Vesiculobullous Diseases Flashcards
what are VB diseases
group of skin + mucous membrane disorders that cause fluid filled blisters and lesions
difference between vesicles and bullae
vesicles - <5mm visible fluid within/beneath epithelium
bullae - >5mm visible fluid within/beneath epithelium
oral mucosa is made up of “EBL”
describe this and its components
EPITHELIUM - keratinocytes, stratified squamous
BASEMENT MEMBRANE - non-cellular, connects epithelium and lamina propria
LAMINA PROPRIA - collagen, fibroblasts, nerves, blood vessels
desmosomes function
joins keratinocytes
junction of epithelial cells
hemidesmosomes function
joints basal keratinocytes to basemembrane
half size
describe direct immunofluorescence DIF
tissue biopsy
antibody bound to fluorophore specific to IgG/A + C3 bound to tissue
UV microscope, fluorescence at binding areas
describe indirect immunofluorescence
blood sample
contains primary disease antibody, incubated with monkey oesophagus
addition of secondary antibody and fluorophore
antibodies shown in tissue if present
less sensitive in MMP
mucous membrane pemphigoid
appearance
cause
pathogenesis
diagnosis
oral vesicles/blisters turning ulcers, desquamative gingivitis
ocular, conjunctive scarring, anogenital, scalp, nasal
scarring, robust
unknown, autoimmune, genetic, 50-60f
antibody IgG targets basement membrane (hemi)
sub epithelial splitting
biopsy for H+E staining, DIF
blood sample for indirect [less sensitive]
management of MMP
MDT - OM, ophthalmology, gynae, derm
reassure, education, OH, manage pain, diet
benzydamine mw
betamethasone mw
clobetasol tray v splint
intralesion triamcinolone
systemic = prednisolone pulsed 1-2 weeks, damson, doxycycline, rituximab
pemphigus vulgaris
appearance
cause
pathogenesis
diagnosis
blisters, erosions, ulcers, desquamative, ocular/anogenital/skin
painful, systemically unwell, potentially lethal
female, autoimmune
IgG directed against desmosomes, loss of cell-cell contact, acantholysis
intraepithelial split
Nikolsky’s sign - rubbing mucosa induces bullae
biopsy - H+E intra, DIF shows chickenwire deposition of IgG + C3
indirect - more sensitive
management of PV
MDT, maybe inpatient for IV fluids, 2nd infection, analgesia
1st phase =
remission - prednisolone +/- bone protection, gastric protection bisphosphonates, vitamin D, Azathioprine, MMF, rutiximab
2nd phase =
gradual steroid withdrawal, regular monitoring, topical steroids, benztdamine, excellent OH
what is the name of the malignant disorder which appears as pemphigus
neoplastic pemphigus
due to underlying malignancy
immune system disarray
severe mucosal + skin involvement
high mortality
which condition is Nikolsky sign positive
pemphigus vulgaris
when rubbing mucosa, induces bullae
what VB conditions may present as ulceration, blistering and crusting of mucosa/lips with flu prodrome
as a result of hypersensitivity, infection, drugs, vaccines
describe pathogenesis
diagnosis
and management
erythema multiforme
release of cytokines from CD4 cells, amplified immune response, CD8+ T cell attack keratinocytes causing apoptosis and necrosis
biopsy - intra+sub splitting
DIF - non-specific
HSV serology/throat swab for mycoplasma pneumonia
MDT, consider inpatient, fluids, feeding, analgesia
stop precipitating meds, steroids
25% recurrence
consider immunosuppression via Aza, MMF
acyclovir due to HSV
what medications could cause erythema multiforme
allopurinol, carbamazepine, NSAIDs, phenytoin
MMP + linear IgA disease present similarly
on DIF they both have sub epithelial splits
how to differentiate
MMP - linear deposits of IgG along base membrane
Linear - linear IgA deposits along basement membrane
pt with HIV presents with widespread skin blistering, oral, pharyngeal, nasal, conjunctival
black lips
just started new meds
what is ur diagnosis
Steven-johnson / toxic epidermal necrolysis
hypersensitivity, genetic, 100x more likely in HIV due to CD4 depletion
antigens via meds, dysregulated immune res[pnse, CD8 cells/macrophages into epithelium, granulysin release, apoptosis and necrosis of granulocytes
biopsy shows detachment from dermis
URGENT assessment in special care, ABCDE
stop causative agent
MDT
