Approach to pruritus

Question 1

List 4 clinical presentations of pruritus

Answer 1

Scratching, chewing
Licking feet (dogs)
Feather-plucking (birds)
Overgrooming (=‘self-induced alopecia’) (cats)

Question 2

List the 4 feline reaction patterns

Answer 2

Self-induced alopecia (SIA)
Face, head and neck pruritus (FHN)
Miliary dermatitis (MD)
Eosinophilic granuloma complex (EGC)

often more than one pattern present

Question 3

Describe self-induced alopecia (feline reaction pattern)

Answer 3

Bilaterally symmetrical alopecia in areas that cat can reach with tongue
hair often stubbly

Question 4

Describe how to diagnose self induced alopecia

Answer 4

Trichogram- look for broken hairs

Question 4

Describe Face, head and neck pruritus (feline reaction pattern)

Answer 4

36% causes due to ectoparasites- especially fleas

Question 5

Describe Miliary dermatitis (feline reaction pattern)

Answer 5

Papulocrustous lesions (can’t see unless clip hair) , especially on dorsum

Question 6

List the 3 types of Eosinophilic granuloma complex (feline reaction pattern)

Answer 6

1. eosinophillic grauloma
   2,. eosinophillic plaque
2. Indolent ulcer (‘Rodent ulcer’)

Question 7

Describe Eosinophilic granuloma

Answer 7

Well-demarcated, solid, raised, yellow to pink plaques/nodules
+/- eroded or ulcerated surface
+/- crust

Any site but especially caudal thighs (linear), oral cavity, feet, chin

Question 8

Describe eosinophilic plaque

Answer 8

Raised, flat-topped erythematous plaques
Usually ulcerated/eroded and pruritic
Usually ventral abdomen/caudal thigh

Question 9

Decsribe Indolent ulcer (‘Rodent ulcer’)

Answer 9

Erosive/ulcerated lesion on mucocutaneous junction of upper lips

Unilateral/bilateral

Rarely painful or pruritic

Question 10

List 3 differentials which should always be condisered with all feline reaction patterns

Answer 10

flea allergic dermatitis
feline food allergy
feline atopic skin syndrome

these are the most common causes of feline reaction patterns

Question 11

What are the 3 main groups of causes for pruritus

Answer 11

Allergy
ectoparasites
infections

Question 12

when does environmental allergic dermatitis generally start

Answer 12

6m- 3 yr

Question 13

Why may endocrinopathies present as pruritus

Answer 13

Secondary microbial infection due to immunocompromise

Question 14

If you see: Dog with dull coat, lethargy and bradycardia
what should you suspect

Answer 14

hypothyroidism

Question 15

If you see: Dog with diffuse thinning of coat, PUPD, polyphagia
what should you suspect

Answer 15

hyperadrenocorticism

Question 16

What is pustules most common caused by

Answer 16

superficial pyoderma (staphylococcal folliculitis)

Question 17

If you see Epidermal collarettes, crusts
what is it most commonly caused by

Answer 17

superficial pyoderma
occasionally- Pemphigus F

Question 17

After treatment of ectoparasites and infection the pruitus resolves fully ….

Answer 17

this implies non-pruritic cause - e.g. immunosuppressive disease including endocrinopathies
OR
ectoparasites, if not previously on good ectoparasite control

Question 18

After treatment of ectoparasites and infection the pruitus remains…..

Answer 18

implies other pruritic underlying cause - usually atopic dermatitis (environmental or food-induced)

Question 19

Describe how to distinguish between environmental and food-induced atopic dermatitis

Answer 19

exclusion diet trial- 8 weeks minimum
but also give prednisolone or oclacitinib for first 2-3 weeks then see if pruritus reoccurs

Question 20

How do you reach a environmental atopic dermatitis diagnosis

Answer 20

exclusion
there are tests but these are not used to diagnose

Question 21

You suspect a 2yo French bulldog with generalised pruritus to be suffering from canine atopic dermatitis. You have found no evidence of microbes or ectoparasites on investigation. What is your next step?

Answer 21

Treat this dog and in-contacts with an isoxazoline, and use an environmental flea spray