Immune Mediated Skin Disorders Flashcards
How common are immune mediated skin disorders?
- 4% of canine skin disorders
1. 3% of feline skin disorders
Generally what the the main diagnostic methods for immune-mediated skins disorders?
Histopathology
Multiple biopsy- most represented regions
Immunohistochemistry may be required
Most common treatment for immune -mediated skin disorders
Immunosuppressive drugs
- glucocorticoids
- cyclosporine A
What is pemphigus complex?
Vesiculobulbous to pustular disorders of the skin or mucous membranes - characterized by acantholyisis (loss of cohesion between keratinocytes)
What is the difference between pemphigus erythematosus and pemphigus foliacious?
PE is the benign form of PF
What can aggravate the pemphigus erythematous lesions
UV light
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
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
Treatment for pemphigus erythematous
Sun avoidance
Topical glucocorticoids or cyclosporine
If not affective, add Vit E and give oral corticosteroids
What is the most common immune-mediated skin condition?
Pemphigus foliacious
What is the major antigen in pemphigus foliaceus?
Desmogelin 1 - adhesion molecule
Mean onset of pemphigus foliaceous?
4yrs
—> spontaneous, secondary to drugs or chronic skin conditions
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
How would you confirm a suspected case of pemphigus foliaceous?
Histology and clincial signs
Skin biopsy- histopath wth immunofluorecence
How would you treat pemphigus foliaceous?
Topical corticosteroids or cyclosporine
More extensive - pred at immunosuppressive does
Cats may require chlorambucil
Dog may require azathioprine
What is the antigen in pemphigus vulgaris?
Desmoglein 3
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
