Cutaneous Fungal Disease Flashcards by jared Jensen

lipophilic budding yeasts that are commensals but secondary colonizer in conditions of barrier dysfunctions (atopy, food sensitivity, seborrhea oleosa)

Malassezia Pachydermatis

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How does Malassezia Pachydermatis typically overgrow

secondary to underlying skin disease
-atopy
-food sensitivity
-seborrhea (oleosa)
*no immunosuppression

prefers warm, moist areas, reduced UV light exposure (folded reasons)

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Where are you most likely to find Malassezia Pachydermatis

Skin folds
-prefers warm, moist areas with reduced UV light exposure

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Malassezia Pachydermatis overgrowth is not associated with

immunosupression

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When doing cytology, how do you typically quantify Malassezia Pachydermatis

1+ : some in every field
2+: about 10 in every field
3+ : 30-50 in every field
4+: Malassezia all over the field

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What is the clinical presentation of Malassezia Pachydermatis

erythema, bronze colored greasy exudate (seborrhea oleosa) PRURITUS (inflammatory)

occur: interdigital, claw folds, mucocutaneous junctions, ventral neck, skin folds, ears

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How do you differentiate Malassezia Pachydermatis from porphyrin staining (licking) when it occurs at the claw folds

tape or scrape these
(easier to do from yeast- exudate)
bacterial paronychia possible as well

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How do you diagnose Malassezia Pachydermatis

1) impression smears of moist or waxy surfaces
2) Tape for dry lesions

stain with diff quic

examine under oil immersion, quantify, record
>1-3 yeast/hpf on skin and >5 yeast/hpf in the ear = abnormal

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Some indiviauls with atopy may become _____ to malassezia nad its by products

hypersensitive

even though there is normal or low numbers of yeast it is problematic

if clinical signs consistent any any more than an occasional Malassezia/hpf then treat!

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How do you treat Malassezia Pachydermatis

Topicals*
1) Shampoo
-2% chlorhexidine, 2% miconazole
-2% chlorhexidine, 1% ketoconazole
q2-3 days for 2-4 weeks then once-twice weekly maintenance

2) Wipes: acetic acid, boric acid (Malacetic Wipes, dechra), 2% miconazole, 2% chlorhexidine (Miconahex +Triz, Dechra)
BID for 2-4 weeks then twice weekly for maintenance

3) Sprays or Mousses:
2% miconazole, 2% chlorexidine
BID for 2-4 weeks, then twice weekly for maintenance

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When might you consider systemic treatment for malassezia

-Widespread disease
-Owner unable to perform topical treatment

initial: 2-4 weeks
1) ketoconazole
2) *Terbinafine (pulse therapy) - less likely to have hepatotoxicity
or itraconazole or fluconazole

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What are the three causes of follicultis

1) Bacterial pyoderma
2) Dermatophytosis
3) Demodex

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What is the natural host of Microsporum canis

Cats

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What are 3 common dermatophytosis species

1) Microsporum canis (most common and cats are natural host)
2) Nannizzia gypsea (formerly Microsporum gypseum)
natural habitat in the soil
3) Trichophyton mentagrophytes
Natural host: rodents

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T/F: all dermatophytosis is zoonotic

true

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What is the natural host of Trichophyton mentagrophytes

rodents

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Where is Nannizzia gypsea found

natural habitat: soil

Dermatophtosis is common in _____ and uncommon in _____

common in cats
uncommon in dogs

Microsporum canis

considered the most contagious of the dermatophytosis
cats can be asymptomatic carriers

risk factors: contact (groups)- individuals, fomites
Immunocompromised (young, debilitated)

What lesions are associated with dermatophytes

alopecia
collarettes
scale crust

looks a lot like other dermatologic diseases

What is the most common presentation of dermatophytes in dogs specifically

Fungal Kerion
-Dermatophytic furunculosis
-Face or distal limb
-Focal
-This wont fluoresce
-Any species: M canis, N. gypsea, T. metagrophytes

T/F: Fungal kerions in dogs will fuoresce

False

How many M. canis cases will fluoresce under a wood’s lamp

30-80% of the hair shafts will glow, ignore fibers, crusts, medications, other colors

If it glows, you are not done. Collect these hairs for cytology or culture

If hairs glow under wood's lamp, what should you do to confirm M. canis

collect hairs for cytology/culture Trichogram: use mineral oil, no need for stain, coverslip and look under oil immersion look for spores adhered to hair and for rotten log hairs (no definition)

What is considered the gold standard for dermatophyte diagnosis

DTM culture -difficult to interpret can take 2-4 weeks for diagnosis can speciate

How does the Dermatophyte Test Media for culture work

1) Uses Sabourad's Dextrose Agar (SDA) with phenol red that when dermatophyte eats the protein, the alkaline by-products increase the pH this results in a red color change but it will eventually turn red without dermatophytes 2) Dermatophyte growth must be white or "buff/fuzzy" White/beige growth with color change Check daily, store at room temp, protected from light 3) Can then speciate with Macroconidia (Macroconidia do not grow on the hosts) using a tape cytology from the culture plate

After Dermatophyte culture what is used to speciate

Can then speciate with Macroconidia (Macroconidia do not grow on the hosts) using a tape cytology from the culture plate

Macroconidia do not

do not grow on the host (only on the culture plate)

For dermatophytes, systemic therapy kills ______ topical therapy prevents _____ environmental cleaning prevents _________

Systemics: kills infection Topical: prevents spread Environmental cleaning: prevents reinfection

How long do you treat dermatophytes

until two consecutive negative cultures taken 1-2 weeks apart

What is the dermatophyte treatment triad

Systemic therapy (every postive cat) Topical therapy (every positive case, every exposed case) Environmental cleaning

You need to do systemic treatment for dermatophytes in

every positive cat

How do you systemically treat cats with dermatophytes

Treat every cat 1) Itraconazole - concentrates well in skin/hair, pulse dosing 2) Terbinafine 3) possibly other -azoles but dont build in hair at good levels

What anti-fungal do cats not tolerate

Ketoconazole

What should you do for topical therapy in every animal that is postive and exposed to dermatophytes

Do at least twice weekly 1) Lime sulfur (gold standard) -odor staining, difficult to apply -must let it dry (e-collar) -dont do in bathtub 2) Imidazoles (shampoo)- 10 min contact time -Micronazole -Clotrimazole -Ketoconazole

Why must you let lime sulfur dry with the animal wearing a cone

they will get diarrhea

In dermatophyte cases, what should you do for environmental decontamination

-At least twice weekly, daily is better -Vacuum thoroughly, shampoo carpets with beater brush, Swiffer for hard floors, wood oil soap for wood floors -Wash bedding, clothes 2x on the longest cycle, hot water and bleach is not necessary -Disinfect hard surfaces, remove all hair

What should you do regarding dermatophytes and patient isolation

culture everybody isolate positives to one treatment room (kittens need socialization) gown up get negatives out of there- treat topically if they must stay

What is the most common equine dermatophytes

Trichopyton

What should you do for Equine dermatophytosis

1) topical treatment 2) Twice- weekly bathing -Imidazoles -If suitably focal, could consider ointments/wipes BID spontaneous remission is possible in 1-4 months