10. Dermatology Flashcards
(195 cards)
What 3 things make an ectoparasite ‘important’
Clinical importance
Zoonotic importance
Economic importance
Which 3 types of parasites are found on the skin surface of the host
Fleas
Lice
Surface mites
Name the main surface mites found on the following species: cattle, sheep and horse
Cattle: Chorioptes bovis, Psoroptes
Sheep: Psoroptes ovis, Chorioptes bovis
Horse: Chorioptes equi, Psoroptes spp, Neotrombicula spp (harvest mite)
Name the main surface mites found on the following species: dogs/cats and rabbits (3 for each)
Dogs/cats: Ootodectes (ears), Cheyletiella (fur mite), Neotrombicula (harvest mite)
Rabbits: Cheyletiella, Leporacus gibbus, Psoroptes cuniculi (painful!!)
What 2 types of parasites are found below the skin surface
Burrowing mites
Demodex
What burrowing mites are found on the following species: dog, guinea pig and birds
Dog: Sarcoptes scabei
Guinea pig: Trixacarus
Birds: Knemidocoptes
Which 3 animals are demodex most likely to affect
Dog, hamster and sometimes cats
what is the importance of ticks
Affect many species
Vectors of disease
heavy infestation can be debilitating
Tick granuloma if mouthparts are retained
What is the importance of cutaneous myiasis
Sheep and rabbits
‘Blowfly strike’ is potentially fatal
Larvae feed on host tissue - major welfare problem
What 3 parasites are unlikely to be detected on the host (live In the environment)
Midges e.g. Culicoides spp. => sweet itch and vectors of disease
Nuisance flies => irritants, transmit disease and skin disease
Dermanyssus gallinae (Poultry red mite) => zoonotic
Name 3 places where bacteria can come from to cause skin disease - and give examples
Present on normal skin => ‘endogenous infection” - Dermatophilus congolensis
From the environment - Mycobacteria from soil
From other animals - Treponema funiculi infection from rabbit
State 6 reasons why bacterial skin disease occurs
- Normal protective mechanisms of the skin are compromised
- Mechanical damage
- Immunocompromise
- Defects in skin barrier function
- Changes to the skin microclimate e.g. warm/moist
- Dysbiosis - imbalance of microbes of the skin
3 portals of entry for bacteria to cause skin disease
Via follicles
Direct entry through damaged skin
Haematogenous spread (rare)
Name 3 reasons why bacterial skin disease manifestation varies
Depth of infection
Type of inflammatory response
Lesion distribution and severity
Name 5 clinical manifestations of bacterial skin disease
- Surface pyoderma
- Superficial pyoderma
- Deep pyoderma
- Bacterial granulomatous dermatitis
- Skin lesions secondary to systemic bacterial infections or infections with toxin-producing bacteria
What is surface pyoderma and give 3 examples
When bacteria multiply on skin surface only
Example: canine intertrigo (skin fold pyoderma), acute moist dermatitis, bacterial overgrowth syndrome
What is superficial pyoderma and give 6 examples
Infection within the epidermis or hair follicles
1. Greasy pig disease - Staphylococcus hyicus
2. Bacterial folliculitis
3. Impetigo
4. Exfoliative superficial pyoderma
5. Dermatophilosis (rain scald)
6. Fleece rot (Pseudomonas in sheep)
What is deep pyoderma and give 3 examples
Infection outside epidermis or hair follicle epithelium due to furunculosis, penetrating wounds or sepsis
1. Furunculosis
2. Abscesses
3. Cellulitis
What is bacterial granulomatous dermatitis and give 2 types and causative agents
Mycobacterial (pyo)granulomas caused by traumatic implantation of saprotrophic organisms
1. Non-filamenous bacterial granulomas e.g. staph, strep and actinobacillus => lesions contain small yellow granules
2. Filamenous bacterial granulomas e.g. Actinomyces, Nocardia => lesions are nodular masses which may involve bone
3 common diagnostics tests to diagnose bacterial skin disease
Cytology
Culture
Histopathology with skin biopsy
3 broad principals of treating bacterial skin disease
Kill the organism
Enhance body’s defences
Address underlying cause
Should you use systemic antibiotics for bacterial skin disease
Avoid if possible
Use topical antibacterials when possible
Systemic antibiotics should only be used for deep infections
3 classifications of dermatophytes
Geophilic - adapted for the environment
Zoophilic - adapted for mammals
Anthropophillic - adapted for man
Stages of infection of dermatophytosis
Skin micro trauma and damage
Inoculation and germination of infective arthroscopes
Germ tube penetrate stratum corner
Growth of fungal hyphae
Lesions