Pyoderma Flashcards
Staphylococcus pseudintermedius
- found primarily on hair vs. skin in the anal region, nasal carriage.
- Produces potent toxins/enzymes
- B-lactamase- helps break down antibiotics such as penicillin and amoxicillin
- Protein A : degranulates mast cells, fixes compliment
- Proteases- irritates nerves and triggers pruritus
Pathogenesis of bacterial infections
- increased adherence of S. pseudintermedius to skin cells in atopic animals
- inflammatory mediators promote changes in microclimate
- changes in permeability may allow serum leakage and increased humidity on the skin
- Cutaneous temperature changes may also contribute to bacterial multiplication
- Barrier dysfunction
Primary factors of Pyoderma
Allergic Skin diseases (Atopy**)
Ectoparasites
Disorders of cornification
Endocrine disease (hypothyroidism**)
Immunodeficiency
What are differential diagnoses for pustules
- pyoderma
- autoimmune disease
- Pemphigus foliaceus : pustules
- Panniculitis: draining tracts
- Sterile eosinophilic pustulosis
- Dermatophytosis
- Sterile pyogranulomatous dermatitis
What are clinical features of Pyoderma?
pruritus
patchy alopecia to diffuse thinning of hair coat
Signs vary with depth of infection, duration of infection, primary factors, and severity of infection
What is the diagnostic approach for pyoderma
cytology is an absolute must
Physical and dermatological exams
Dermatology data base
CBC, biochemistry profile to look for primary causes
Acute Moist Dermatitis
“Hot Spots”
Secondary to trauma, flea infestations, environmental influences
Animals present with acute onset of lesions. Rapidly progressive
Intensive focal pruritus
How should you make a slide of a pyoderma case
cotton swab slide prep
roll prep
Pustule cytology
Papule cytology
Impression after lancing
In what situation would you utilize a shampoo therapy for a pyoderma case?
Useful for superficial infections
Why are whirlpools efficacious for pyoderma cases?
They remove surface debris, reduce pain, and increase blood flow to the skin
What are limitations of topical therapy for Pyoderma cases?
- Client compliance
- Exposure of clients to antiseptics
- Delivery of active agent to the skin such as hair coat
- Evidence of increasing bacterial resistance to antiseptics
- Evidence of increasing bacterial resistance to antibiotics after exposure to biocides/antiseptics
What are effective antibiotic options to treat pyoderma cases?
fluoroquinolones, potentiated amoxicillin, synthetic penicillins, cephalexin
Waht are examples of Cephalosporins
Convenia
Simplicef
Cephalexin
Are cephalosporins a good choice for treating a pyoderma case?
yes this is the first tier of drugs to choose from
What are examples of Fluoroquinolones?
Zeniquin
Baytril
Ciprofloxacin
Orbax
What are limitations of systemic therapy
client compliance
adverse effects to the patient
general health of patient - may affect distribution or metabolism of drugs
concurrent medications
ANTIBIOTIC RESISTANCE
What are classifications of pyoderma (4)
- Surface- increased colonization, epidermis remains intact
- Superficial: epidermal and/or hair follicles involved
- Deep: extension of infection into dermis
- Cellulitis: invasion of fascial planes and subcutis
Acute moist dermatitis: Therapy
Clip, clean, and dry lesions
Antimicrobials vs Staph. (topical vs. systemic)
Glucocorticoids to reduce pain and pruritus
Prevention
- control primary factors
- topical antimicrobial/glucocorticoids early
Impetigo
“Puppy pyoderma”
- staphylococcal dermatitis in young dogs
- Predisposing factors may include husbandry, parasitism, nutritional factors
- Pruritus is absent to mild
- Lesions are subcorneal pustules
what are therapies for Impetigo
Lesions may resolve spontaneously
- topical therapy
- Mupirocin or BPO gel
- BPO shampoos every 3-4 days
- Systemic antimicrobial therapy
- For more generalized cases
- 21-30 day course of appropriate drug
Canine Acne
- Essentially folliculitis (and furunculosis) of the chin
- Often seen in young dogs (rule-out demodicosis!!!)
- May “Resolve” spontaneously at maturity
- Therapy
- Topical: BPO gel or mupirocin
- Systemic: 21-30 days of appropriate drug
Intertrigo
Skin Fold Dermatitis
- skin folds provide an ideal environment for microbial proliferation
- Bacteria (Staphylococci)
- Yeast (Malassezia spp.)
- Breed predisposition! Brachycephalic breeds
- Management
- clean and dry the lesion
- Appropriate antimicrobials (generally topical)
- Surgical correction
Folliculitis
what is it and what are the major differentials
inflammation of the hair follicle superficial or deep. this is associated with patchy alopecia.
-papules, pustules, epidermal collarettes (lumpy-bumpy skin)
Common causes: Demodicosis, dermatophytosis, Staph. pseudintermedius
therapy for folliculitis
topical is a good option if the owners are willling and able
- Bathe every 3-7 days with antimicrobial shampoos
- Mupirocin or BPO for focal lesions
Systemic
- antimicrobials for 30 days
Furunculosis
progression of folliculitis
Follicles rupture, releasing debris into the dermis -> foreign body-type reactions DRAINING TRACKS
Lesions include papules, nodules, pustules etc
Destruction of the follicle results in permanent alopecia
Pruritus is mild to moderate
therapy for Furunculosis
- Topical
- Classically antibacterial shampoos are of little value
- Whirlpools, US treatment are useful
- Systemic therapy
- Appropriate antibacterial therapy for 30-60 days or as needed
- Choice of antimicrobial based on cytology or culture results
What is post-bathing Furunculosis
- Lesions develop with pain and pruritus 2-7 days after bathing
- Pseudomonas aeruginosa
- contaminated shampoo + trauma - if the shampoo has been sitting around for a while, it is usually a Pseudomonas bacteria present
- Cytology Rod shaped Gram- bacteria
- Culture and Sensitivity is recommended
paronychia
claw bed infection
Management of Deep Pyoderma
diagnostics: Database, bacterial culture, endocrine evaluations
Systemic therapy with appropriate agents
Whirlpool
surgical intervention to open remove fistulous lesions
Client education: long-term management, identify primary factors and predisposing factors
Methicillin Resistance
This is a zoonotic consideration for owners
MRSP is rising in incidence. Antibiotics that remain our best choices such as Clindamycin, chloramphenicol.
Topical therapy is used more frequently
Dermatologic Conditions that Mimic Pyoderma
- Juvenile cellulitis
- Dermatophytosis (Trichophyton sp. )
- Autoimmune issues
- Foreign body reactions
- Sterile pyogranulomatous diseases.
