What is pyoderma?
Bacterial skin infection that can be localised, widespread or generalised
In which species is pyoderma most common?
Dogs then cats, horses, small mammals, farm animals and birds
What is the pathogenesis of pyoderma?
All animals have bacteria on skin with the microflora also consisting of opportunistic pathogens and loss of immune defences or break in physical barrier result in pyoderma infection becoming possible
What can cause break in skin defences leaving animal susceptible to pyoderma?
Skin disease (ectoparasites, allergies, cornification defects, neoplasia, alopecia) Endocrinopathies, metabolic/nutritional problems
What are the main bacteria involved in pyoderma?
Staph pseudintermedius/schleiferi/aureus/hyicus
Other gram +ves such as strep
Coliforms, Pseudamonas, Proteus
How is pyoderma diagnosed?
History, clinical signs, cytology, bacterial culture and search for underlying cause
What history fits with pyoderma diagnosis?
Recent pyoderma, previous response to antibiotic therapy
What clinical signs are seen with pyoderma?
Papules, pustules, epidermal collarettes, draining sinuses
How can cytology for pyoderma diagnosis be achieved?
Impression smear or tape strip stained with DiffQuick or Gram stain
How is a bacterial culture to diagnose pyoderma obtained?
Swab, crust or tissue
What are the three types of pyoderma?
Surface, superficial and deep
What are examples of surface pyoderma?
Hot spot, intertrigo, mucocutaneous pyoderma, bacterial overgrowth
What are examples of superficial pyoderma?
Impetigo and folliculitis
What are examples of deep pyoderma?
Furunculosis, chin acne, bacterial granuloma
How does pain/pruritis vary with different types of pyoderma?
Surface and superficial tend to be pruritic and deep tends to be painful
What is intertrigo?
Skin folds with surface pyoderma
What are the treatment options for intertrigo?
Often long term therapy required
Surgical correction if it is a big fold problem
Antibacterial shampoos/creams
What is the appearance and pathogenesis of mucocutaneous pyoderma?
Looks like cutaneous lupus grossly and histologically
Pathogenesis is poorly understood
What does bacterial overgrowth look like clinically and histologically?
Very red but no lesions and see lots of bacteria but no neutrophils
What is pyotraumatic dermatitis?
Acute, can be painful, bacterial invasion causing disruption of stratum corneum often in large breeds due to an underlying pruritic problem
What is the therapy for pyotraumatic dermatitis?
Topical antibacterial
Anti-inflammatory depending on severity
Treat/correct underlying causes
What do you need to be careful not to confuse pyotraumatic dermatitis with?
Pyotraumatic folliculitis as this is a deep pyoderma and needs different treatment
What is folliculitis?
Inflammation of hair follicle
What is furunculosis?
Deeper inflammation of the hair follicle
What is cellulitis?
Inflammation extending beyond the hair follicle
What is impetigo?
Pustules in inter-follicular epidermis affecting young dogs along ventral abdomen that often responds to topical therapy alone
What is canine superficial pyoderma?
Infection of superficial portion of the hair follicle which is often recurrent and pruritic typically over the ventral abdomen and trunk
What causes canine superficial pyoderma?
> 90% S. pseudintermedius with 80% caused by endogenous strains
What are the typical skin lesions in canine superficial pyoderma?
In order of occurrence over time macule, papule, pustule (transient), epidermal collarettes
What signs other than skin lesions are also seen in canine superficial pyoderma?
Alopecia and pruritis
What are the underlying causes of deep pyoderma?
Same as superficial pyoderma as well as demodecosis and breed specific immune imbalances
What pathogens cause deep pyoderma?
60-80% are Staphylococcal
Gram negatives and anaerobes make up the other 20-40%
How is deep pyoderma diagnosed?
Bacterial culture is always indicated and may have to be from biopsy (don’t put in formalin)
Cytology, skin scrapes, blood tests and imaging for underlying causes
What is the therapy for pyoderma?
Based on cytology while waiting for culture results and then based on susceptibility testing
What skin lesions are seen with deep pyoderma?
Haemorrhagic crusts, draining tracts
What are the underlying causes for acne in dogs and cats?
Often keratinisation defect underlying
Other underlying causes are demodecosis, dermatophytosis, FeLV, FIV and allergies in cats
What animals does acne typically affect?
Short haired dog breeds as young animals or life long
What is the therapy for acne?
Systemic treatment to get disease into remission and then topical treatments to maintain disease free state
What are the characteristics of acral lick dermatitis?
Often large breed dogs with >95% positive bacterial culture
How is acral lick dermatitis treated?
Long term antibiotics and prevent trauma
What are the general treatment options for pyoderma?
Antibacterial medication, treatment/correction of underlying causes
What are the special considerations for pyoderma therapy?
Recurrent, zoonotic implications, antimicrobial resistance
How long do pyodermas need to be treated for?
Superficial - 3 weeks or 1 weeks beyond complete clinical cure
Deep - 4-6 weeks for 2 weeks beyond complete clinical cure
What is dermatophilosis?
Branching filamentous actinomycete that mainly affects ruminants and horses and varies in clinical presentations but can have a significant economic impact
What are the diseases caused by dermatophilosis?
Fleece rot in sheep, mud fever in horses, rain scald in horses