9- Microbial causes of skin disease: bacterial

Question 1

Give 2 reasons why bacterial skin disease occurs

Answer 1

Mechanical damage to the skin

Immunocomprimise

Defects in skin barrier function

Changes to skin microclimate

Dysbiosis

Question 2

Define Dysbiosis

Answer 2

imbalance of the microbes in our skins normal by microbiome that tips over ultimately into clinical disease.

Question 3

Name the 3 portals of entry for bacteria into the skin

Answer 3

Via follicles
Via damaged skin
Haematogenous spread (rare)

Question 4

What does disease manifestation depend on in bacterial infections

Answer 4

Depends on Organism and its virulence factors, predisposing/coexisting factors, host immune response

Question 5

Name the 5 common clinical manifestations of bacterial skin disease

Answer 5

Surface pyoderma
Superficial pyoderma
Deep pyoderma
Bacterial granulomatous dermaitits
Skin lesions secondary to systemic bacterial inf. or infection with toxin producing bacteria

Question 6

What is surface pyoderma

Answer 6

Where bacteria multiply on the skin surface only

Question 7

Give an example of surface pyoderma

Answer 7

Canine intertrigo (skin fold)
Acute moist dermatitis (hotspots)
Bacterial overgrowth syndrome

Question 8

Superficial pyoderma is an infection within what?

Answer 8

Epidermis +/- hair follicle

Question 9

What clinical signs are generally associated with superficial pyodermas

Answer 9

–>papules/pustules –> crust, epidermal collarettes/scale, follicular plugs, alopecia

Question 10

What is impetigo

Answer 10

interfollicular infection of the epidermis (between follicles)

Question 11

What is an Exfoliative superficial pyoderma

Answer 11

infection between layers of stratum corneum

Question 12

A deep pyoderma is an infection of what

Answer 12

Infection outside epidermis or hair follicle epithelium

Question 13

What are deep pyodermas generally due to

Answer 13

rupture of hair follicle wall (furunculosis)
penetrating wounds
haematogenous spread (sepsis)

Question 14

What is deep pyoderma normally associated with?

Answer 14

Thickening of the skin, nodules and draining sinuses

Abscess
Cellultis
Furunculosis

Question 15

What is cellulitis

Answer 15

suppurative inflammation of the deep subcutaneous tissue

Question 16

What is bacteria granulomatous dermatitis caused by

Answer 16

Traumatic implantation of saprophytic organism

Question 17

How are bacterial skin diseases generally diagnosed

Answer 17

Cytology
Culture
Histopathology- skin biopsy

Question 18

T/F You always need to give antibiotics for an abscess

Answer 18

False- lance and drain
Antibiotics only indicated if pyrexia/ cellultis is involved
except caseous pus of rabbit abscess- requires surgical intervention

Question 19

List the broad principles of treating bacterial skin diseases

Answer 19

Kill the organism
Enhance body’s defences where possible
Address underlying cause where possible

Question 20

When should antibiotics be used when treating a bacterial skin disease

Answer 20

Avoid antibiotics and use topical antibacterials wherever possible
Systemic antibiotics needed for deep infections (base on culture and susceptibility test)

Question 21

describe acute moist dermatitis

Answer 21

acute lesion caused by skin self-trauma
is a surface pyoderma