Immune Mediated Skin Disorders Flashcards by Corinne Perra

How common are immune mediated skin disorders?

4% of canine skin disorders

1. 3% of feline skin disorders

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Generally what the the main diagnostic methods for immune-mediated skins disorders?

Histopathology
Multiple biopsy- most represented regions

Immunohistochemistry may be required

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Most common treatment for immune -mediated skin disorders

Immunosuppressive drugs

glucocorticoids
cyclosporine A

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What is pemphigus complex?

Vesiculobulbous to pustular disorders of the skin or mucous membranes - characterized by acantholyisis (loss of cohesion between keratinocytes)

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What is the difference between pemphigus erythematosus and pemphigus foliacious?

PE is the benign form of PF

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What can aggravate the pemphigus erythematous lesions

UV light

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Clinical signs of pemphigus erythematosus ?

Erythema, pustular dermatitis —> of the face and ears

Primary lesions are transient and lead to oozing crust, scale, alopecia, and erosion bordered by epidermal collerette

Nose typically depigments

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DDX for Erythema, pustular dermatitis —> of the face and ears

Primary lesions are transient and lead to oozing crust, scale, alopecia, and erosion bordered by epidermal collerette

Nose typically depigments

Pemphigus erythematous 
Facial pemphigus foliaceus
Discid lupus erythematosuss 
Systemic lupus erythematosus 
Dermatomyosititis 
Drug rxn 
Leishmaniasis 
Zinc responsive dermatitis 
Bacterial folliculitis 
Dermatophytosis 
Demodecosis

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Treatment for pemphigus erythematous

Sun avoidance

Topical glucocorticoids or cyclosporine

If not affective, add Vit E and give oral corticosteroids

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What is the most common immune-mediated skin condition?

Pemphigus foliacious

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What is the major antigen in pemphigus foliaceus?

Desmogelin 1 - adhesion molecule

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Mean onset of pemphigus foliaceous?

4yrs

—> spontaneous, secondary to drugs or chronic skin conditions

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Clinical signs of pemphigus foliaceous?

Pustular dermatitis
And crusting

Start of face and fears
Commonly involve feet, clawbed, footpad, and groin

Scale, alopecia, erosion, bordered by epidermal collerettes

Nasal depigmentation is common

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How would you confirm a suspected case of pemphigus foliaceous?

Histology and clincial signs

Skin biopsy- histopath wth immunofluorecence

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How would you treat pemphigus foliaceous?

Topical corticosteroids or cyclosporine

More extensive - pred at immunosuppressive does

Cats may require chlorambucil
Dog may require azathioprine

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What is the antigen in pemphigus vulgaris?

Desmoglein 3

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Clinical signs of pemphigus vulgaris

Vesiculobullous disease

Erosive to ulcerative disorder affecting oral cavity, mucocutaneous junction, or skin (75-90% have oral cavity lesions)

Cutaneous lesions are common in axillae and groin 
Ulcerative paronchyia (clawbeds involved)

Vesiculobullous disease

Erosive to ulcerative disorder affecting oral cavity, mucocutaneous junction, or skin

Ddx?

Pemphigus vulgaris 
Bulldogs pemphigoid
SLe 
Erythema mutliforma 
Toxic epidermal necrolysis 
Drug reaction 
Idiopathic ulceration 
Epitheliotrophic lymphoma

How do you treat pemphigus vulgaris?

Poor prognosis

High doses or oral prednisolone and azathioprine (or chlorambucil in cats)

What is bullous pemphigoid?

Very rare

Subepidermal vesicle formation - autoantibodies against the basal cell hemidemosomes of skin and mucosa

What drugs predispose to bullous pemphigoid?

Sulfonamide
Penicillin
Furosemide

Clinical signs of bullous pemphigoid ?

Cutaneous lesions in groin and axillae and nail beds — vesicle/bullae ulceration bordered by epidermal collerettes

Oral lesions

Diagnosis and treatment of bullous pemphigoid ?

History, clinical signs, skin biopsy, immunoflourescence

Immunosuppressive and immunomodulatory therapy

T cells are the predominate cells in lupus erythematosus.. ______Tcells in discoid lupus erythematosus and ________ Tcells in systemic lupus erythematous

Helper; suppressor

Dog breeds predisposed to Discoid lupus erythematosus?

``` Collies GSD Shetland Sheepdogs Siberian huskies Brittany spaniel German shorthaired pointers ```

Clinical signs in DLE?

Depigmentation, erythema and scaling of nose followed by erosions, ulceration and crusting

How can you confirm diagnosis of DLE??

History Clinical signs Histopath —> thickening of the basement membrane zone due to cellular infiltration ANA title and LE cell test may or may no be positive

Treatment of DLE?

Avoid sunlight, topical sunscreen Topical and systemic corticosteroids Vitamin E Immunomodulatory/immunosuppressive

What is the etiology of Systemic lupus erythematous?

Multifactorial | — genetics, immunological disorder, viral infection, hormonal disorder or UV light exposure

Fever, polyarthritis, proteinuria Skin lesions : alopecia, erythema, vesiculobullous to ulcerative Dx?

Systemic lupus erythematousus

How can you definitively diagnose SLE?

ANA test - but can be positive in 20% of dogs with infectious disease Multi systemic disease ( joint, skin, kidney, oral mucosa, hematopoietic system) Confirmatory histopath/ immunohistopathology of skin or oral mucosa

Treatment of SLE?

Glomerulonephritis - Mycophenolate Immunosuppressive therapy Immunomodulatory

How do cutaneous adverse drug reactions present?

Various - alopecia, purpura, poor wound healing, hyperpigmentation, pruritus - erythema multiforme, toxic epidermal necrolysis

What is erythema multiforme?

Multifactorial Ex Acute onset of erythematous macules or slightly elevated papules .. spread peripherally and clear centrally Urticaria plaques Vesicles or bullae Most lesions in ventrum, axillae, groin, and mucocutaneous junction

What will you see on histopath of erythema multiforme?

Hydropic degeneration in all levels of the epidermis

What are the causes of toxic epidermal necrolysis?

Drug | Flea dips

Presentation of toxic epidermal necrolysis ?

Pyrexia, anorexia, lethargy, and depression — multifactorial or generalized vesiculobullous disease

Diagnosis and treatment of toxic epidermal necrolysis

Skin biopsy - histopath —> full thickness epidermal necrolysis with minimal inflammation RX Underlying cause, systemic glucocorticoids Poor prognosis

Condition characterized by purpura wheals, edema, papules, plaques, nodules, alopecia, scarring, necroslsys and ulceration, often involving extremities

Vasculitis

Ex of vasculits?

Coexisting dz - infection, food hypersensitivity, inset bites, malignancies, lupus Idiopathic - 50% of cases

Breeds predisposed to vasculitis?

``` JRTS Scottish terriers GSD Greyhounds Dachshunds Rottweilers ```

Treatment of vasculitis?

Underlying dz Pentoxifylline Immunosuppressive/immunomodulatory drugs