Bacterial skin diseases Flashcards
(36 cards)
Define pyoderma
= bacterial skin infection. Can be localised, widespread or generalised. Very common and important. Can be itchy or painful. Dog most commonly. Also cats, horses, small mammals, farm animals and birds.
What are some triggering factors for bacteria skin disease? 5
- breaks in physical skin barrier
- loss of immune defences/immune imbalance
- Skin disease (ALLERGIES, ectoparasites, cornification -defects, neoplasia, alopecia)
- ENDOCRINOPATHIES
- metabolic/nutritional problems
What bacteria are involved in pyoderma? 6
- S.pseudintermedius*
- S.schleiferi subsp coagulans
- S.aureus
- S.hyicus (pigs)
- Other gram positives (Strep)
- Gram negatives - Coliforms, Pseudomonas spp., Proteus
Dx - pyoderma - 4
- Hx - recurrent, previous response to ABs
- CS - papules, pustules, epidermal collarettes, draining sinuses
- Cytology - tape strip, impression smear + gram stain and Diffquik
- Bacteria - and sensitivity, swab, crust and tissue
What are the 3 main types of pyoderma?
SURFACE - hot spot, intertrigo (skin folds), mucocutaneous, bacterial overgrowth
SUPERFICIAL - impetigo (puppies), folliculitis
DEEP - furunculosis, ache, bacterial granuloma
Tx - surface pyoderma
- long term therapy
- surgical correction?
- antibacterial shampoos/creams
What is pyotraumatic dermatitis also known as?
= hot spot and acute moist dermatitis
Describe pyotraumatic dermatitis
acute, painful, self-trauma –> bacterial invasion, disruption of the stratum corneum, often large breeds (Retriever), underlying pruritic problem (FAD, anal sac irritation, otitis)
Tx - pyotraumatic dermatitis
- topical ABs
- anti-inflammatories (depends on severity)
- treat/correct underlying causes
What are satellite lesions?
lesions found around the main lesion. suggests haematogenous spread therefore deep pyoderma
Which tx is contraindicated in deep pyoderma?
GCs
Describe impetigo
- pustules in interfollicular epidermis
- young dogs
- ventral abdomen
- often responds to topical therapy alone
What is canine superficial pyoderma?
- Infection of the superficial portion of the hair follicle.
>90% cases are S.pseudintermedius (>80% of these are endogenous strains) - often recurrent and pruritic
- typically ventral abdomen and trunk
What are the 4 commonest lesions in canine superficial pyoderma?
Papules, epidermal collarettes, alopecia and pruritus
Clinical presentation varies with coat length
Outline lesion progression with time in canine superficial pyoderma
Macule -> papule –> pustule –> epidermal collarette –> alopecia and pruritus.
Clinical presentation varies with coat length
What are the 3 main types of deep pyoderma?
- furunculosis
- acne
- bacterial granuloma
Pathogens - deep pyoderma
- Staph (60-80%)
- Gram negatives
- Anaerobes
Dx - deep pyoderma
- Bacterial culture always indicated, may have to be from tissue (DON’T put skin biopsy in formalin)
- Cytology, sin scrapes etc, blood tests, imaging for underlying causes.
Tx - deep pyoderma
- based on cytology while waiting for culture results
- based on susceptibility testing thereafter
What are the underlying causes for deep pyoderma?
- As for superficial pyoderma, demodicosis.
- Breed specific immune imbalances
What may cause acne?
Dogs (and cats)
Often chronic and young animals
?Keratinisation defect
CAT: demodicosis, dermatophytosis, FeLV, FIV, allergies
DOG: short-haired breeds, any other causes
Tx - acne
Systemic - to achieve initial remission
Topical - to maintain remission
What does an acral distribution of a skin problem mean?
it affects distal portions of the limbs and head
Outline acral lick dermatitis
- often large breed dogs
- often chronic
>95% positive bacterial culutre - Tx = long term antibiosis and prevent trauma.
- Causes - underlying joint disease, allergy, (behaviour - boredom)
