Pruritic Animal Flashcards
Signs of Pruritus
- Scratching, chewing
- Licking feet
○ Dogs - Overgrooming
○ Cats - Stamping
○ Horses - Barbering - plucking their fur and whiskers
○ Small mammals
Common Causes of pruritus
Hypersensitivities
Parasites
Microbial infections
Neoplasia
Autoimmune disease
Hypersensitivity causes of pruritus
○ Environmental atopy
○ Food-induced atopy
○ Parasite induced hypersensitivities
○ Microbial hypersensitivities
○ Drug reactions
○ Contact allergy
Parasitic causes of pruritus
Insects
* Flies
* Lice
* Fleas
Mites
Endoparasites
* Hookworm in dogs
* Oxyuris in horses
Microbial causes of pruritus
Bacterial pyoderma
Malassezia dermatitis
Dermatophytosis
How to make a ranked differentials list
Signalment
History
Clinical exam
Signalment considerations
Age
Sex
Species
Breed
Species considerations
○ Diseases affect different species with different frequency
○ E.g. environmental atopy not a consideration for farm animals but ectoparasitic disease is very important
Age considerations
○ Consider not only age now, but age of ONSET of first signs of pruritus (often v minor)
Many cases will have started several years ago!
○ Most parasites:
Any age
Except Demodex usually old/young animals)
○ Environmental atopy (dog, cat, horse):
Commonly older juvenile, young adult
○ Food-induced atopy (dog, cat):
Onset any age, but especially if young
○ Older animals with no prior skin disease consider
Neoplasia
Microbial infection, secondary to immunosuppression/ endocrinopathy
Sex considerations
Sertoli cell tumour -> secondary pyoderma
History considerations
- Animal background
- Details of husbandry
○ E.g. housing, bedding, diet) - Routine medical care and when administered
- History of contagion/zoonosis
- Details of skin condition
○ Age of onset/duration
○ Initial clinical signs/progression
○ Seasonality - Evidence of systemic disease etc
Diagnostic tests for parasites
Coat brushing
Skin scrapes
Trichograms
Impression smears
Acetate tape strips
Diagnostic tests for microbes
Acetate tape strips
Impression smears
Wood’s lamp
Dermatophyte direct microscopy/culture
What to do if confirmed parasites as cause?
- Treat as appropriate
- If parasites +ve
○ Treat to eliminate them - If parasites –ve, but suspicious from history
○ Trial treatment
○ Esp fleas, Sarcoptes, Cheyletiella in dog/cat - If Bacterial/Malassezia
○ Treat if confirmed
○ Usually a secondary problem
○ May be masking underlying problem
What should you do if pruritus persists after microbial/actoparasite treatment?
Consider hypersenitvities
Autoimmune diseases
Neoplasia
