Dermatology allergic and autoimmune

Question 1

Why are cats with fleas often the cause of dogs getting FAD

Answer 1

Because they can tolerate large burdens of fleas without showing signs

Question 2

Signs of flea allergic dermatitis in dogs

Answer 2

Pruritis of caudal dorsum, medial thights

Question 3

Signs of flea allergic dermatitis in cats

Answer 3

Pruritic miliary dermatitis of crusted papules, alopexia, head and neck greatly affected

Question 4

What type of antibodies are associated wtih atopic dermatitis

Answer 4

IgE

Question 5

Favrot’s criteria for atopic dermatitis

Answer 5

i) Early onset <3 years of age
ii) Indoor lifestyle
iii) Glucocorticoid responsive
iv) Pruritus sine materia at onset i.e itchy but nothing to see when it started  THEN get changed associated with pruritis and scratching
v) Affected feet and/or ears
vi) Non-affected ear margins and/or dorsal lumbar [distinguish from FAD]

Question 6

What must we remember to do in relatino to other diseases and Favrot’s criteria for atopic dermatitis

Answer 6

Treat other issues that are superimposed on top/mimic this condition e.g fleas, pyoderma
Then get a better specificity of the criteria

Question 7

Infestation with what might give positive allergy testing to house dustmite

Answer 7

Sarcoptes scabei

Question 8

How is atopic dermatitis treated basic

Answer 8

Steroids; should respond fully!! if not then suggests something else going on

Question 9

How does intradermal skin testing work

Answer 9

Injecting antigen solution into skin; including positive (histamine) and negative control
Compare wheal size with positive control

Get a reaction where there is IgE cross linking and mast cell degranulatoin

Question 10

What is atopic-like dermatitis

Answer 10

Where we have all the signs of atopic dermatitic but no evidence of an IgE response on intradermal skin testing or in-vitro allergen testing

Question 11

Treatment options fo atopic dermatitis

Answer 11

Glucocorticoids
Calcineurin inhibitors (tacrolimus, ciclosporin)
Could do allergen specific immunotherapy
Shampoos
Janus kinase inhibitors e.g oclacitinib
Lokivetmab m-Ab against IL31 (cytopoint)

Question 12

What is lokivetmab directed against

Answer 12

IL-31
Licensed for use in atopic dermatitis

Question 13

When to go for allergen-specific immunotherapy and what are the success rates

Answer 13

Do it is the intradermal skin test allergy results make sense with lifestyle of animal etc

33% do very well, 33% have some improvement,, 33% no better

Question 14

What is food induced atopic dermatitis/cutaneous adverse food reactions

Answer 14

= clinically very similar to atopic dermatitis but the reaction is triggered by food not external allergens

Question 15

What is the classic signs of food induced atopic dermatitis

Answer 15

Any age
Classically non-seasonal pruritis
May see GI signs

Question 16

What must we remember about in vitro allergen testing and food-induced atopic dermatitis

Answer 16

It is NOT reliable for this

Question 17

How can we diagnose/treat food induced atopic dermatitis

Answer 17

strict diet trial for minimum of 1-2 months

Question 18

What is feline atopic syndrome

Answer 18

variety of allergic diseases that may be associated with a hypersensitivity to environmental allergens and foods +/- FAD

Involves allergic dermatitis, asthma, GI disease

Question 19

What cutaneous reaction patterns might a cat with feline atopic syndrome present with

Answer 19

1) Head and neck pruritis
2) Self-induced alopecia/hypotrichosis
3) Miliary dermatitis
4) Eosinophilic granuloma complex

Question 20

Treatment for feline atopic syndrome

Answer 20

Systemic glucocorticoids and cyclosporins
Could try off licence oclacinitib

Question 21

Options to deal with feline food allergy

Answer 21

• Can try hydrolysed diets
• Novel protein

Question 22

WHat medication can cause contact dermatitis in cats

Answer 22

Otic medication

Question 23

How common is allergic contact dermatitis in cats

Answer 23

Rare
Gets overdiagnosed

Question 24

What drug can we use to spare steroids in feline atopic skin syndrome

Answer 24

Cyclosporine

Question 25

Skin histopath with mast cells, lymphocytes and eosinophils may be indicative of what on a cat

Answer 25

Feline atopic skin syndrome

Question 26

What drugs can we use to treat auto-immune skin disease

Answer 26

Immunsuppressive: Prednisolone, cyclosporine, azathioprine, chlorambucil, mycophenolate mofetil Immunomodulating: tetracycline, niacinamide Topical agent: tacrolimus

Question 27

What topical drug might we use for autoimmune skin disease

Answer 27

Tacrolimus

Question 28

WHat immunosuppressive drug should we not give to cats

Answer 28

Azathioprine

Question 29

What is the new classification of autoimmune skin disease and which things fit under these groups

Answer 29

Antibody mediated AISDs: pemphigus/pemphigoid Lymphocyte mediated AISDs: CLE

Question 30

What are the three autoimmune diseases in the pemphigus group

Answer 30

Pemphigus foliaceous Pemphigus erythematous Pemphigus vulgaris

Question 31

Signs of pemphigus foliacus

Answer 31

Pustules; Face and feet often worst affected + nail beds in cats; pustules etc May see pyrexia, lymphadenopathy due to immune system activation

Question 32

What is the aetiology of pemphigus foliaceus

Answer 32

Antibodies formed against desmosomes in stratum spinosum causing decoalescence to form pustules

Question 33

Target antigens in pemphigus group dseases

Answer 33

Desmosome components which hold epidermal cells together anti-desmogleins/desmo-collins

Question 34

Which breeds are at increased risk of pemphigus foliaceous

Answer 34

Akita Chow

Question 35

What is the Tzanck test

Answer 35

Where a pustule is ruptured to do cytology

Question 36

What might we see on cytology of a pustules with P foliaceous

Answer 36

Mature hypersegmented neutrophils with acantholytic cells (large and basophilic) which are from the stratum spinosum

Question 37

Which epidermis layer is targeted in P foliaceous

Answer 37

Stratum spinosum

Question 38

What medication can trigger p foliaceous in dogs

Answer 38

Spot ons

Question 39

What does P erythematous look like and which animals are predisposed

Answer 39

Dogs, very rare in cats; GSDs, collies, shelties Pupules/lesions limited to bridge of nose, eyes, ear pinnae

Question 40

What is the most severe form of pemphigus

Answer 40

P vulgaris

Question 41

How does pemphigus vulgaris PRESENT

Answer 41

Skin on axilla/ingiunum affected + mucocutaneous junctions, and MMs Get haemorrhagic ulcerative crusting Also see pyrexia, depression, halitosis

Question 42

What happens in AISBD (bullous pemphigoid)

Answer 42

Formation of auto-antibodies against basement membrane causing separation of the dermis from the epidermis and bullae formation Affects skin, mucocutaenous junctions and MMs; ulcerative

Question 43

What other auto-immune disease does AISBD (bullous pemphigoid) resemble and how do we tell them apart

Answer 43

P vulgaris Use biopsies

Question 44

Treating AISBD

Answer 44

High dose preds + cyclosprone Can add other immunosuppressives in if needing to reduce steroids

Question 45

What is cutaneous lupus erythematosus

Answer 45

Lymphocyte rich dermatitis with prominent basal keratinocyte death

Question 46

What is the most common form of cutaneous lupus erythematosus

Answer 46

Discoid lupus erythematosus

Question 47

Signs of discoid lupus erythematosus

Answer 47

Nasal depigmentation, erythema, ulceration

Question 48

What might we need biopsy to distinguish discoid lupus erythematosus from

Answer 48

Epitheliotrophic T cell lymphoma

Question 49

Treatment of discoid lupus erythematosus

Answer 49

Avoid sunlight If severe use immunosuppression Try topical agents e.g tacrolimus Can use immunomodulating effects of niacinamide if less severe

Question 50

What does vesicular lupus erythematosus look like

Answer 50

Axillary and inguinal ulceration, alopecia and erytehma Rare

Question 51

Diagnosis of systemic lupus erythamtosus

Answer 51

Anti-nuclear antibody positive + anti-histone antibody positive Biopsy of skin lesions can be helpful if they are rpesent

Question 52

What signs might we see with systemic lupus erythematosus

Answer 52

half have skin lesions Most have joint disease Half have haematological changes due to bone marrow being targeted e.g anaemia, thrombocytopaenia, proteinuria Some also show glomerulonephritis; would get marked proteinuria

Question 53

How many biopsies should we take when assessing skin disease

Answer 53

Up to 6 probably; 1 not enough

Question 54

Histology of atopic dermatitis

Answer 54

Superficial perivascular dermatitis with mast cells, eosinophils, lymphocytes and histiocytes

Question 55

What type of hypersensitivity is allergic contact dermatitis

Answer 55

Type IV hypersensitvity mediated by cytotoxic CD8+ T lymphocytes

Question 56

How is atopic dermatitis mediated

Answer 56

IgE response to environmental allergens Because there is inflammation and IL4 production whcih causes shift from IgM to IgE

Question 57

Histology of flea bite hypersensitity

Answer 57

Superficial perivascular eosinophilic, lymphocytic, histiocytic dermatitis

Question 58

What is the target of pemphigus foliacus vs vulgaris (specifically)

Answer 58

P foliacus: desmoglein 1 P vulgaris: desmoglein 3; more present in mucocutnaeous junctions hence the clinical signs here

Question 59

Histology of pemphigus

Answer 59

 Superficial dermatitis with eosinophils, neutrophils, lymphocytes

Question 60

Histology of discous lupus erythematosus

Answer 60

basal cell degeneration, infiltration of lymphocytes and plasma cells at the epidermal dermal interface (becomes very thick), with pigmentary incontinence (because melanocytes are in stratum basale and get damaged so release melanin and then macrophages phagocytose this) and crusting

Question 61

Which dogs get bullous pemphigois most

Answer 61

Collies

Question 62

HIstology of bullous pemphigoid

Answer 62

vesicles or bullae within basement membranes (between PM and stratum basale), eosinophils On immunofluorescence see IgG etc at dermoepidermal junction

Question 63

What immunosuppressive drugs could we use for autoimmune conditions

Answer 63

Prednisolone Cyclosporine Azathioprine (not in cats) Mycophenolate mofetil Chlorambucil