Lecture 13 3/24/25 Flashcards
How do autoimmune vs immune-mediated conditions compare?
-both categories see the immune system mistakenly attacking bodily tissues
-autoimmune conditions have identified target antigens
-immune-mediated conditions do not have specific identified target antigens
What are the layers of the epidermis?
-stratum corneum
-stratum granulosum
-stratum spinosum
-stratum basale
Where are melanocytes found?
stratum basale of the epidermis
Which structures are found n the dermis?
-sebaceous glands
-hair follicles
Which structure is found in the hypodermis?
cutaneous plexus, containing artery and vein
What is the purpose of desmosomes?
to link keratinocyte to keratinocyte
What is the purpose of hemidesmosomes and anchoring fibers?
to link epidermis and dermis
What is the pathomechanism of pemphigus complex?
breakdown of the epidermal intercellular desmosomal connections
What finding is seen in histopath. in pemphigus complex?
separation of keratinocytes in the stratum granulosum
Which superficial lesions are seen in pemphigus complex?
-pustule
-crust
-erosion
What are the variants of pemphigus?
-pemphigus foliaceus: most common
-pemphigus vulgaris: severe clinical signs and mucosal involvement
-pemphigus erythematosus: PF + lupus histologically
-drug-induced PF: triggered by flea meds
Which lesions are seen in pemphigus foliaceous in dogs?
-pustules**
-yellow crusts**
-erosion
*may be pruritic
What is the distribution of lesions in pemphigus foliaceous in dogs?
-bilateral symmetry
-nasal planum
-nasal bridge
-periocular area
-concave aspect of ears
-footpads
Which lesions are seen in pemphigus foliaceous in cats?
-crusts
-pustules that rupture easily
-erosion
*may be pruritic
What is the distribution of lesions in pemphigus foliaceous in cats?
-bilateral symmetry
-face
-ears
-claw folds
-footpads
-around nipples
What is the pathomechanism of drug-induced PF?
PF triggered by flea medications and possibly shampoo
What is the clinical presentation of drug-induced PF?
-same lesions as regular PF
-lesions begin at the site of medication application
-lesions may expand to the typical PF distribution
How is pemphigus complex diagnosed?
-cytology
-histopathology
What is seen on cytology that allows for pemphigus complex diagnosis?
-acantholytic cells and neutrophils
-no bacteria (rules out superficial pyoderma)
What is the treatment for pemphigus complex?
lifelong immunosuppression and treatment of relapses
What is seen when bacteria causes acantholysis?
-pustule lesions
-acantholytic cells + neutrophils with bacteria
What is the pathomechanism of autoimmune subepidermal blistering diseases?
autoantibodies against components of the basement membrane
What ae the deeper lesions seen in autoimmune subepidermal blistering diseases?
-vesicles/bullae with fluid only; no pus
-deep erosions/ulcers
What are the types of autoimmune subepidermal blistering diseases?
-mucous membrane pemphigoid: most common, seen at the mucosa of GSDs
-bullous pemphigoid: occurs on haired skin
epidermolysis bullosa acquisita: seen on the footpads, ears, and oral cavity of young great danes
How are autoimmune subepidermal blistering diseases diagnosed?
-histopath. with subepidermal clefting
-signalment and clinical distribution to determine variant
What is the treatment for autoimmune subepidermal blistering diseases?
immunosuppression
What are the categories of lupus-specific skin disease/cutaneous lupus erythematosus?
-subacute CLE
-chronic CLE
What is the subtype of subacute CLE?
vesicular CLE
What are the subtypes of chronic CLE?
-exfoliative CLE
-mucocutaneous LE
-discoid LE; facial or generalized
What are the lupus-nonspecific skin diseases?
-vasculitis
-autoimmune BM disease
What is the pathomechanism of cutaneous lupus erythematosus?
-UV-induced skin injury
-autoantigen stimulation
-dysregulation in cell death and clearance processes of basal cells by cytotoxic T cells
Which lesions are seen in cutaneous lupus erythematosus?
-ulcer
-depigmentation
-scarring
What are the characteristics of vesicular CLE?
-seen in shelties and collies
-found on unhaired skin
What are the characteristics of facial-dominant discoid LE?
-most common
-seen in GSDs
-only occurs on the nose
What are the characteristics of generalized DLE?
-annular to polycyclic lesions
-found on haired skin
Where is mucocutaneous CLE found?
lips and genitalia
What are the characteristics of exfoliative CLE?
-autosomal recessive disorder
-seen in german short-haired pointers
How is CLE diagnosed?
-histopath. with lupus patterns
-signalment + clinical distribution to determine variant
What are the lupus patterns seen on histopath?
-lymphocyte-rich interface dermatitis
-basal keratinocyte apoptosis
-pigmentary incontinence
-lupus band/deposition of immunoglobulins
What is the treatment for CLE?
-avoidance of UV exposure
-topical and systemic immunosuppression
