Bacterial Skin Disease

Question 1

What is pyoderma?

Answer 1

Bacterial skin infection that can be localised, widespread or generalised

Question 2

In which species is pyoderma most common?

Answer 2

Dogs then cats, horses, small mammals, farm animals and birds

Question 3

What is the pathogenesis of pyoderma?

Answer 3

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

Question 4

What can cause break in skin defences leaving animal susceptible to pyoderma?

Answer 4

Skin disease (ectoparasites, allergies, cornification defects, neoplasia, alopecia)
Endocrinopathies, metabolic/nutritional problems

Question 5

What are the main bacteria involved in pyoderma?

Answer 5

Staph pseudintermedius/schleiferi/aureus/hyicus
Other gram +ves such as strep
Coliforms, Pseudamonas, Proteus

Question 6

How is pyoderma diagnosed?

Answer 6

History, clinical signs, cytology, bacterial culture and search for underlying cause

Question 7

What history fits with pyoderma diagnosis?

Answer 7

Recent pyoderma, previous response to antibiotic therapy

Question 8

What clinical signs are seen with pyoderma?

Answer 8

Papules, pustules, epidermal collarettes, draining sinuses

Question 9

How can cytology for pyoderma diagnosis be achieved?

Answer 9

Impression smear or tape strip stained with DiffQuick or Gram stain

Question 10

How is a bacterial culture to diagnose pyoderma obtained?

Answer 10

Swab, crust or tissue

Question 11

What are the three types of pyoderma?

Answer 11

Surface, superficial and deep

Question 12

What are examples of surface pyoderma?

Answer 12

Hot spot, intertrigo, mucocutaneous pyoderma, bacterial overgrowth

Question 13

What are examples of superficial pyoderma?

Answer 13

Impetigo and folliculitis

Question 14

What are examples of deep pyoderma?

Answer 14

Furunculosis, chin acne, bacterial granuloma

Question 15

How does pain/pruritis vary with different types of pyoderma?

Answer 15

Surface and superficial tend to be pruritic and deep tends to be painful

Question 16

What is intertrigo?

Answer 16

Skin folds with surface pyoderma

Question 17

What are the treatment options for intertrigo?

Answer 17

Often long term therapy required
Surgical correction if it is a big fold problem
Antibacterial shampoos/creams

Question 18

What is the appearance and pathogenesis of mucocutaneous pyoderma?

Answer 18

Looks like cutaneous lupus grossly and histologically

Pathogenesis is poorly understood

Question 19

What does bacterial overgrowth look like clinically and histologically?

Answer 19

Very red but no lesions and see lots of bacteria but no neutrophils

Question 20

What is pyotraumatic dermatitis?

Answer 20

Acute, can be painful, bacterial invasion causing disruption of stratum corneum often in large breeds due to an underlying pruritic problem

Question 21

What is the therapy for pyotraumatic dermatitis?

Answer 21

Topical antibacterial
Anti-inflammatory depending on severity
Treat/correct underlying causes

Question 22

What do you need to be careful not to confuse pyotraumatic dermatitis with?

Answer 22

Pyotraumatic folliculitis as this is a deep pyoderma and needs different treatment

Question 23

What is folliculitis?

Answer 23

Inflammation of hair follicle

Question 24

What is furunculosis?

Answer 24

Deeper inflammation of the hair follicle

Question 25

What is cellulitis?

Answer 25

Inflammation extending beyond the hair follicle

Question 26

What is impetigo?

Answer 26

Pustules in inter-follicular epidermis affecting young dogs along ventral abdomen that often responds to topical therapy alone

Question 27

What is canine superficial pyoderma?

Answer 27

Infection of superficial portion of the hair follicle which is often recurrent and pruritic typically over the ventral abdomen and trunk

Question 28

What causes canine superficial pyoderma?

Answer 28

>90% S. pseudintermedius with 80% caused by endogenous strains

Question 29

What are the typical skin lesions in canine superficial pyoderma?

Answer 29

In order of occurrence over time macule, papule, pustule (transient), epidermal collarettes

Question 30

What signs other than skin lesions are also seen in canine superficial pyoderma?

Answer 30

Alopecia and pruritis

Question 31

What are the underlying causes of deep pyoderma?

Answer 31

Same as superficial pyoderma as well as demodecosis and breed specific immune imbalances

Question 32

What pathogens cause deep pyoderma?

Answer 32

60-80% are Staphylococcal | Gram negatives and anaerobes make up the other 20-40%

Question 33

How is deep pyoderma diagnosed?

Answer 33

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

Question 34

What is the therapy for pyoderma?

Answer 34

Based on cytology while waiting for culture results and then based on susceptibility testing

Question 35

What skin lesions are seen with deep pyoderma?

Answer 35

Haemorrhagic crusts, draining tracts

Question 36

What are the underlying causes for acne in dogs and cats?

Answer 36

Often keratinisation defect underlying | Other underlying causes are demodecosis, dermatophytosis, FeLV, FIV and allergies in cats

Question 37

What animals does acne typically affect?

Answer 37

Short haired dog breeds as young animals or life long

Question 38

What is the therapy for acne?

Answer 38

Systemic treatment to get disease into remission and then topical treatments to maintain disease free state

Question 39

What are the characteristics of acral lick dermatitis?

Answer 39

Often large breed dogs with >95% positive bacterial culture

Question 40

How is acral lick dermatitis treated?

Answer 40

Long term antibiotics and prevent trauma

Question 41

What are the general treatment options for pyoderma?

Answer 41

Antibacterial medication, treatment/correction of underlying causes

Question 42

What are the special considerations for pyoderma therapy?

Answer 42

Recurrent, zoonotic implications, antimicrobial resistance

Question 43

How long do pyodermas need to be treated for?

Answer 43

Superficial - 3 weeks or 1 weeks beyond complete clinical cure Deep - 4-6 weeks for 2 weeks beyond complete clinical cure

Question 44

What is dermatophilosis?

Answer 44

Branching filamentous actinomycete that mainly affects ruminants and horses and varies in clinical presentations but can have a significant economic impact

Question 45

What are the diseases caused by dermatophilosis?

Answer 45

Fleece rot in sheep, mud fever in horses, rain scald in horses