linked to?
reduction in day length, follicular atrophy, dysplasia
what can be used to treat recurrent flank alopecia?
melatonin
what drugs can cause injection site alopecia?
glucocorticoids
vaccines
antibiotics
what are some hair synthesis defects?
congenital alopecia
follicular dysplasias
pattern alopecia
sebaceous adenitis
what are some defects that are associated with congenital alopecia?
adnexal, epidermal, dental and nail defects
what are some breeds that are predisposed to follicular dysplasia?
Irish water spaniel
Portuguese water dogs
airedale
what are the clinical signs of follicular dysplasia?
hair that is present at birth but alopecia develops when the hair starts to cycle
shaft fractures
what breed is bald thigh syndrome seen in?
greyhounds/sighthounds
what are the clinical signs of bald thigh syndrome?
bilateral hair loss on the caudal and lateral thighs (may extend to distal hind legs, ventral abdomen and chest)
when in life is pattern alopecia seen?
later - elderly dogs
where on the body is pattern alopecia usually seen?
pre/post auricular, ventral neck, ventrum, caudal thighs
what breeds can be effected by pattern alopecia?
Yorkshire terrier, dachshund, greyhound, chihuahua
what causes black hair follicular dysplasia?
genetic defects in melanisation causing a defect in pigmentation and hair formation
how does black hair follicular dysplasia progress?
animal born normal but by 4 weeks the black hairs have become dull and may have fractured or been lost
bacterial infection can occur
what causes colour dilution alopecia?
one or more genetic defects in melanisation
what are the clinical signs of colour dilution alopecia?
hair fragility melanin clumping (macromelanosomes) hair fracture/loss scaling possible bacterial folliculitis
how can hair synthesis defects be diagnosed?
history - breed, distribution, coat colour
trichogram
skin biopsy
what can be done to treat hair synthesis defects?
avoid coat damage high quality nutrition gentle anti-scaling shampoos prevent secondary infection sun protection
what is a nodule?
a circumscribed solid elevation greater than 1cm in diameter that usually extends into deep layers of skin
what do nodules usually result from?
infiltration of inflammatory cells, neoplastic cells, deposition of fibrin/crystals
when looking at the clinical presentation of nodules, wha should be described?
location on body number size behaviour clinical features
what are some possible clinical features of nodules?
warm painful hard/soft/elastic/fixed/moveable alopecia ulcerated hyper/hypopigmented
after describing the clinical presentations of nodules, what should be done?
cytology - FNA, apposition
after cytology and histology, what further diagnostic tests can be done on nodules?
immunohistochemistry PCR biochemistry urinalysis serology
what are some examples of foreign bodies that can cause nodules?
plant material
grass awns
embedded insect mouthparts
suture material
what are some endogenous materials that can cause a nodular reaction?
hair, sebum, keratin
calcium salts
tyrosine crystals
what are common causes of abscesses that cause nodules?
penetrating wounds, bites and foreign bodies
what are some examples of filamentous bacteria that cause abscesses?
Actinomyces
Nocardia
Actinobacillus
what are the clinical signs of filamentous bacteria nodules?
ulcerated nodules/abscesses with draining tracts and cellulitis
serosanguineous exudate
possible systemic signs - pyrexia, depression…
how can filamentous bacteria nodules be diagnosed?
cytology (special stains)
histology (special stains)
culture (can take weeks)
how can filamentous bacteria nodules be treated?
surgical drainage and antimicrobial therapy
what are the two main presentations of nodules caused by mycobacteria?
canine leproid granuloma
feline leprosy syndrome
what are the clinical signs of mycobacterial nodules?
single/multiple, firm, well circumscribed nodules in skin/subcutis
how does canine leproid granuloma progress?
self-limiting (usually)
how does feline leprosy syndrome progress?
progressive and occasionally aggressive clinical course
how can mycobacteria nodular diseases be diagnosed?
cytology
histology
PCR
why is culturing of mycobacteria nodular disease not generally carried out?
they are extremely fastidious and generally uncultivatable
how can nodular disease caused by mycobacterium be treated?
long courses (often life long) of antibacterials
what can atypical mycobacterium cause?
granulomatous panniculitis
describe the gross appearance of granulomatous panniculitis
single/multiple nodules, plaques, macule and diffuse swelling
where is granulomatous panniculitis most commonly seen on the animal?
inguinal fat pad
tail base
flank
how can nodular disease caused by atypical mycobacteria be treated?
antibiotic treatment
surgical intervention
what are the clinical signs of nodular mycobacterial disease caused by M. tuberculosis complex?
firm ulcerative nodules
non-healing wounds and draining tracts
tick yellow green fluid
in what animals is nodular mycobacterial disease caused by M. tuberculosis complex most common? where on the body is it seen?
male outdoor cats on the face, extremities, tail base and perineum
how can nodular mycobacterial disease caused by M. tuberculosis complex be diagnosed?
cytology
histology
culture
PCR
how is nodular mycobacterial disease caused by M. tuberculosis complex treated?
notifiable disease - owner may need to be screened for TB
euthanasia often common
multidrug treatment
what are the two types of dermatophyte infections causing nodular lesions?
dermatophytic pseudomycetoma
kerion - nodular dermatophytosis
how does dermatophytic pseudomycetoma present clinically?
a deep dermal/subcutaneous infection painless single/multifocal ulcerated dermal nodules with yellow granular discharge
where on the body is dermatophytic pseudomycetoma most commonly seen?
neck, dorsal, tail flanks and limbs
how can dermatophytic pseudomycetoma be treated?
systemic antifungals such as itraconazole and terbinafine
what animals is dermatophytic pseudomycetoma seen in?
cats - Persians
what animals is nodular dermatophytosis seen in?
dogs
describe the appearance of nodular dermatophytosis
single/multiple erythematous, alopecic, exudative nodules
where on the body is nodular dermatophytosis seen?
head, neck and limbs
how can nodular dermatophytosis be treated?
systemic antifingals - itraconazole and ketoconazole
what can lead to subcutaneous fungal nodules?
traumatic implant of saprophytic organisms on soil and vegetation
what animals is disseminated saprophytic subcutaneous fungal infections seen in?
immunocompromised animals
what is a mycetoma?
pyogranulomatous nodules that contain tissue grains or granules composed of dense colonies of organisms and necrotic debris
what two categories of fungi can cause nodular saprophytic subcutaneous fungal infections?
pigmented
unpigmented
what is chromomycosis?
a subcutaneous and systemic disease associated with pigmented fungal elements (not grain in tissue)
is hyalohyphomycosis a pigmented or unpigmented fungal infection?
unpigmented
where is cryptococcus found and what does it most commonly cause?
in the environment causing systemic mycosis in cats
how can nodular saprophytic subcutaneous fungal infections be treated?
based on culture
systemic antifungals - itraconazole, ketoconazole
amphotericin B
terbinafine
protozoa rarely cause nodular skin lesions, what animals can they cause this in?
immunocompromised
what parasite can cause nodular skin lesions?
Dirofilaria repens
what is the name of the group of nodular causing disorders caused by inflammation?
histiocytic proliferative disorders
what is a histiocyte?
overarching term to describe cells of dendritic cells or macrophage lineage
what are the two types of histiocytic proliferative disorders?
neoplastic
reactive
why does protective clothing need to be worn when dealing with suspected histiocytic proliferative disorders?
they are zoonotic
what are the two types of reactive histiocytic proliferative disorders?
cutaneous histiocytosis
systemic histiocytosis
how does cutaneous histiocytosis appear?
multiple cutaneous and subcutaneous nodules up to 4cm in diameter that are non-painful and non-pruritic
ulcerations common
where on the body does cutaneous histiocytosis usually appear?
face, nose, trunk, extremities
how can histiocytic proliferative disorders be treated?
glucocorticoids
ciclosporin
describe the prognosis for systemic histiocytic proliferative disorders
guarded
are crusts usually a primary or secondary lesion?
secondary
where do crusts originate from?
from drying of exudate, serum, pus, blood and squamous corneocytes
what is scale?
the presence of flakes of keratin in the hair coat and on the skin
what can scale result from?
normal skin function (dandruff) abnormal desquamation abnormal cornification inflammation bacterial and fungal enzymatic action
what are some diseases that can result in primary scale?
primary keratinisation disorders primary seborrhoea zinc responsive dermatosis vitamin A responsive dermatosis ear margin seborrhoea
what are some diseases that can result in secondary scaling?
callus hypothyroidism allergy parasites bacterial infection dermatophytosis sebaceous adenitis
what is done to diagnose a problem when secondary scale seems unlikely?
check parasites
check infection
biopsy
genetic testing
what are some non-specific topical treatments for scale?
keratoplastic/keratolytic products - reduce scale production and remove scale
moisturising and emollient products - hydrate/moisturise the skin
what causes type I zinc-responsive dermatosis?
generally genetically predisposed
what causes type II zinc-responsive dermatosis?
nutritional restrictions seen in young rapidly growing dogs
what are the main presentations of nail disease?
breakages and losses
pus, inflammation, swelling of the nail bed
discolouration
what are some disease that effect the nails?
symmetrical lupoid onychodystrophy
dermatophytosis
acute nail trauma
neoplasia of the ungual fold
what are the clinical sign of symmetrical lupoid onychodystrophy?
nail loss nail breakage/splitting nail pain haemorrhage secondary paronychia multiple nails can be effected
what is onychomadesis?
nail loss
what is onychalgia?
nail pain
what is onychorrhexis?
nail breakage
how does acute nail trauma present?
very painful
what is acute nail trauma a sign of in cats?
RTA (check internal injury)
what are two neoplasias that can occur on the ungual fold?
squamous cell carcinoma
melanoma
what function are anal sacs associated with?
scent marking
where are anal sacs found?
paired sacs between the internal and external anal sphincters
what is a common problems associated with anal sacs?
impaction
what are the clinical signs of impacted anal sacs?
pruritus
pain and depression
malodour
distended sacs
what are some primary causes of anal sac impaction?
thick high volume secretios
change in muscle tone
faecal form - diarrhoea or constipation
plugging of ducts
what are some secondary causes of anal sac impaction?
bacterial infection (possible abscessation)
what are some predisposing factors to impacted anal sacs?
other causes of pruritus (atopic dermatitis, food allergy)
breed
what are some differential diagnoses for anal sac impaction?
anal pruritus - food allergy, atopic dermatitis, vulva fold dermatitis, tail fold dermatitis
abscessation - tumour, anal furunculosis
what are the treatment options for impacted anal sacs?
expression
additional fibre in feed - improve faecal consistency
flush and pack
anal sacculectomy
what tumour can be seen within the anal sac?
anal sac adenocarcinoma
what type of disease is anal furunculosis?
immune mediated skin disease
what breed is predisposed to anal furunculosis?
German shepherds
how can anal furunculosis be treated?
immunosuppressive therapy - prednisolone
food trials
good skin hygiene
surgery
what is the main differential for canine pododermatitis?
sterile pyogranulomatous pododermatitis
what does sterile pyogranulomatous pododermatitis include?
interdigital folliculitis/furunculosis with/without interdigital cysts or nodules
what breeds are predisposed to sterile pyogranulomatous pododermatitis?
smooth, short-coated breeds such as staffies
what can cause sterile pyogranulomatous pododermatitis?
trauma from the environment/self induced - usually on the front feet as they take more weight
describe the pathogenesis of sterile pyogranulomatous pododermatitis
chronic weight bearing and friction on haired skin leads to follicular obstruction, damage and rupture
lesions start sterile and quickly progress to having secondary infection due to rupturing of cysts and self trauma
reoccurrence leads to increased scar tissue and disease perpetuation
where do lesions of sterile pyogranulomatous pododermatitis form?
ventral interdigital surface but then rupture onto the dorsal surface
what type of lesions form with sterile pyogranulomatous pododermatitis?
erythema, oedema, comedones, nodules, pustules, ulcers, haemorrhagic bullae, haemorrhagic draining tracts, pyogranulomas and callus formation
between what digits does sterile pyogranulomatous pododermatitis often effect?
between digits 3 and 4, and 4 and 5
how can sterile pyogranulomatous pododermatitis be diagnosed?
history/clinical exam
consider other differentials and comorbidities - atopic dermatitis, demodicosis
how should sterile pyogranulomatous pododermatitis be treated?
aggressively at the start to prevent scaring immune-modulation topical antiseptics treat secondary infection restrict activity to smooth surfaces protect paw from trauma using boots
