Defense & Barriers 2: Folliculitis Flashcards by Nellie O'Leary

what kinds of lesions can be PRESENT due to folliculitis?

MANY TYPES on the SAME ANIMAL

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TOP 3 DIFFERENTIALS for FOLLICULITIS?

how can we distinguish? (TRICK)

BACTERIAL FOLLICULITIS
DEMODICOSIS
DERMATOPHYTOSIS

we CANNOT distinguish WITHOUT DIAGNOSTICS!

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prior to diagnostics, what 3 things should we gather/do for FOLLICULITIS?

COMPLETE DERMATOLOGIC HX
COMPLETE DERMATOLOGIC EXAM
COMPLETE GENERAL EXAM

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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)

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PREVALENCE of causes of folliculitis in DOGS & CATS?

DOGS = BACTERIAL > DEMODICOSIS > DERMATOPHYTOSIS

CATS = DERMATOPHYTOSIS > BACTERIAL > DEMODICOSIS

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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)

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how long is microsporum canes VIABLE in the environment? what is it?

UP TO 18 MONTHS

DERMATOPHYTE (ringworm, fungi)

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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

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identify disease & genus/species

DERMATOPHYTOSIS (microsporum canis)

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Trichophyton mentagrophyte
what is it?
classification?
found in what animals?

what is it? –> DERMATOPHYTE

classification? –> ZOOPHILIC

found in SMALL MAMMALS & DOGS/CATS

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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

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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

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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

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identify GENUS/SPECIES

MICROSPORA CANIS

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identify GENUS/SPECIES

MICROSPORA GYPSEUM

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identify GENUS/SPECIES

T. MENTAGROPHYTES

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identify GENUS/SPECIES

MICROSPORA GYPSEUM

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identify GENUS/SPECIES

MICROSPORA CANIS

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identify GENUS/SPECIES

T. MENTAGROPHYTES

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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

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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

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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

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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?

1. LIME SULFUR DIP 2. MICONAZOLE + CHLORHEX shampoo

with what & when are we FINISHED with DERMATOPHYTOSIS treatment?

1. 2 NEGATIVE DERMATOPHYTE CULTURES 2. 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?

1. FOLLICULAR CASTS = sebaceous adenitis or demodicosis 2. DRAINING TRACTS if FURUNCULOSIS present 3. Usually NON-PRURITIC unless SECONDARY BACTERIAL FOLLICULITIS PRESENT (this is common and occurs in most cases) SYSTEMIC Dz POSSIBLE!

DIAGNOSIS of demodicosis? (2)

1. DEEP SKIN SCRAPING = need to find AT LEAST 2 mites, ONE NOT ENOUGH 2. 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?

1. SHAR PEIs because CANNOT GET CYTOLOGY 2. LICHENIFIED SKIN 3. 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) 2. S. SCHLEIFERI = SECOND MOST COMMON, DOGS/HUMAN primary reservoir 3. 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