Dermatitis Flashcards
Dermatitis is under what pathological process?
Inflammation and repair
A dermatitis that is superlative/pustular/exudation/neutrophilic is due to?
Bacterial
Auto-immunity
Dermatitis that is proliferative is due to?
Virus
Dermatitis that is vesicular is due to ?
Viral
Auto-immunity
A dermatitis that is granulomatous is due to
Mycobacteria
Fungal
Foreign substance
A dermatitis that is eosinophilic is due to
Allergy
Parasites
A dermatitis that are at the dermal-epidermal junction (interface) is due to
Auto-immunity
Pus in the skin is called
Pyoderma
Pyoderma that is superficial in the epidermis and the hair follicles can be due to what diseases?
Canine superficial spreading pyoderma/ bacterial folliculitis
Impetigo (pustular)
Greasy pig disease (staph hyicus)
Dermatophilosis
A deep pyoderma within the dermis can be due to what diseases
Bacterial furunculosis (eg dog with chin acne
Abscesses
What are predisposing factors for bacterial infection of skin
Disorders of keratinization
- endocrine disease
- chronic dermatitis -allergy or parasite
Immunodeficiency
Anatomical predisposition
What features of dogs skin makes bacterial infection common?
Thin stratus corneum
Lack of lipid seal of hair follicles
High skin pH
What is the most common bacteria infection skin
Staphylococcus spp
-produce exfoliating toxins that cause intraepidermal splitting
Non-follicular pustules which develop into crust often seen in prepubescent puppies
Impetigo
Skin fold pyoderma, where apposed surfaces cause frictional trauma leading to opportunistic bacterial infections
Intertrigo
In a dog you see..
Moist, alopecia, sightly raised well-circumscribed lesions with ulceration/crusting
Pyotraumatic dermatitis (hot spots)
What is the cause of potraumatic dermatitis?
Self trauma -> bacterial infection
-> underlying puritans (eg flea allergy dermatitis)
In a pig you see…
Erythema, pustules, crust
Greasy pig disease (exudation dermatitis)
Caused by staphylococcus hyicus
What are predisposing factors of greasy pig disease?
Other skin lesions, poor nutrition/husbandry, lacerations
This can be fatal in neonatal pigs
You see on your cows and your sheeps..
Pustules, exudate, matted hair/wool, and alopecia on their backs and distal extremities
Dermatophilosis
What are predisposing factors to dermatophilosis ?
Wet weather/humid climate (rain rot)
-prolonged wetting skin allows penetration of epidermis by zoospores
Dermatophilosis is caused by???
Dermatophilus congolensis
Gram + filamentous bacteria
Train track appearance
In a dog you see..
Scaling, erythematous macules, papules, crusts, epidermal collarettes, and alopecia
Canine superficial spreading pyoderma
What is your DDX for canine superficial spreading pyoderma?
Dermatophytosis (ring worm)
Demodicosis
What diagnostics would help you differentiate dermatophytosis vs demodicosis ?
Cytology of pustule/crust -neutrophils with cocci Woods lamp -> ringworm with fluorescence Fungal culture Skin scraping -> demodex
Demodicosis is caused by
Demodex spp mite
What two forms of demodex can dogs have
Localized - face and forelegs (usually in young dogs, self traumatizing)
Generalized (adult onset- associated with systemic disease/neoplasia/endocrinpathy/immunosuppressive therapy)
Dermatophytosis is caused by?
Keratinophylic fungi
- Epiermophyton
- Microsproum
- Trichophyton spp
How do animals get a dermatophytosis infection
Contagious- aquired by contact with scales shed from infected animals
What are predisposing factors do dermatophytosis infections
Young or immunosuppression
Hot/humid environments
Self-limiting disease in healthy animals
Dog with pustular/exudative dermatitis
What is the pathological process and the most likely causes?
Inflammatory
DDX:
Bacterial eg. Staphylococcus
Fungal
Auto-immune
What is a group of autoimmune diseases involving type II hypersensitivity against cell adhesions proteins
Pemphigus
What is the most common/milder form of pemphigus
Pemphigus foliaceous
Pemphigus foliaceous..
where is is usually localized?
What are the lesions?
What is it caused by?
Face, ears, footpads, and clawbeds
Vesicles, pustules, crusts, and ulcers
Spontaneous, drug-induced, or allergic skin disease
“Foliaceous feet face” - Dennis
Pigs
Solid elevations less than 1cm
What pathological process dies this belong to and what is your DDX?
Disturbance of growth
Inflammatory
Histopathology of a papule on a pig shows proliferative dermatitis with ballooning degeneration and intracytoplasmic inclusion bodies.
What is the most likely diagnosis ?
Swine-pox infection
What is the sequence of lesions that arise due to pox viruses?
Macule -> papule -> vesicle -> umbiliated pustule -> crust
What gene do pox viruses contain that leads to epidermal hyperplasia
Epidermal growth factor
You have some livestock in your backyard and you see…
Lameness, anorexia, ptylasm… you investigate further cause thats just the kind of doctor you are…
You find ulcers on their feet, bullas/ulcers in their mouths
What pathological process is this and what’s your DDX?
Degeneration and necrosis
Inflammatory
Virus
- herpes
- pox
- vesicular diseases (FMD, VSV, SVD, and VES)
How do you differentiate a DDX between a group of viruses?
Lab testing
FMD virus infects what sp?
Cattle, pigs, wildlife
VSV virus infects what hosts
Cattle, pig, horse, llama
SVD virus infects what hosts?
Pigs, feral swine
VES infects what hosts?
Pigs
Fish and marine mammals
Cat with vesicular dermatitis on the face
Pustular/vesicular/dermatitis/cheilitis/rhinitis
feline herpes virus 1
Could be calcivirus-> look for ulcers on the tongue)
Pseudo-lumpy skins disease is a vesicular-ulcerative dermatitis due to what virus?
Bovine herpes virus 2
Cows with vesicular-ulcerative mammilities is due to what virus?
Bovine herpes virus 2
