Pyoderma - Bacterial Dermatitis Flashcards
Bacterial overgrowth vs. pyoderma:
with pyogerma, there are commonly degenerative netrophils
What is the most common cause of pyoderma? What 4 toxins does it produce?
Staph pseudintermedius
- beta-lactamase
- protein A - degranulates mast cells, fixes compliment
- proteases
- slime
What other staphylococci are associated with pyoderma?
- S. schleferi - coagulase negative
- S. aureus - zoonotic
What are 4 steps to the pathogenesis of pyoderma? What can contribute to bacterial multiplication?
- increased adherence of S. pseudintermedius to skin cells in atopic animals due to binding site exposure
- inflammatory mediators promote changes to the microclimate
- changes in permeability allow serum leakage and increased humidity of skin
- barrier dysfunction
cutaneous temperature
What are the 2 most common underlying causes of pyoderma? What are some other causes?
- allergic skin disease (atopy) - 42%
- endocrine disease - hypothyroidism (11%), Cushing’s (6%)
- ectoparasites - demodicosis, flea allergy
- cornification disorders
- immunodeficiencies - primary, systemic illness
How does pyoderma progress? What other lesions are seen?
papule –> pustule –> epidermal collarette
- erythema
- crusts, scale
- exudative lesions
- fistulous draining tracts
- alopecia - hair follicles shift phases
What are some differential diagnoses for pustules?
- pyoderma
- autoimmune disease - pemphigus foliaceous, panniculitis
- sterile eosinophilic pustulosis
- dermatophytosis - Trichophyton
- sterile pyogranulomatous dermatitis
What are the major clinical features of pyoderma?
- pruritus
- patchy alopecia to diffuse thinking of hair coat due to folliculitis
vary with depth of infection, duration, primary factors, and severity
What are 5 parts of the diagnostic approach to suspected cases of pyoderma?
- history
- PE, dermatological exams
- dermatology database
- CBC/chem to look for primary causes
- cytology - swab suppurative exudate from pustules or rupture with a 20g needle like a lancet, impression smear of papules after lancing while minimizing contact with surrounding hair –> recommend multiple slides with Dif-Quik and Gram stain
How can epidermal collarettes be samples is suspected cases of pyoderma?
- clip hair
- roll edges up or lift up crusts
- sample underneath - if doing an impression smear, only touch the lesion
Pyoderma, cytology:
likely Staphylococcus pseudintermedius
How are aspirates from pustules properly prepared?
- aspirate exudate onto slide
- immediately spread with a brush before it dries to decrease nuclear streaming compared to slide squashing
What are 4 indications for performing a bacterial culture and sensitivity in suspected cases of pyoderma? What are 2 important aspects to proper technique?
- history of extensive antibiotic treatment
- failure to respond to standard-of-care
- recurring cases
- unexpected cytology - rod-shaped bacteria, filamentous bacteria
- sample intact lesions
- avoid surgical preps that would damage the lesion
What are 4 options for topical antimicrobial therapies used for pyoderma?
- benzoyl peroxide
- mupirocin
- OTC triple antibiotic ointment (Bacitracin)
- SSD
+ antiseptics or enhancers for adjunctiv therapy (Miconazole, Chlorhexidine)
What are 8 active ingredients that work well for shampoo therapy in cases of pyoderma? When are they most useful?
- benzoyl peroxide
- chlorhexidine
- ethyl lactate
- triclosan
- salicylic acid
- sulfur
- tamed iodines
- silver
superficial infections
What are 3 parts of proper technique when using shampoo therapy for pyoderma?
- cool water to reduce pruritus
- contact time of 10 mins
- proper frequency - q 2-7 days
What are 2 options for hydrotherapy in cases of pyoderma? What advantages do they have?
- whirlpools - remove surface debris, reduce pain, increase blood flow to skin
- ultrasonic bathing - bactericidal, cleansing
How often are topical therapies recommended to be performed?
BATHE 1-3x weekly depending on concurrent therapy
SPRAYS, MOUSSE, GEL - apply daily
(expect success within 3-4 months)
What are 4 major limitations to topical therapy in cases of pyoderma?
- client compliance
- exposure of clients to antiseptics - adverse reactions, irritation
- delivery of active agent to skin - hair coat, depends on biocidal activity, concentration, contact time, pH, temperature, biofilm presence, and microorganism
- bacterial resistance (to antiseptics AND systemic antibiotics)
What are the 4 best practices for antimicrobial therapy for cases of pyoderma?
- selection of proper agent based on cytology and culture
- proper dosages
- appropriate time period - 3-4 weeks for most cases, with 1-2 weeks past clinical resolution
- monitor patient and therapy progress - requires rechecks
How long is antibiotic therapy recommended for most cases of pyoderma? What are some ineffective and intermediate antimicrobials?
30 days
INEFFECTIVE - Penicillin, Ampicillin, Amoxicillin, Sulfas, Tetracycline
INTERMEDIATE - Lincomycin, Erythromycin, Chloramphenicol, potentiated Sulfas (high chances of adverse reactions, like arthropathy, euthyroid sick syndrome, and KCS)
What are the 4 most commonly effective antimicrobials used for pyoderma?
- potentiated Amoxicillin - Clavamox
- Cephalexin/Cephadroxil/Cefpodoxime - Simplicef
- Flurorquinolones
- synthetic Penicillin
What 3 cephalosporins are most commonly used to treat pyoderma?
- Cephalexin - BID, 250 and 500 mg capsules
- Cefpodoxime (Simplicef) - SID, multiple sizes
- Cefovecin (SQ Convenia) - q 14 days
Which Fluoroquinolone is not commonly recommended for pyoderma cases?
Ciprofloxacin - wide absorption range
What are 5 limitations of systemic therapy for pyoderma cases?
- client compliance
- adverse effects to patient
- health of patient can affect distribution or metabolism of drugs
- concurrent medications - drug interactions, metabolism (Chloramphenicol, Erythromycin)
- antibiotic resistance
What are the 4 classifications of pyoderma?
- surface - increased colonization, epidermis intact
- superficial - epidermis +/- follicles involved
- deep - extension into dermis
- cellulitis - invasion of fascial planes and aubcutis
What is acute moist dermatitis? What are they most commonly secondary to? How to patients typically present?
hot spots - pyotraumatic dermatitis
trauma, flea infestation, environment
acute onset of rapidly progressive lesions and intensive focal pruritus
Acute moist dermatitis:
What are 3 parts to therapy in cases of acute moist dermatitis? How can it be prevented?
- clip, clean, dry lesions
- antimicrobials - staphylococci
- glucocorticoids to reduce pain and pruritus
control primary factors (atopy, fleas) and use topical antimicrobials and glucocorticoids early
What early topical treatments are recommended for cases of acute moist dermatitis?
- MiconaHex+ Triz spray
- MalAcetic wipes
- antimicrobial sprays
- Genesis spray - Triamcinolone
What is impetigo? What are 3 predisposing factors? How do patients present?
puppy pyoderma - staphylococcal dermatitis in young dogs
- husbandry
- parasitism
- nutrition
subcorneal pustules commonly on ventral abdomen with mild to absent pruritus
Impetigo:
puppy pyoderma
- common on belly
What 2 forms of therapy is recommended for impetigo?
- topicals - shampoo every 3-4 days, sprays (focal), Chlorhexidine/Miconazole
- systemic antimicrobials - 21-30 day course for generalized cases
may resolve spontaneously
What is canine acne? What therapy is recommended>
folliculitis and furunculosis of the chin, commonly seen in younger dogs –> rule out demodicosis
- topcial - SSD, triple antibiotics, etc for focal cases
- systemic - 21-30 days
Canine acne:
What is intertrigo? What breeds are predisposed? Conformation?
skin fold dermatitis common on face, lips, tail bed, and vulva - ideal environment for microbial proliferation –> Staphylococci, Malassezia
- Chinese Shar Pei
- American Cocker Spaniel
- English Bulldog
obese
What management is recommended for intertrigo?
- clean and dry lesion
- topical antimicrobials
- surgical correction
Intertrigo:
can predispose to UTI
Intertrigo:
common in corkscrew tails
- may call for hydrocortisone
Intertrigo:
What is folliculitis? What are 3 common causes?
inflammation of hair follicle
- demodicosis
- dermatophytosis
- bacterial –> S. pseudintermedius
What lesions are associated with folliculitis?
- papules, pustules
- epidermial collarettes
- alopecia
- “lumpy bumpy” skin
What breeds are most commonly affected by folliculitis? What does it result in?
shorthaired - Doberman Pinscher, English Bulldog, Dalmatian
shift in follicles to telogen, where hairs are easilty dislodged –> patchy “moth-eaten” alopecia
Folliculitis:
patchy alopecia
Folliculitis:
- patchy
- crusts
- epidermal collarettes
Folliculitis, Doberman:
- patchy, thin coat
- will leave tons of hair on exam table
Folliculitis, Dalmatian:
- palpate and rub skin in direction of hair coat to better appreciate papules
- hair sticking out
- focal alopecia
What therapies are recommended for folliculitis?
- TOPICAL - bathe q 3-7 days with antimicrobial champoos –> Chlorhexidine, Miconazole/Chlorhexidine*, Benzoyl peroxide OR Mupirocin/BPO for focal lesions
- SYSTEMIC - antimicrobials (Cephalexin) for 30 days
What is furunculosis? What lesions are characteristic?
progression of folliculitis where follicles rupture, releasing their debris into the dermis, which causes a FB-type reaction
fistulous tracts +/- papules, nodules, permanent (cicatricial) alopecia, mild to moderate pruritus
Furunculosis:
squeeze –> serosanguinous exudate from fistulous tracts
Furunculosis:
Furunculosis:
fistulous tracts common over pressure points
Furunculosis:
- fistulous tracts with serosanguinous exudate
- heavy head = pressure point
What therapies are recommended for furunculosis?
- TOPICAL - whirlpools/ultrasonic baths, antibacterial shampoos are of little value
- SYSTEMIC - antibacterial therapy for 30-60 days, choice based onf C&S
What is post-bathing furunculosis? What is the most common cause?
furunculosis developing with pain and pruritus within 2-7 days after bathing –> can look like IVDD!
Pseudomonas aeruginosa contaminated shampoo + trauma
How is post-bathing furunculosis diagnosed? Treated?
- cytology - rod-shaped G- bacteria
- C&S
topical and systemic antimicrobial therapy
Nasal/mucocutaneous pyoderma:
- remove heavy crust and perform an impression smear underneath
- common at nose and lip margins
- treat with systemic antimicrobials for 21-30 days, topical is difficult due to location
Interdigital pyoderma:
furunculosis
Nasal furunculosis:
cytology!
Pressure point pyoderma:
behavioral - continuous rubbing ventrum on carpet
What is acral lick dermatitis? What is the most common cause?
non-behavioral folliculitis/furunculosis on extremities associated with focal intense pruritus
S. pseudintermedius
GSD pyoderma:
furunculosis!
What is paronychia? How is it treated?
claw (nail) bed infection —> patient may present sore and lame and draining tracts may form
systemic antimicrobials + foot soak in Miconazole/Chlorhexidine
What is the most common cause of cat pyoderma?
puncture wounds from fights –> most commonly found on forelimbs and tail base
- caused by Staph and Pasteurella
- commonly reaches deep and progresses to cellulitis without proper treatment
What are 4 parts of managing deep pyoderma?
- systemic therapy
- whirlpool
- surgical intervention to open/remove fistulous lesions or FBs
- client education - long-term management, identify primary/predisposing factors
wait until infection is treated to check thyroid levels –> euthyroid sick syndrome
What is treatments are recommended for pyoderma maintenance?
- intermittent baths - Chlorhexidine, BPO, combos
- regular use of wipes and sprays on trouble spots –> feet, lip folds, facial folds
What are the 5 best antibiotics for treating MRSP cases? What else is recommended to add to treatment?
- Clindamycin
- TMS
- Chloramphenicol
- Doxycycline
- Rifampin
- monitor ALT!
topical therapy more frequently - bleach at 120 mL per 4 L (1 gal)
What are some dermatological conditions that can mimic pyoderma?
- juvenile cellulitis
- dermatophytosis - Trichophyton
- autoimmune disease - pemphigus foliaceus/erythematosus, panniculitis, drug reactions
- FB reactions
- sterile pyogranulomatous diseases
- eosinophilic folliculitis/furunculosis,
- sterile eosinophilic pustulosis
- intertrigo due to yeast infection
- callus/hygroma
- cutaneous lesions of systemic mycoses
- subcorneal pustular dermatosis
- neoplasia
