Vesiculobullous Diseases Flashcards
Why is it often diseases are seen to affect both the skin and the oral mucosa
This is because embryologically the oral mucosa develops from the same precursor as the skin, they share many common antibodies and epitopes, so when antigens and diseases affect one it tends to affect both
Why do vesicle/ blisters form in immunological skin disease?
Auto-antibody attack on skin components causing loss of cell- cell adhesion
Split forms in the skin which fills with inflammatory exudate forming a small blister
What is the difference between a vesicle and a blister
The size of the lesion
Vesicles are typically 1-2mm larger and blisters are larger
Discuss desmosome/ hemidesmosome attachment in relation to immunobullous disease and how blisters/vesicles happen
The desmisomes or hemidesmosomes attach the epithelial cells to each other, to the basement membrane and to the protein desmoglein
This protein is the target site for many antibodies involved in immunobullous diseases and the way this is bound to the antibody causes there to be adhesion lost between the desmosomes allowing the cell to split
How can the process of the desomosome split be seen?
Direct immunofluresence
Applying tests to biopsy site which are looking for evidence of the antibody within the skin tissues.
How does direct immunofluroescnce work
Antibody has been in circulation binding to the tissue causing disease.
By manufacturing another antibody which has got a fluroscceine marker on it, this second antibody will bind to the primary antibody so that when the tissue is examined with lighting the fluorescence will be demonstrated showing where antibody is found in the tissue
If a sample taken from a biopsy from immunoflorsence is being transported what must you be wary of?
It must not be put in a FORMALIN containing transport medium as this will cause the binding site to be lost
Must be transported fresh to lab and processed quickly
What is indirect immunofluoresnce
In this case the circulating antibody is not yet bound to the tissue
Detected by immunofluorescene from a PLASMA sample
Indirect immunoflurescence is not always useful for diagnosis but what can it be useful. For
Often good for monitoring disease activity
What is erythema multiformE?
Spectrum disorder of immunogenic related skin and mucosa ulceration
How does erythema multiforme happen?
Immune mediated hypersensitivity reaction
Antigens and antibodies combine within the circulation and this large complex is unable to pass within the capillaries it becomes wedged and activates compliment within the tissues causing a peri vascular inflammatory response
When this is signifant the patient will get blistering or inflammation of the tissue
What is erythema multiforme called in its most extreme form
Steven Johnsons syndrome
Severe multi system involvement
What is erythema Multiforme called in its most extreme form
Steven Johnson’s syndrome
Severe multusstem involvemeeent
What are the major attacks in erythema multiforme though to be triggered by
Recurrent hermetic lesions or other infections e.g. mycoplasma
What is the most efffective Treatment from erythema multiforme
High dose prednisolone to suppress the antibody antigen reaction and the compliment activation in the tissues
Why is hydration so important in patients with erythema multiforme
If patients present late the key thing is hydration as most of these patients present in hospital admission because mouth and pharynx are too sore for fluid intake
What is some typical presentation of erythema multiforme
Crusted haemorrhagic Bullae are often seen on the lips, the oral mucosa, eyes and genital skin area.
Target lesions sometimes occur on the skin
In severe illness there may be febrile illness or hospital. Admission
What can be prescribed propholactivly for erythema multiforme if recurrent probelms
Acicolvir 400mg 2x daily
To prevent recurrence even in the absence of preceding herpetic infection
What is the most common oral blistering condition
Angina bullosa haemorrhagica
‘’Blood blisters ‘’n the mouth
What are the most commonly affected sites in angina bullosa haemorrhagica
The hard and soft palate
They suddenly appear( rapid onset) and can reach up to 2am
What is the aetiology of angina bullosa haemorrhagica
Relatively painless
No obvious trigger
Heal with no scarring within a few days
What must be ruled out before you can reassure a patient that the condition - angina bullosa haemorrhagica is harmless
Must rule out any autoimmune or bleeding Dorset’s
What risk factors for angina bullosa haemorrhagica would you report to a pt when giving advice surrounding the condition
Associations with the use of a steroid in her with a nebuliser
The eating of rough foodstuffs
Taking of very hot drinks
How can we manage angina bullosa haemorrhagica
There is no treatment available a present
Reassurance to the patient that it is begin
Explain known triggers and course of the disease
They can be annoying but do not progress systemically
If there is discomfort an analgesic mouthwash such as benzydamine hydrochloride may be effective
What kind of antibody attack happens in pempigoid?
A sub epithelial antibody attack
The antibodies cause separation from the basement membrane at the connective tissue and inflammatory exudate fills the space
What is the difference between mucous membrane pemphhigoid and cicatritial pemphigoid
In Cicatritial pemphiogid there is scarring
Why is there infection risk in pemphigoid
In areas of blister rupture there is exposed connective tissue and fluid from the area, this loss of epithelial barrier leads to infection risk
In pemphigoid, other than infection risk, what can leaking blisters lead to?
Dehydration
What is symblepharon
This happens in pemphigoid
It is when there is scarring in the eye, joining the conjunctiva too the eye surface \
Why when assessing pemphigoid or pemphigus must a perilesional biopsy be taken rather than the lister itself
This is because due to the damage to the epithelium in these conditions not enough epithelium will be present in the sample to make a diagnosis
When looking an immunofluorsence image, you see linear staining along the basement membrane what would this suggest?
Pemphigoid
What will be detected in immunofluoresnce along the basement membrane in standard pemphigoid
C3 and IgG
Why do we use immunosuppressant drugs such as azathioprine to manage pemphigoid and pemphigus
To try and prevent the antibody generation which is causing the disease
What is the commonest form of pemphigus
Pemphigus vulgaris
What happens in pemphigus
An intraepitheial bullae forms
The desmosomes are attacked by the antibodies causing loss of adhesion
As the fluid fills in adhesion is completely lost cashing thinning and eventual loss of the epithelium
Blisters- burst- spread
Are you more likely to see intact bullae in pemphigoid or pemphigus
Pemphigoid
What condition are Tzank cells characteristic of
Pemphigus
If looking at am immunofluoresnce image for pemphigus what would you expect to see?
Basket weave appearance
