Bacterial Skin Diseases (Marsella) Flashcards
Cutaneous bacteria
Bacteria found on surface and in hair follicles
Resident cutaneous bacteria
Multiply (ex. S. pseudointermedius)
Transient cutaneous bacteria
Do not multiply (ex. E. coli, Proteus)
Pathogen cutaneous bacteria
S. pseudointermedius, S. schleiferi
Feline skin flora
- Staph intermedius
- Staph aureus
- Staph simulans
- Staph epidermis
- Staph xylosus
- Pastruella
Equine skin flora
- Staph aureus
- Staph intermedius
- Dermatophilus congolensis
Porcine skin flora
Staph hyicus
Physical defense mechanisms of skin
- Hairs
- Turnover of stratm corneum
Chemical defense mechanisms of skin
- Sebum
- Fatty acids
Immune defenses of skin
- Lymphocytes
- Langerhans cells
- Keratinocytes
- Cytokines
Microbial defenses of skin
Competition from normal skin flora
Pyoderma
Pus in the skin = bacterial infection w/ in the skin
Classificaitons of pyoderma
- Primary vs secondary
- Site
- Pathogen
- Depth (surface, superficial, deep)
Surface pyoderma
- Pyotraumatic dermatitis (hot spot)
- Skin fold pyoderma (intertrigo)
Pyotraumatic dermatitis
- “Hot spot”
- Thick or long haired breeds more common
- Warm weather
- Rapid onset
- Self-induced
- Underlying problem
- DOGS ONLY
Underlying problems causing pyotraumatic dermatitis
- Flea allergy
- Ectoparasites
- Allergic skin diseases
- Anal sac diseases
- Otitis externa
- Contact
- Ocular
Furuncle
Follicular abscess. Ruptured folliculitis
“Boil”
Folliculitis/Furunculosis in relation to pyotraumatic dermatitis
Can initiate or complicate a hot spot. Deeper infection (involves follicle).
Diagnosis of pyotraumatic dermatitis
- Hx
- Clinical signs
Pyotraumatic dermatitis therapy
- Clip & clean area
- Topical astringents
- Break the itch cycle w/ glucocorticoids
- +/- systemic abx
- ID and correct underlying cause
Skin fold pyoderma (intertrigo)
Surface infection in warm, moist folds. Bacteria and yeast.
Areas skin fold pyoderma manifests
- Body fold (Shar pei, Basset hounds, achondrodysplastic dogs)
- Lip fold (Cocker/Springer spaniels, setters..causes halitosis)
- Facial fold (brachycephalic dogs, Shar pei)
- Vulvar fold (obese bitches, spayed before 1st estrus)
- Tail fold (screw tail pyoderma, Bostons, English bulldogs)
Skin fold pyoderma therapy
- Medical
- cleaning
- wipes
- Surgical
Superficial pyoderma
Pustules are present in the stratum corneum or inside the hair follicles
Ex. impetigo, superficial bacterial folliculitis
Impetigo
- “Puppy pyoderma”
- Subcorneal pustules in glabrous (hairless) areas
- Not contagious
Impetigo diagnosis
Signalment & clinical signs
Impetigo therapy
- Topical therapy (benzoyl peroxide medicated shampoo)
- Ensure clean environment
- +/- abx (severe, persistent cases)
Agents that cause Folliculitis
- Bacteria (Staph pseudointermedius)
- Parasites (Demodex)
- Fungal (Dermatophyte)
Primary lesions of bacterial folliculitis
- Papules
- Pustules
- Erythematous macules
Secondary lesions of bacterial folliculitis
- Circular crusts
- Collarettes
- Focal scale
- Alopecia
- Hyperpigmented macules
Bodily distribution of bacterial folliculitis
Truncal. Most diagnostic lesions on ventral abdomen.
Bacterial folliculitis diagnosis
- Clinical signs
- Skin scrape to R/O other causes
- Cytology
- Culture
- Biopsy
- Response to therapy
Bacterial folliculitis therapy
- Abx (continue 7-10 days past clearance of clinical signs)
- Topical therapy
- ID & correct underlying cause
Equine folliculitis bacteria
- Staph
- Dermatophilus congolensis
Dermatophilosis (other names)
- Strawberry foot rot
- Rain scald
- Rain rotscald
- Rain rot
- Lumpy wool
- Streptothricosis
Dermatophilosis
- Gram + aerobic or facultative anaerobe
- Actinomycete
- During rainy season
- Horses, sheep, cattle, goats, zoonotic
3 Factors of dermatophilosis infection
- Chronic carriers (zoospores survive in scabs for months)
- Moisture, rain, sweating
- Break in skin integrity
Dermatophilosis transmission
- mechanical transmission - flies
- contaminated clippers
normal skin is resistant to infection
Dermatophilosis clinical features
- Dorsal surfaces
- Thick “paintbrush” crusts
- Hair easily removed exposing moist pink skin
- Green exudate & erosions
- Dry crusts, scale, alopecia
- More painful than puritic
Dermatophilosis diagnosis
- Clinical features
- Cytology
- “Railroad track” appearance of bacteria
Dermatophilosis treatment
- Self limiting
- Remove from rain
- Benzoyl peroxide and chlorohexadine shampoo
- Systemic abx for minimum of 2 wks
- TMP-sulfa is drug of choice
- Penicillin
Staphylococcal folliculitis/furunculosis
- Staph aureus
- Complication of most pruritic diseases
3 main syndroms of staphylococcal folliculitis/furunculosis
- Trunk
- Tail
- Pastern
Truncal folliculitis
- Type of staphylococcal folliculitis
- Heat rash, saddle rash
- Painful, papulonodular eruption
- Saddle areas & can spread
Tail pyoderma
- Type of staphylococcal folliculitis/furunculosis
- Pustules arise on dorsal area of tail
- Induced by tail rubbing, increases self induced trauma
- Pruritic
Exudative epidermis
- S. hyicus
- Toxins are absorbed (liver & kidney dz)
- In sucking piglets, dz usually confied to individuals
Deep pyoderma
- Furunculosis
- Abscesses, cellulitis, panniculitis
Furunculosis
- Deep pyoderma
- Hair follicles rupture and infection spreads to dermis
- Infection may be mixed
Clinical signs of furunculosis
- ulcers
- fistulous tracts
- pustules/bulla
- cellulitis
Furuncolosis diagnosis
- R/O demodex
- Cytology
- Culture
- Biopsy
- Response to abx
Furunculosis therapy
- Abx (minimum of 2 months)
- if multiple bacteria on culture, address Staph 1st
- Topical therapy
- ID & tx underlying cause
- Immunotherapy
- Avoid steroids
Abscess
- Result of trauma/wounds/foreign bodies
- Common in male cats - Pastruella
- Establish drainage & systemic abx
Recurrent staphylococcal pyoderma
- Comes back after a few months
- Differentiate from persistent (comes back in 2 wks, inappropriate therapy)
- Look for underlying cause (demodex, dermatophyte, atopy, endocrine/metabolic, physical)
Canine Juvenile Cellulitis
- “Juvenile pyoderma”, “puppy strangles”
- Idiopathic
- Not really an infection
- Immune mediated response
- Goldens predisposed
Canine juvenile cellulitis clinical signs
- typically young puppies
- edema of face, lips, pinna
- Pustules
- Lymphadenopathy
- Fever
- Depression
Canine juvenile cellulitis therapy
- High dose glucocorticoids
- be sure to R/O demodex (steroids = bad)
- +/- abx for secondary infections
