Pruritus 4- Inections Flashcards
What are the surface pyodermas?
Pyotraumatic pyoderma (hot spot)
Intertrigo (skin fold rash)
Mucocutaneous pyoderma
Bacterial overgrowth
That are the superficial pyodermas?
Impetigo
Superficial bacterial folliculitis
Superficial spreading pyoderma
What are the deep pyodermas?
Folliculitis/furunculosis Lick granuloma Muzzle pyoderma Pedal pyoderma Cellulitis Pyotraumatic syndrome folliculitis/furunculosis
What type of bacteria is usually found in surface vs superficial vs deep pyodermas?
Surface - mixed population
Superficial — staphylococcus
Deep — mostly staph but can be mixed
Clinical signs with pyoderma?
Pustules
Papules
Crust
When are bacterial cultures for pyodermas mandatory?
If <50% improvement within 2wks of treatment
New lesions after 2wks of treatment
Residual lesions at 6wks
Intracellular rods on cytology
Hx of MRSP and MRSA
What lesions are best for culture?
Pustules
Under crusts
Epidermal collarettes
What is the purpose of topical therapies for dermatitis?
Decrease duration of systemic Ab or may eliminate need for systemic Abs
Prophylactical use for recurrent pyodermas
Little to no side effects
How does Benzyol peroxide compare to chlorhexidine?
Benzoyl peroxide
- 1-5% antimicrobial
- more drying
- follicular flushing activity
- keratolytic
- degreasing agent
Chlorhexidine
- <0.5% antimicrobial
- less drying
- no follicular flushing activity
How often should you apply topical shampoo for pyoderma?
2-3x a week
What is mupirocin and what is it used for?
Topical bacterial static at low concentrations and bacteriocidal at high concentrations
Gram positive bacteria including MRSA
What is silver sulfadiazine and what is it used for?
Topical antibacterial
Burns, wounds, ear infections
Particularly effective against pseudomonas
What are your first tier antibiotics uses for pyoderma?
1st generation cephalosporins (eg cephalexin
Amoxicillin/clavulanic acid
Clindamycin
What 2nd tier antibiotics can you used empirically against pyoderma?
Sulfadiazine
Erythromycin
Linomycin
Doxycycline
—> chloramphenicol, rifampin, and amikacin should only be used based on C/S results
What are your LAST resort antibiotics for treating pyoderma?
Fluoroquinolones —> batryil = enrofloxacin —> zenoquin = marbofloxacin —> cipro = ciprofloxacin —> orbax = orbifolxacin
3rd gen cephalosporins
—> convenia = cefovecin
—> simplicef = cefpodoximine
How long do you treat a superficial pyoderma?
3-4weeks minimum
1 week beyond resolution
Exam every two weeks
How long do you treat a deep pyoderma?
3-12weeks
2 weeks beyond clinical resolution
Mucocutaneous swelling, erythema, crusting
Affecting lips symmetrically, commisures affected
Painful pruritic, fissures, depigmented
Dx?
Mucocutaneous pyoderma
Treatment of mucocutaneous pyoderma?
Clip ad clean area
Mupirocin
Systemic ABs?
What is the pathogenesis of pyotraumatic dermatitis?
Induced by the patient —> self trauma
Secondary to underlying dermatitis (eg flea allergy)
Intense trauma in short time
Red, most, exudative, crusting
Denuded due to self trauma
Dx?
Pyotraumatic dermatitis
What is the treatment for pyotraumatic dermatitis?
Antibiotic/steroid
Short term course corticosteroids
Predisposing causes?
Young dog with vesicles/pustules and non-follicular pustules in the ventral areas of the body
Dx?
Impetigo
What are causes of impetigo?
Staphylococcus Poor husbandry ( poor hygiene, nutrition, internal parasites)
Treatment for impetigo?
Antibacterial shampoo
- chlorhexidine
- benzyol peroxide
Topical antibiotic washes/creams
- chlorhexidine
- mupirocin
- fucidin
Causes of superficial pyoderma in dogs?
Staphylococcus pseudintermediums - confined to hair follicle
Underlying causes
- > bacterial
- > dermatophytes
- > demodex
Tiny pustules in with hairshaft protruding from center
Follicular papule
Patchy focal alopecia
Epidermal collerettes
Scaling-seborrhea
Hyperpigmentation/excoriation
Dx
Superficial pyoderma
How do you diagnose superficial pyoderma?
Lesions
Skin scrape, plucks, cytology
Woods lamp and hair pluck cultures (dermatophytosis)
Cytology - degenerative neutrophils, phagocytosed cocci, proteinaceous background
What is the treatment for superficial pyoderma?
Antibiotics 21-28days (1 week past resolution)
Antibacterial shampoo
- chlorhexidine
- ethyl lactate
- benzyol peroxide
T/F: if you have a deep pyoderma, you should always look for an underlying disorder
True
What is the pathogenesis of deep pyodermas?
Bacterial adhesions -> increased in allergic conditions, humidity, metabolic disease, or in high bacterial numbers
Bacteria can produce toxins —> induce necrosis/ antigens
Predisposing causes to deep pyodermas
Compromised skin defense - Strep pseudintermedius is the most important pathogen
—> allergy
—> seborrhea
—> follicular pathology
—> hyperadrenocortisim or hypothyroidism
—> primary immunodeficiency (rare)
—> secondary immunodeficiency - ehrlichia, distemper, retrovirus
Breeds predisposed to deep pyoderma
GSD and Bull terriers
What do you usually see on a GSD with a deep pyoderma
Pustule, ulcer, and fistula
Rump and thoracic wall regions
Skin blackens and becomes thin
Pain and pruritus
What do you normally see in a bull terrier will deep pyoderma?
Hocks, elbow, ventral abdomen, pododermatitis
UV light trauma may predispose skin to infection/SCC
Associated feet and usually painful
T/F: feline pyoderma is very rare
True
—check affected cats for retroviruses
How would you diagnose deep pyoderma?
Cytology
—> pyogranulomatous exudate
—> cocci found
Histopathology
—> biopsy- infection may mask underlying dz
—> allergy - flea, food, atopy
—> endocrinopathies
How do you treat deep pyoderma?
Topical
- > shampoo and rinses (massage and leave in for 15mins, every 3-7days)
- > hydrotherapy removes cysts
- > steroid -antibiotic combinations
Systemic antibiotics
- > B-lactamase resistant penicillins
- > multiple cultures : treat strep first
- > high dosage for bioavailability to skin , long treatment (6-8weeks or 2 weeks past resolution )
Immunomodulation (adjunct therapy)
-cimetidine and levamisole
Subcuteous abscess
Draining tracts
Exudate is thick, yellow-grey, hemorrhagic and fowl smelling
DDX?
Actinomyocisis or nocardosis
In what dogs do you most commonly see actinomyosis?
Hunting gos
Infection following trauma, penetrating wounds
How can you confirm diagnosis of actinomycetes/nocardia and how would you treat?
Diagnosis
- anaerobic culture
- histopathology with special stains —> sulfur granules
- cyology
RX
-surgical debulking
-long term antibiotics
Actinomycosis -> penicillin G, erythromycin, clindamycin
Nocardisois -> TMS, ampicillin, erythromycin, minocyline
Subcuteanous nodules that slowly developed over months
Non healing abscess, cellulitis, ulcer, fistula
Regional lymph nodes are enlarged
Drain -> sero-anguneous/purulent exudate
Ddx
Mycobacterium
Cancerous (SSC?)
Treatment for mycobacterium ?
Wide surgical excision
Long term AB —> clarithromycin, enrofloxacin, doxycycline
Moist, malodorous, macerated, pruritic skin within facial folds of a bulldog?
Dx?
Intertrigo
Skin fold pyoderma
Treatment for intertrigo?
Topical hygiene —> shampoo, rinse, topical antibiotic
Occasionally systemic antibiotics
Species of yeast affecting dogs ?
Malassezia pachydermatitis
Species of yeast affecting cats?
Malassezia sympodialis and globose
Where is Malassezia usually found?
Ear Lip folds Ventral neck Axillary Interdigital Perianal
What breeds are predisposed to Malassezia ?
West highland white terrier -> they get everything! Min poodles Bassets GSD Cocker English setters
What conditions predispose animals to Malassezia ?
Allergic dermatitis: food, fleas, allergens
Endocrinopathies
Keratinization disorders
Immunosuppression
Pruritus, malodor
Erythema, greasy scaly plaques
Paronchyia
Otitis externa
In lip folds, interdigital, on ventral neck skin, and in skin folds
Malassezia
Malassezia infection in cats is usually associated with what disease?
Immunosuppressive dz (FIV or FeLV)
How can you diagnose Malassezia ?
Cytology —> Cytobrush, swab, cello tape
Yeast has round to oval, budding peanut shape
(Bowling pins or foot prints
> 2 per high power field is clinically significant
Treatment for Malassezia?
Underlying cause
Topical
- antiyeast shampoo - ketoconazole, miconazole, selenium sulfide (2-3x a week)
- antiyeast rinse - enilconazole
Systemic
-ketoconalole or itraconazole - chronic therapy in some
What shampoos can be used for generalized severe greasy seborrhea?
Selenium sulfide
- selsun blue
- head and shoulders intensive
What shampoos can be used for dry to moderately greasy seborrhea ?
2% ketoconazole + 2%chlorhexidine
1-2% miconazole
How is dermatophytosis transmitted>
Direct contact
Most common sp of dermatophytoisis?
Microsporium canis
Pathogenesis of dermatophytosis ?
Fungal spores can last a long time in the environment
Establish a folliculitis
Young immunosuppressed
Clinical dermatophytosis ?
Focal alopecia lesions
Circular alopecia with scaling
Pruritis rare, unless secondary bacterial infection
—> peripherally expanding alopecia, crust, follicular papules and pustules
—> whole body seborrhea
T/F: dermatophytosis is a zoonosis I
True
30-70% of households with an infected cat will have at least one person develop the disease
How do you diagnose dermatophytosis??
Woods lamp
Microscopy of hair pluck
Fungal culture
—> DTM contains phenol (changes colour at higher pH)
Biopsy
DDX for alopecia, crust, follicular papules, and pustules in dogs
Bacterial folliculitis
Demodecosis
Pemphigus foliceous/erythematosus
How do you treat dermatophytosis?
Underlying disease, source, treat organism
Topical
—> shampoos, ketoconazole
—> creams sustained
—> rinses - enilconazole
Systemic therapy
—> grisofluvin
—> ketoconazole
—> 6-12months
Management of catteries
—> separate infected
—>decontaminate environment
