Dermatology 2 Flashcards
what are the 3 types of pyoderma ?
surface, superficial and deep
which pyoderma effects the surface of the skin? what are some examples?
- surface pyoderma
- examples are: hot spot, intertrigo
which pyoderma effect the epidermal layer and/or hair follicles ?
superficial pyoderma
which pyoderma effects the dermal layer plus follicles? what are some examples?
- deep pyoderma
- exudation of blood or pus, crusting, odor, ulceration, fistula and swelling
how do we diagnose pyoderma?
- clinical signs like pustules, papules, crusts, etc.
- cytology
- culture
should we do cytology and culture on surface pyoderma?
cytology - yes, critical
culture - no, not really helpful, spend $ on something else
should we do cytology and culture on superficial pyoderma?
yes and no
- cytology can be supportive
- culture can sometimes help
should we do cytology and culture on deep pyoderma?
cytology - often negative
culture - yes, always culture!
when should we absolutely do a bacterial culture for pyoderma?
- if less than 50% improvement or new lesions after 2 weeks of treatment
- residual lesions at 6 weeks
- intracellular rods on cytology
- history of MRSA
what should we culture for pyoderma?
the pustules are best but can also culture under crusts or the epidermal collarettes
what type of pyoderma do we use topical antibacterial agents to treat?
- surface pyoderma
- mild or localized pyoderma
- can be helpful for deep pyoderma
what type of pyoderma do we use systemic antibiotics to treat?
- superficial pyoderma
- deep pyoderma
- rarely surface pyoderma
true or false.
Topical therapy may eliminate the need for systemic antibiotics.
true
true or false.
Topical antibacterial therapy is only helpful for certain types of pyoderma.
false, helpful in all pyodermas
what are some examples of topical antibacterial agents ?
benzoyl peroxide, chlorhexidine, iodine, gentamycin, polymyxin b, bacitracin
- mupirocin and silver sulfadiazine
which has follicular flushing capabilities, benzoyl peroxide or chlorhexidine ?
benzoyl peroxide
would you use chlorhexidine or benzoyl peroxide for a pyoderma with oily seborrhea?
benzoyl peroxide, because it has a degreasing agent
what type of bacteria is mupirocin effective against?
gram positive bacteria including MRSA
what is silver sulfadiazine effective against?
several types of bacteria including psuedomonas
what are the first tier systemic antibiotics we use for pyoderma?
- 1st generation cephalosporins (ex. cephalexin)
- amoxicillin/clavulanic acid
- clindamycin
what are the second tier systemic antibiotics we use for pyoderma?
- empirically: sulfas, erythromycin, doxycycline
- based on c/s results: chloramphenicol, rifampin or amikacin
what are the 3rd tier systemic antibiotics we use for pyoderma?
fluoroquinolones and THIRD generation cephalosporins
- based on results from a c/s
when do we use 3rd tier systemic antibiotics for pyoderma?
as a LAST RESORT
examples of a 3rd generation cephalosporin?
enrofloxacin, marbofloxacin, ciprofloxacin, cefovecin (convenia), cefpodoxime (simplicef)
how long should we treat superficial pyoderma for?
treat 3-4 weeks minimally and treat 1 week beyond resolution
how long should we treat deep pyoderma for?
treat 3-12 weeks and treat 2 weeks beyond resolution
what are some reasons for recurrent pyodermas?
- not treating appropriately
- an underlying reason like immunosuppression, corticosteroid use, endocrine disease, or allergies
what type of pyoderma is an acute traumatic pyodermatitis (HOT SPOT)?
SURFACE pyoderma
what type of pyoderma is puppy pyoderma (IMPETIGO) ?
SUPERFICIAL pyoderma
what type of pyoderma is nasal folliculitis/furunculosis?
superficial AND deep pyoderma
what type of pyoderma is chin acne?
DEEP pyoderma
what type of pyoderma is a lick granuloma (acral lick dermatitis) ?
DEEP pyoderma
true or false.
acute moist dermatitis is a lick granuloma.
false, it is a hot spot or pyotraumatic dermatitis
where do we commonly see hot spots ?
hip/thigh and ear
what is the cause of hot spots?
self induced trauma
do we treat pyotraumatic dermatitis with steroids?
we can, hot spots are an exception where we can use corticosteroids to break the itch cycle
what do you see with impetigo (puppy pyoderma)?
pustular rash in axillary or inguinal areas
how do we treat impetigo ?
its usually self-limiting, can use topical antibacterial shampoos and occasionally may need systemic antibiotics
what happens to cause nasal folliculitis and furunculosis?
the hair follicle has bacteria growing in it, usually staph
true or false.
nasal folliculitis usually has an underlying cause
true but not always
what age do we commonly see chin acne in ?
young dogs < 1 year
what do we use to treat chin acne?
topical benzoyl peroxide in mild cases, can add systemic antibiotics if a severe case
what can cause a lick granuloma?
- primary factors can be: atopy, food allergy or trauma which causes them to start licking
- perpetuating factors that can keep the lick cycle going are: deep pyoderma, ruptured hair follicle, compulsive behavior
how can we treat lick granuloma ?
treat the underlying cause as well as stop what is keeping the lick cycle going - break the itch-lick cycle
where do we commonly see Malassezia dermatitis?
ears, lip folds, ventral neck, axilla, interdigital and perianal
check the ears and folds
is Malassezia frequently a primary invader of skin and ears?
no, SECONDARY invader
what are some clinical signs of Malassezia?
- pruritus
- malodor
- erythema
- greasy scaly plaques
- otitis externa
- paronychia - infection of nails
what clinical signs do we see with CHRONIC malassezia ?
lichenification, HYPERpigmentation and hyperkeratosis
how do we diagnose malassezia ?
- history of pruritus
- clinical signs (can look like allergic dermatitis)
- cytology - ESSENTIAL
how do we treat malassezia?
- anti-yeast shampoos: ketoconazole, miconazole, etc. (2-3x weekly)
- creams and lotions
- systemic ketoconazole or itraconazole
Also treat any underlying cause
do we prefer to treat malassezia topically or systemically?
always use topical if possible, reserve systemics for extensive infection or if topical isn’t working
how does feline pruritus differ from canine pruritus?
- skin lesions are different
- excoriation, lichenificiation and hyperpigmentation are rare
what is the first thing we should do when we see skin signs in a cat?
eliminate ringworm and fleas as ddx
what are the 3 forms of skin lesions we see with pruritus in cats?
- bilaterally symmetrical hair loss with normal (non-inflammatory) skin
- miliary dermatitis
- eosinophilic granuloma complex
how can we determine whether feline symmetrical alopecia was self-induced or not?
a trichogram
what is a cause of self-induced feline symmetrical alopecia ?
psychogenic caused by anxiety or pruritic conditions
where do we usually see signs from psychogenic alopecia?
areas that are easiest to reach like medial thighs, ventral abdomen and medial forelegs
how can we tell if a cat has a flea allergy vs another pruritic condition?
will see caudo-dorsal alopecia but can have facial, limb and neck involvement. Will also have eosinophillic granuloma complex lesions too
how can we tell if a cat has atopy vs another pruritic condition?
will see barbering of the ventrum and medial front limbs
how can we tell if a cat has food allergies vs another pruritic condition?
will see persistent and year-round pruritus at any site on the body, especially face and head
what is responsible for feline scabies?
notoedres
what part of the body is affected with feline scabies?
pinna, face, neck, forelimbs then whole body
how do we treat feline scabies ?
lime sulfur dips or ivermectin injections
can also use selamectin or moxidectin
what type of demodex affects cats?
demodex gatoi
what cause of pruritus in cats has a “salt and pepper” appearance?
fur mite - lynxacarus
how do we diagnose lynxacarus?
acetate tape or trichogram
true or false.
Pyoderma is never seen in cats
false, it is RARELY seen in cats
what can be a cause of non self-induced alopecia in cats?
- endocrine disease
- paraneoplastic syndromes
what can cause “skin fragility” in an alopecia cat ?
HYPER adrenocorticism
what can give a shiny appearance to the skin in an alopecia cat?
pancreatic neoplasia which causes a paraneoplastic syndrome
what clinical signs do we see in cats with miliary dermatitis?
crusted papules, erythema and secondary alopecia
what are the 3 presentations of eosinophilic granuloma complex?
- indolent ulcers
- eosinophilic plaque
- collagenolytic/eosinophilic granuloma
how to we confirm the lesion is part of the eosinophilic complex?
cytology will show eosinophils, can biopsy and culture as well
what is the cornerstone of therapy with eosinophilic granuloma complex?
identifying and managing the underlying cause
do we treat eosinophilic granuloma complex in cats with topicals or systemic drugs?
- topicals not ideal because cats can lick off
- systemic glucocorticoids are main stay of tx
- can use antibiotics for secondary bacterial infections
if you have a dog with patchy, focal (“moth eaten”) alopecia, what is likely the cause?
pyoderma or an infection
if you have a dog with diffuse, bilaterally symmetrical alopecia, what is the likely cause?
endocrine or follicular dysplasia
when evaluating a dog with alopecia, what are important things to know?
- age of onset and breed
- pruritic vs non-pruritic
what is folliculitis and what are some causes ?
- inflammation of the follicle wall
- demodex, dermatophytes and pyoderma
what is furunculosis?
rupture of deeply infected hair follicle within the dermis
what is injection site alopecia and how does an animal acquire it?
- hair loss at injection site or in a distant location
- idiosyncratic immunological rxn with rabies and lepto vaccines
who is the reservoir for microsporum canis?
CATS NOT DOGS
what kind of animal is ringworm (dermatophtosis) more likely to effect?
young cats
what happens when a cat is exposed to ring worm that causes alopecia ?
invades anagen hairs/skin
how do we diagnose ringworm?
fungal culture (DTM culture) mostly but can use woods lamp too (not always accurate)
what is an important point to remember about the DTM culture for ringworm?
we have to watch it everyday because the color change happens at the same time there is growth
true or false.
most healthy animals will self-cure if they have ringworm
true
if healthy animals can self cure, why do we treat them?
to minimize possibility of zoonosis and environmental contamination
what is the treatment for dermatophytosis?
- environmental decontamination
- topical treatments (lime sulfur dips, Rx shampoo)
- systemic drugs (itroconazole, ketoconazole, NOT fluconazole - can cross BBB)
how long do we treat for dermatophytosis?
we treat until there’s 1 or more negative fungal cultures
if using systemic treatment should treat until 2 negative cultures 1 month apart
what is the systemic drug of choice for ring worm?
itraconazole
what is the pathogenesis of demodex with juvenile onset?
- depressed T cell function
- decreased Th1 response
- mite-specific immuno-incompetence
what is the pathogenesis of demodex with adult onset?
immunosuppression (can be from drugs, concurrent disease, endocrine diseases or idiopathic)
how do we diagnose demodex?
- deep skin scrapes
- trichogram
- biopsy if indicated
true or false.
most cases of generalized demodicosis that occur at 2-4 years of age were likely undiagnosed juvenile-onset demodicosis
true
do we usually treat localized demodex?
no, 90% usually resolves but if secondary pyoderma is present we treat that
true or false.
we treat localized demodex with glucocorticoids.
FALSE DO NOT USE GLUCOCORTICOIDS
how do we treat generalized demodex ? what is the average duration of treatment?
usually daily ivermectin or weekly mitoban dips, average duration of treatment is about 3 months but can take 6 + months in some cases
caution using ivermectin with collies - MDR gene mutation
true of false.
we never use glucocorticosteroids with generalized demodex.
True, NEVER use them
does spontaneous remission of generalized demodex happen in up to 70% of young dogs?
NO, up to 50% of cases
true or false.
you should neuter a dog with generalized demodex.
true, neuter dog after infection is controlled
what is sebaceous adenitis?
inflammation and destruction of sebaceous glands, we don’t know the cause
what are some important clinical signs of sebaceous adenitis?
- long coated dogs: follicular casts
- short coated dogs: moth-eaten appearance
how do we diagnose sebaceous adenitis?
skin biopsy from the dorsal surfaces
how do we treat sebaceous adenitis ?
first choice - topical shampoos, topical sprays
second choice - systemic drugs
when do we use second choice treatment for sebaceous adenitis?
when there is a biopsy or if first line treatment doesn’t work
what breeds do we see familial dermatomyositis in?
collie and sheltie breeds
what is the time line of clinical signs with familial dermatomyositis?
- skin lesions at 2-6 months of age
- muscle atrophy at 3-5 months of age
is alopecia of endocrine diseases pruritic?
NO
what causes calcinosis cutis?
hyperadreoncoricism
what is the most common underlying cause of demodicosis?
CUSHINGS DISEASE
what disease looks just like an endocrine disease but has normal endocrine tests?
- alopecia X
- pattern baldness
- recurrent flank alopecia
what is the difference between alopecia X and endocrine diseases ?
- hair loss starts earlier (around 3 years old)
- no systemic signs
what breed has thinning hair coat on the ears ?
dachshund
how can we definitively diagnose color dilution alopecia?
biopsy hair for abnormal hairshafts and distorted hair follicles full of keratin and melanin
do we need a biopsy to confirm follicular dysplasia ?
yes
what is recurrent flank alopecia and where does it effect ?
- seasonal follicular dysplasia
- flank and mid-lateral thorax
- can be uni or bi-lateral
how long can alopecia persist with post clipping alopecia?
12-24 months
