Blistering Diseases Flashcards
What are the different forms and presentations of pemphigoid?
Bullous pemphigoid- affects the skin
Mucous membrane pemphigoid- affects mucous membranes (eyes, genitals, oral)
Cicatritial pemphigoid- affecting the mucosa but with scarring
How does pemphigoid occur?
It is a sub epithelial antibody attack
The antibodies cause separation of the epithelium at the basement membrane from the connective tissue and the full thickness of the epithelium is released with fluid inflammatory exudate filling the space between the epidermis and connective tissue.
The blisters are thick and tend to persist for some time as the fluid can come from connective tissue
There may be some immunological damage in this area there may be leakage o the red blood cells in the fluid the blisters can appear clear or blood filled
Where should you take a biopsy from in suspected pemphigoid?
Take from the perilesional area rather than the blister itself
What does the histopathology look like in pemphigoid?
There is a clear junction at the epithelial/connective tissue due to the sub epithelial split
Hemi-desmosomes involved at the basement membrane
–attack of circulating antibody is to the hemi-desmosomes and this allows the desmosomes to lose its attachment and the epithelium to split from the connective tissue
What does direct immunofluorescence detect in pemphigoid?
Produces a linear staining along the basement membrane
C3 and IgG detected in standard pemphigoid
IgA occasionally found
Most useful test in diagnosing
How do you treat pemphigoid?
Steroids
Immune modulating drugs- azathioprine, mycophenolate (try to prevent the antibody generation)
What is the commonest form of pemphigus?
Pemphigus vulgaris
What is pemphigus?
What is involved at the epithelial level?
Immune mediated antibody directed disease
Desmosomes are involved in this not hemidesmosomes, lose adhesion to each other and allow intraepithelial bullae to form where the cells gradually drift away, initially thinning but then losing epithelium completely
What does a patient with pemphigus present with?
Presents with mucosal erosion and mucosal surface loss as the cells are gradually lost from the surface of epithelium from the disease
Skin and mucosal (often first) lesions
forms blisters that burst and then spread (rare to see an intact bullae)
What do you see histopathologically in pemphigus?
A shedding of the epithelial layer
Supra-basal as you can see basal cells still attached to basement membrane and this split has occurred above this point
Tzank cells are characteristic cells seen in pemphigus
What is found in immunofluorescence in pemphigus?
Basket-weave pattern staining around each of the epithelial cells
–because the antibody is attacking desmosomes which are present on many surfaces of the epithelial cells that all around the cells is displaying antibody binding
C3 and IgG found in pemphigus vulgaris
What is used to treat pemphigus?
High doses of steroids(prednisolone) and immunosuppressants (mycophenolate)
Biologics can also be used
