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Dermatology- Pyoderma, Folliculitis

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sihirlifil's version from 2017-09-20 16:01

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Question Answer
Hair follicle diseases:Bacterial, Demodex, Dermatophyte
Alopecia can be from? How do you differentiate?Can fall out by itself, or animal removes it
Easily epilated (comes out when you pull gently): folliculitis
Ddx for folliculitis (3)Bacterial infection
Demodicosis
Dermatophytosis
If you see epidermal collaretts, dx tests?Skin scrape, fungal culture, glass slide impression smear
What to keep in mind when doing skin scrape for demodex?Has to be deep! Demodex lives in hair follicle, which extends to dermis, so scrape until you get blood
Macerated tissue culture is good for?Seeing important bacteria (i.e. not normal inhabitants of skin) who live deep
Go-to class of drugs?1st generation cephalosporins
Acute moist dermatitis (hot spot): predisposing factors?Heat, moisture (Grenada)
Acute moist dermatitis (hot spot): CS?Alopecic spots, pain, pruritis, excoriations
Acute moist dermatitis (hot spot): dx tests?Cytology
Ddx bacterial infection or if just inflammatory
Hot spot on the face usually means?Deep infection (need antibiotics)
Acute moist dermatitis (hot spot): treatment?Sedate
Pain management
Clip & clean
Cephalosporin 1st line antibx (if indicated)
Topical/systemic steriods (don't use steroids & antibx together)
Acute moist dermatitis (hot spot): type of infection?Superficial
Fold pyoderma: predisposing factors?Moisture, friction between folds (opportunistic)
Fold pyoderma: CS?Pruritis, pain, odor
Fold pyoderma: dx tests?Swab & cytology
Collect debris --> slide --> Diffquik
Fold pyoderma: tx?Topicals (good for surface infection)
Challenge with using topicals for fold pyoderma?Greasy/sticky/powdery ointments can cause more friction (cream-based or spray better)
Cocci or rod harder to treat?Rod
Fold pyoderma: type of infection?Surface
Puppy pyoderma: type if infection?Superficial
Puppy pyoderma: etiology?Can be parasites, stress, malnutrition as underlying cause
Puppy pyoderma: CS?Large flaccid pustules not associated with hair follicle
Not painful or pruritic!
Age cutoff for puppy pyoderma5-6 months old (weanlings)
Puppy pyoderma: dx tests?Cytology (bacteria)
Puppy pyoderma: tx?Topical CHG shampoo, treat secondary problems (parasites etc.)
Don't want to use systemic antibx in young puppies if can avoid
Complication of puppy pyoderma?2ry ringworm
Bacterial folliculitis: type of infection?Superficial
Bacterial folliculitis: etiology?
Bacterial folliculitis: CS?Papules, pustules, epidermal collarettes
Pruritis
Chronic: alopecia, lichenification, hyperpigmentation, hair epilates easily at margins
Top cause of recurrence of bacterial folliculitis?Atopy
Allergies to pollens, molds, dust
If bacterial folliculitis is recurrent, do what?Look for underlying cause!
#1 bacterial cause of folliculitisStaph pseudointermedius
Bacterial folliculities: tx?Antibiotics, minimum 3 weeks w/ 3 week recheck
Tx of choice = 1st gen cephalosporins (cheap, available, effective) (3rd gen, clavamox, clindamycin, sulfa? fluoro?)
Treat as if it's S. pseudointermedius, C&S if fails (could be staph)
T/F Steroids are an option for treating superficial pyodermaFalse! Need immune response to heal infection --> get rid of pruritis
Topical shampoos for superficial pyoderma?Benzoyl peroxide (flushes follicle)
Chlorhexidine
Ethyl lactate
Antipruritic rinses (oatmeal!)
Important for shampoos:Contact time
How do you treat with topical shampoos?Bathe 2x/week, 3 week recheck
Recurrence = More than 1! Goes away completely then comes back (not the same as chronic)
Ddx recurrent superficial pyoderma: pruritic?Atopy
Food allergy
Scabies
Flea allergy
Ddx recurrent superficial pyoderma: nonpruritic?Demodex (always check!)
Endocrine (hypothyroid)
Immune
Steroids (overuse!)
Staph hypersensitivity: etiology(Doesn't exist, lol)
Treatment for "staph hypersensitivity?"Staphage lysate
Deep pyoderma: etiology? what pathogen?Multifactorial
Main one still Staph psudointermedius (resistant); staph aureus, schleiferi; e coli; proteus; pseudomonas; anaerobes; corynebact; actinomyces; fungal
What's special about Staph aureus (deep pyoderma)?Human pathogen! Patient can get it from owners. Also wear gloves when taking samples (MRSA)
Deep pyoderma: CS?Thickened skin, deep crusts
Comedones, ulcerations, large papules, exudation, drainage tracts
Furunculosis & folliculities on biopsy
Deep pyoderma likes to be where?Mucocutaneous junctions (lips)
Ddx autoimmune
Deep pyoderma: diagnostics?Impression smear cytology (with gloves!)
Macerated tissue culture
Histopathology
How do you take a macerated tissue culture?Select a site that isn't ulcerated (e.g. intact pustule), sedate & local lidocaine, surgical scrub to kill bacterial on surface, aseptic punch biopsy, submit to lab for maceration
Indications to do bacterial culture?Presence of bacteria on histopathology (atypical)
Rod bacteria on cytology
Poor response to therapy
Recurrent infections
Deep pyoderma: tx options?Antibiotics: 4 week treatment, 3 week recheck
Mupiricin great (but resistance in humans)
Silver sulfadiazine great for deep infections and wound healing (irritating to people)
Deep moist dermatitis: predisposing factors?Long, dense hair coats & humid weather
Deep moist dermatitis: dx?Cytology (lots of bacteria!)
Deep moist dermatitis: tx? same as superficial?Need systemic antibx! Topicals won't cut it
(Can use steroids if needed to control pruritis)
Pododermatitis: etiology?Allergy, demodex, resistant bacteria, endocrine
Interdigital lesions are almost always?Deep pyoderma
Pododermatitis: dx?Scrape
Cytology
Culture
Lab work (bloodwork helps to not miss root of the problem)
Biopsy (macerated tissue!)
Pododermatitis: lesions?Granulomatous in interdigital spaces of dogs
Ulcerative, can form pustules, drainage tracts, bullae, form scar tissue
NOT CYSTS
Pododermatitis: tx options?Antibiotics 6 weeks minimum
Work up underlying allergic skin disease (or demodex, resistant bacteria, endocrine)
CO2 laser for tissue ablation (cauterizes & sterilizes)
Surgical debridement
**Useful for antibx selectionCulture & sensitivity
**In vitro results =/=In vivo efficacy
**Factors for poor effecacy (3)Compliance
Tolerance
Individual variability
memorize

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