Defense & Barriers 2: Folliculitis Flashcards
what kinds of lesions can be PRESENT due to folliculitis?
MANY TYPES on the SAME ANIMAL
TOP 3 DIFFERENTIALS for FOLLICULITIS?
how can we distinguish? (TRICK)
- BACTERIAL FOLLICULITIS
- DEMODICOSIS
- DERMATOPHYTOSIS
we CANNOT distinguish WITHOUT DIAGNOSTICS!
prior to diagnostics, what 3 things should we gather/do for FOLLICULITIS?
- COMPLETE DERMATOLOGIC HX
- COMPLETE DERMATOLOGIC EXAM
- COMPLETE GENERAL EXAM
3 diagnostics to do for folliculitis & what you’re looking for/ruling out?
- SKIN CYTOLOGY –> rule in or out BACTERIAL FOLLICULITIS
- DEEP SKIN SCRAPING –> rule in or out DEMODICOSIS
- TRICHOGRAM –> look at hair shaft for DEMODEX or FUNGI (dermatophytes)
PREVALENCE of causes of folliculitis in DOGS & CATS?
DOGS = BACTERIAL > DEMODICOSIS > DERMATOPHYTOSIS
CATS = DERMATOPHYTOSIS > BACTERIAL > DEMODICOSIS
DERMATOPHYTOSIS?
what is it? (+ what 3 structures it affects)
how are they classified? what are the 3 classes?
zoonotic?
2 methods of transmission? (second has 3 subs)
= FUNGAL infection affecting the keratinized structures of skin (hair, superficial layers and claws)
classification? = based on PREFERRED HOST OR LOCATION
1. Zoophilic = animal is the PREFERRED HOST (microsporum canis)
2. Geophilic = found in the ENVIRONMENT (microsporum gypseum)
3. ANTHROPOPHILIC = HUMANS are the preferred host
YES ZOONOTIC
transmission?
(1) CONTACT with INFECTED HAIRS/NAILS between an INFECTED or ASYMPTOMATIC animal –> MOST COMMON METHOD
(2) CONTACT with ARTHROSPORES SHED INTO ENVIRONMENT from…
1. Dust particles
2. Fomites (grooming supplies, bedding, collars)
3. Ectoparasites (fleas)
how long is microsporum canes VIABLE in the environment? what is it?
UP TO 18 MONTHS
DERMATOPHYTE (ringworm, fungi)
what 4 things predispose an animal to DERMATOPHYTOSIS?
why?
4 things?
1. PRURITUS
2. HUMIDITY
3. GROOMING
4. ECTOPARASITES
due to DISRUPTION OF THE STRATUM CORNEUM, so more likely in ALLERGIC, ITCHY ANIMALS
identify disease & genus/species
DERMATOPHYTOSIS (microsporum canis)
Trichophyton mentagrophyte
what is it?
classification?
found in what animals?
what is it? –> DERMATOPHYTE
classification? –> ZOOPHILIC
found in SMALL MAMMALS & DOGS/CATS
DERMATOPHYTOSIS in CATS…
5 clinical signs to remember?
4 lesion distributions?
clinical signs?
1. erythema
2. comedones
3. hyperpigmentation
4. ABNORMAL NAIL GROWTH
5. VARIABLE PRURITUS
lesions?
1. Face
2. Ears/pinna
3. Muzzle
4. Around eyes
4 other things that can cause wood’s lamp fluorescence?
what SHOULD we pluck for fungal culture/trichogram?
- DETERGENT RESIDUE
- CRUSTS
- SCALE
- MEDICATIONS
only pluck hairs that FLUORESCE APPLE GREEN
FUNGAL CULTURE…
2 methods? (one for first, three for second & why FALSE NEGATIVES are common)
what media is used?
HOW does the media change color for DERMATOPHYTES vs SAPROPHYTES?
false positive risk for CULTURE?
2 methods?
1. toothbrush
–> BRUSH COAT for 2-3 minutes with TOOTHBRUSH (~20 strokes)
–> Spores will LIVE UP TO 18 MONTHS so CAN KEEP
- hair plucking
–> Pluck hairs/crusts from edges of suspect lesions
–> Pluck hairs that FLUORESCE with wood’s lamp
–> PLUCK AS MANY HAIRS AS YOU CAN because there’s high chance of FALSE NEGATIVE
what media is used?
–> Dermatophyte Test Media = Saboraud’s Dextrose Agar (SDA)
HOW does the media change color = Dermatophytes will INITIALLY UTILIZE PROTEIN –> creates ALKALINE ENVIRONMENT –> RED COLOR
dermatophytes vs. saprophytes?
1. DERMATOPHYTES use protein FIRST
–> Change usually occurs within 7 days
2. SAPPROPHYTES USE CARBS FIRST and PROTEINS LATER
–> Change usually occurs 10-14 DAYS LATER
**CAN READ FALSE POSITIVES IF ONLY BASING ON COLOR CHANGE
identify GENUS/SPECIES
MICROSPORA CANIS
identify GENUS/SPECIES
MICROSPORA GYPSEUM
identify GENUS/SPECIES
T. MENTAGROPHYTES
identify GENUS/SPECIES
MICROSPORA GYPSEUM
identify GENUS/SPECIES
MICROSPORA CANIS
identify GENUS/SPECIES
T. MENTAGROPHYTES
DERMATOPHYTE PCR…
= what does it test for? what clinically does this mean?
3 things that could cause POSITIVE result?
3 things that could cause NEGATIVE result?
timing for PCR vs. fungal culture?
= TESTS FOR PRESENCE OF DNA, so NOT helpful for determining response to treatment
POSITIVE result due to…
1. ACTIVE infection
2. FOMITE carriage
3. DEAD FUNGAL ORGANISMS from a treated patient
NEGATIVE result due to…
1. POOR SAMPLING technique
2. Successful cure
3. No infection in the first place
**FUNGAL CULTURES TAKE 4 WEEKS TO CONFIRM, PCR ONLY 1 WEEK
HISTOPATHOLOGY & DERMATOPHYTOSIS
what will it do for dermatophytes?
often needs these 2 things to visualize?
what 3 clinical presentations would indicate this?
MAY or MAY NOT help identify dermatophytes!
needs…
1. SPECIAL STAINS
2. H&E
clinical presentations?
1. NON-HEALING (indolent) wound or nodule
2. CHRONIC facial lesions that RESEMBLE PEMPHIGUS
3. Lesions of UNKNOWN CAUSE
TREATMENT for dermatophytosis…
RECOMMENDED protocol?
when can we stop treatment?
which medication is ALWAYS required?
protocol?
= Some pets will SELF-CURE, but since zoonotic potential, treatment RECOMMENDED FOR ALL INFECTED ANIMALS with COMBO SYSTEMIC & TOPICAL
stop treatment?
= MUST CONTINUE TREATMENT UNTIL OBTAINING 2 NEGATIVE DERMATOPHYTE CULTURES
**TOPICAL TREATMENT ALWAYS REQUIRED
SYSTEMIC therapies for DERMATOPHYTOSIS…
AZOLES? (2)
include one that’s good for dogs/bad for cats, compounding, pulse-dosing, side effects, mechanism of action
ALLYLAMINES? (1)
method of action?
3 side effects?
(1) AZOLES
1. IMIDAZOLES (ketoconazole)
**AVOID KETOCONAZOLE IN CATS (hepatotoxicity)
–> In dogs, COMMONLY USED with rare S/E
- TRIAZOLES (itraconazole)
–> Requires a SPECIAL FORMULATION for absorption through GI tract
–> ONLY USE BRAND-NAME because COMPOUNDED has VARIABLE BIOAVAILABILITY
–> Can be given PULSE dosing (week on week off) because it’s LIPOPHILIC & ACCUMULATES in the EPIDERMIS & SEBACEOUS GLANDS
Side effects?
–> In both cats/dogs, ANOREXIA common but usually well-tolerated
Mechanism of action?
= INHIBITS LANOSTEROL 14-ALPHA DEMETHYLASE, which is a FUNGAL P450 ENZYME and converts LANOSTEROL –> ERGOSTEROL
–> Ergosterol needed for FUNGAL MEMBRANE INTEGRITY, so its depletion = FUNGISTATIC EFFECTS
(2) ALLYLAMINES (TERBINAFINE)
Method of action?
= inhibits SQUALENE EPOXIDASE to INHIBIT ERGOSTEROL SYNTHESIS
Side effects?
1. ELEVATED LIVER ENZYMES
2. Soft stool/D+
3. INTENSE FACIAL PRURITUS (rare in cats)
2 most effective SYSTEMIC TREATMENT OPTIONS FOR DERMATOPHYTOSIS?
- TRIAZOLES (ITRACONAZOLE)
- ALLYLALMINE (TERBINAFINE)
what determines the TOXICITY of azoles?
depends on drug’s AFFINITY for MAMMALIAN P-450 ENZYME SYSTEMS
LIME SULFUR DIP…
good choice for what organism?
safe for…
formulation? (1)
application? (rinsing, how often to apply?)
side effect? (1)
DERMATOPHYTES
Safe to use in ALL AGES CATS/DOGS
formulation?
= Available in concentrated form, but needs DILUTE 4 OZ/GALLON OF WATER
application?
1. **DO NOT RINSE AFTER APPLICATION
2. Recommended 1-2X/week
side effect?
1. Can irritate mucous membranes, so keep pets in E-collar until dry
how many times per week and for how long should bathing be done for DERMATOPHYTOSIS?
2X per week for AT LEAST 10 MINUTES
2 topical options for dermatophytosis?
- LIME SULFUR DIP
- MICONAZOLE + CHLORHEX shampoo
with what & when are we FINISHED with DERMATOPHYTOSIS treatment?
- 2 NEGATIVE DERMATOPHYTE CULTURES
- Do first culture 3-4 weeks after starting therapy, then every 2-4 weeks after
environmental decontamination for DERMATOPHYTOSIS?
how does dermatophytosis exist in environment?
how long can it stay in environment?
why is it dangerous?
what is the MOST important part of the clean?
Infective spores are SHED INTO THE ENVIRONMENT WITHIN INFECTED HAIRS
REMAIN FOR UP TO 18 MONTHS
Hairs can be source of RE-INFECTION
**THEREFORE, THE MOST IMPORTANT PART IS THE HARD CLEAN OF HAIRS/DEBRIS
RARE presentations of dermatophytosis…
2 types?
3 clinical signs?
WHAT SPECIES/BREEDS?
= PSEUDOMYCETOMAS & MYCETOMAS
1. SQ infections
2. Nodules w/ draining tracts
3. Exudate often has tissue grains
YORKIES & PERSIANS
identify DISEASE & UNIQUE PRESENTATION
DERMATOPHYTOSIS
**PSEUDOMYCETOMAS & MYCETOMAS
identify GENUS/SPECIES
where does it live?
DEMODEX CANIS
HAIR FOLLICLES
identify GENUS/SPECIES
body description?
where does it live?
what breeds?
DEMODEX INJAI
LONG-BODIED MITE
lives in FOLLICLES, SEBACEOUS GLANDS/DUCTS
in TERRIERS
identify GENUS/SPECIES
body description?
variation of…
DEMODEX CORNEI
SHORT-BODIED MITE
variation of CANIS
DEMODICOSIS…
3 species?
classification? (+3 age markers)
DEMODEX INJAI, CORNEI and CANIS
classification = JUVENILE-onset or ADULT-onset possible!
1. Juvenile = DOGS LESS THAN 2 YEARS
2. Adult = DOGS OVER 4 YEARS
3. Dogs between 2 and 4 years may have CHRONIC UNDIAGNOSED DISEASE
identify disease
JUVENILE DEMODICOSIS
JUVENILE DEMODICOSIS…
what age?
what breeds?
why does it develop?
should we breed affected dogs?
IN DOGS LESS THAN 2 YEARS
More common in BULLY-TYPE breeds
May develop BECAUSE OF AN ABNORMALITY IN T-CELL FUNCTION
HERITABLE, DO NOT BREED
LOCALIZED demodicosis
in what age dogs?
lesion number/outcome?
generally, treatment..?
when IS treatment necessary?
what treatment would you give/when would you recheck?
IN YOUNG DOGS ONLY
IF LESS THAN 4 LESIONS = IT’LL SELF CLEAR
Treatment GENERALLY NOT NEEDED as most will RESOLVE ON THEIR OWN within 1-2 months
If progress to GENERALIZED TREATMENT RECOMMENDED
Can consider TOPICAL TREATMENT WITH ANTIMICROBIAL activity
–> Recheck in 1 month
GENERALIZED demodicosis…
how many lesions/how much of body affected?
what specific area tends to be affected?
how long are the lesions present?
> 4 LESIONS or an ENTIRE BODY REGION AFFECTED
Some say it’s if the FEET are affected
LESIONS PRESENT FOR >6 MOS
identify DISEASE
DEMODICOSIS
identify DISEASE
DEMODICOSIS
identify DISEASE
DEMODICOSIS
4 unique clinical signs of DEMODICOSIS?
can SYSTEMIC illness occur?
- FOLLICULAR CASTS = sebaceous adenitis or demodicosis
- DRAINING TRACTS if FURUNCULOSIS present
- Usually NON-PRURITIC unless SECONDARY BACTERIAL FOLLICULITIS PRESENT (this is common and occurs in most cases)
SYSTEMIC Dz POSSIBLE!
DIAGNOSIS of demodicosis? (2)
- DEEP SKIN SCRAPING = need to find AT LEAST 2 mites, ONE NOT ENOUGH
- TRICHOGRAM = for when we can’t scrape, like around eyes and face, less sensitive
identify DISEASE
DEMODICOSIS
what 3 situations would a BIOPSY be indicated for DEMODICOSIS diagnosis?
- SHAR PEIs because CANNOT GET CYTOLOGY
- LICHENIFIED SKIN
- PODODERMATITIS
identify DISEASE
DEMODICOSIS
identify GENUS/SPECIES
in what species?
what kind of mite?
body?
DEMODEX GATOI
CAT
FOLLICULAR mite
LONG-BODIED
identify GENUS/SPECIES
where does mite reside?
body?
causes WHAT clinical sign?
contagion?
most often associated with WHAT clinical presentation? what 4 kinds are there?
2 treatment options? (topical & oral)
DEMODEX CATI
SUPERFICIAL MITE
SHORT-BODIED
causes SEVERE PRURITUS
CONTAGIOUS AS HECK
Most often associated with IMMUNOSUPPRESSION…
1. Corticosteroid administration
2. FeLV/FIV
3. Diabetes
4. NEOPLASIA
topical?
1. SELAMECTIN/SAROLANER or FLURALANER TOPICAL
2. ORAL LOTILANER
identify GENUS/SPECIES
DEMODEX CATI
PYODERMA…
= definition
usually caused by WHAT?
what 4 things usually cause SECONDARY pyoderma?
= any PYOGENIC inflammation in the skin
usually caused by BACTERIAL (staph) infection
secondary pyoderma?
1. Allergic skin diseases
2. Endocrinopathies
3. Immunosuppression
4. Ectoparasites
STAPHYLOCOCCUS…
is a ____ resident of the ____ and ____ ____ in ____ and ____
coagulase POSITIVE staph? (3, including PRIMARY reservoirs & which are MOST COMMON)
coagulase NEGATIVE staph? (how many species? 2 traits?)
NORMAL, SKIN, MUCOUS MEMBRANES, MAMMALS, BIRDS
coagulase POSITIVE staph?
1. S. PSEUDINTERMEDIUS = MOST COMMON, DOGS are primary reservoir (cats & herbivores included)
- S. SCHLEIFERI = SECOND MOST COMMON, DOGS/HUMAN primary reservoir
- S. AUREUS = HUMANS primary reservoir
coagulase NEGATIVE staph?
> 45 species!
usually COMMENSAL/TRANSIENT
taking a CULTURE for staph from CONTENTS of pustule vs. crust/epidermal collarette?
If a culture is from CONTENTS of a pustule in ASEPTIC MANNER, then MORE LIKELY TO BE TRUE DIAGNOSIS/PATHOGENICITY than crust/epidermal collarette, which contains contaminants
