Allergy and immune- mediated skin disease

Question 1

State and briefly describe what causes allergic disease .

Answer 1

-genetics
-microbiome and antibiotics - microbial colonisation and exposure to the antigen early in life depend on if become tolerant to allergen
-exposure - intermitent or continuous
-skin damages and chemical exposure -environmental factors that disrupt the epithelial barrier of skin

Question 2

How do most allergic skin diseases present ?

Answer 2

-pruritis
-urticaria = hives ( horses )
-plaque formation

Question 3

Why does pruritis occur ?

Answer 3

-type 4 hypersensitivity -T helper 2 cells release proinflammatory cytokines like IL-31
- immune cells producing itch mediators e.g cytokines , chemokines

Question 4

Why does urticaria occur in horses ?

Answer 4

• type 1 hypersensitivity - mast cells and basophills release histamines - swelling and urticaria

Question 5

Why does plaque formation occur in allergic skin disease ?

Answer 5

-type 4 hypersensitivity - T helper 1 - release IFN y , interleukins cause cellular infiltration

Question 6

How does allergic skin disease usually present in dogs ?

Answer 6

pruritis with secondary infection, lesions and behavioural changes

Question 7

What are the different allergic skin diseases in dogs ? with examples of allergen

Answer 7

-food and environmental induced -atopic dermatitis (dust mites, pollens , food proteins )
-flea allergy ( saliva )
-contact allergy ( drugs )

Question 8

What are some presentations seen in food allergies and not environmental allergies in dogs ?

Answer 8

• malassezia increase
  -no seasonality
  -young onset
  -GI signs

Question 9

How do feline allergic skin diseases usually present ?

Answer 9

multiple ways
-self induced alopecia
-head/neck pruritis
-ulcers / plaque
-millary dermatitis - scabs
-lip lesions from excess licking

Question 10

What are the different allergic skin diseases in cats ? with examples of allergen

Answer 10

-feline atopic skin syndrome (house dust mites , pollen ,mould )
-flea allergy (saliva )
-insect and mite hypersensitivity (mosquito saliva , otodectes antigens )
-food allergy ( food proteins )

Question 11

What are the different allergic skin diseases in horses ? with examples of allergen

Answer 11

-insect bite hypersensitivity ( biting flies e.g culicoides )
- equine atopic skin disease ( stable mites , pollens , food allergy rarely reported hard to diagnose )
-contact allergy - ( tack - nickel , dyes )

Question 12

What do horses commonly present with with allergic skin diseases ?

Answer 12

urticaria and pruritis with secondary infection and behavioural changes