Bacterial dz Of Thr Skin Flashcards
What are the 2 forms of hairy heel warts/ digital dermatitis?
Erosive/ reactive form (Europe)
Proliferative/ wart-like form (NA)
Which bacteria causes hairy heel warts?
Treponema phagedenis, T. vincentii, T. denticola
Dichelobacter nodosus (synergizing agent)
Campylobacter spp. and Prevotella
What is the most common location of hairy heel wart?
Flexor commiserate of the interdigital space
Less common : dorsal surface of the foot and around dewclaws
Dermatophilosis (Rain Scald or Lumpy Wool)
Caused by Dermatophilus congolensis (G+, filamentous, branching)
Predisposing factors for dermatophilosis
Cannot penetrate healthy skin
Prolonged wetting
Mechanical damage to the skin
Gross lesions of dermatophilus
Raised, circular, thick, laminated, gray-brown scale crusts penetrated by tufts of hair
Underlying epidermis moist and red
Where are dermatophilus lesions located?
Along the dorsal midline between the withers and rump
Laterally onto the flanks, thoracic wall, shoulders and neck
Pyoderma
Bacterial infection of the skin producing pus
Primary/ simple or secondary/ complex and superficial or deep
Primary/ simple pyoderma
Caused by one time or single event with a specific dz pattern (flea allergy)
Secondary/ complex pyoderma
Subsequent to reoccurring event or underlying dz (demodex, hypothyroidism)
What causes pyoderma?
Staph. Pseudintermedius
Common areas of pyoderma
Lip, facial, vulvar, tail and neck folds, axillary area, dorsal or plantar interdigital areas
Pressure points (elbows snd hocks)
Superficial pyoderma
Epidermis and upper infundibulum of hair follicles
Heals without scaring
Short duration
Gross lesions associated with superficial pyoderma
Erythema, alopecia, papules, pustules, crusts, epidermal collarettes,
Microscopic lesions associated with superficial pyoderma
Intradermal pustular dermatitis (impetigo)
Superficial folliculitis
Neutrophils
Deep pyoderma
Involves the hair follicles, dermis , +/- subcutis
Heals with scarring, involves regional LNs, systemic illness
Gross lesions of deep pyoderma
Pustules with erect hairs emerging from center
SQ nodules, abscesses, ulcers, fistulous tracts
Microscopic lesions of deep pyoderma
Deep folliculitis
Nodular to diffuse suppurative or pyogranulomatous dermatitis or panniculitis
Porcine impetigo (Greasy Pig Dz, exudative epidermatitis)
Staph. Hyicus
Predisposing factors: cutaneous lacerations and poor nutrition
Lesions associated with porcine impetigo
Gross: thickened epidermis with scaling
Histo: sub corneal pustular dermatitis extending to hair follicles
Swine erysipelas (Diamond skin Dz)
Erysipelothrix rhusiopathiae
G+ bacillus
Acute (highly fatal septicemia) and chronic dz
Pathogenesis of diamond skin dz
Cutaneous lesions from bacterial embolization to skin during sepsis
Lesions caused by vasculitis, thrombosis, and ischemia
Area of the skin not receiving blood supply
Chronic swine erysipelas
Polyarthritis
Endocarditis (vegetative)
Necrosis of the skin (diamond skin)
Acute septicemic erysipelas
Petechial hemorrhages over serous membranes
Spleen and LNs may be enlarged and reddened
Bluish discoloration of skin may occur
