Vesiculobullous Lesions 2

Question 1

What is bullous lichen planus?

Answer 1

Condition with many of the features of pemphigoid superimposed on lichenoid histological pattern

Question 2

What is pemphigoid?

Answer 2

Sub epithelial antibody attack resulting in persistent thick walled blisters (can be clear or blood filled)

Question 3

How does damage to epithelium occur in pemphigoid?

Answer 3

Antibodies cause separation of epithelium from connective tissue at basement membrane by targeting hemi-desmosomes
-> full thickness of epithelium is released with fluid and inflammatory exudate filling space

Question 4

Where does the fluid in pemphigoid blisters come from?

Answer 4

Fluid comes from connective tissue

As a result of immunological damage- RBCs may go into fluid giving it blood filled appearance

Question 5

What are the types of pemphigoid?

Answer 5

Bullous Pemphigoid - skin

Mucous Membrane Pemphigoid – all mucous membranes affected (eye, genital, oral)

Cicatritial Pemphigoid – subset of mucous membrane- presence of scarring (different epitopes on same antigen involved in generation of lesion)

Question 6

How should a biopsy of pemphigoid be carried out?

Answer 6

Take from peri-lesional tissue to aid diagnosis
-> as it is impossible to guarantee that epithelium will remain attached to underlying mucosa (characteristic features should still be seen)

Question 7

How does pemphigoid appear histologically?

Answer 7

Split at junction of epithelial and connective tissue due to damage of heme-desmosomes at BM

Question 8

How is pemphigoid tested for?

Answer 8

 DIF is best- immunofluorescent staining can be seen along BM (Linear basement membrane staining)
-> fluorescein tag is attached to antibody which binds to circulating pemphigoid antibody which binds to antigen in BM

 Antibody to which stain is bound can be c3 (usually always involved), IgG, IgM and IgA
-> Disease may behave differently depending on antibody triggering issue

Question 9

How does staining appear in dermatitis herpetiformis appear?

Answer 9

Granular deposits of C3 and IgA seen
-> non linear like pemphigoid

Question 10

What condition is DH associated with?

Answer 10

Coeliac

Question 11

What can scarring of mucosa due to pemphigoid result in?

Answer 11

Narrowing of oro-pharynx (can be invisible)

Symblepharon- scarring of conjunctiva can bind eye surface to eyelid (restricts eye movement- dipoplia)
-> checked regularly by optician/ophthalmologist to see if this is developing

Question 12

Which other healthcare professionals are involved in managing pemphigoid (esp circatritial)

Answer 12

 Ophthalmologist
 Dermatologist
 Oral physician

Question 13

How is pemphigoid managed?

Answer 13

Immune suppressants to prevent antibody generation causing disease:

Steroids

IMD- azathioprine, mycophenolate, dapsone and biologics

Question 14

How does damage in pemphigus occur?

Answer 14

Circulating antibody is formed against desmosome tissue which holds cells together (not hemidesmosomes)
-> these cells lose adhesion to each other as a result

Intraepithelial bullae form- there may only be a few layers of cells above or around lesion but fluid fills spaces causing drift (epithelium is initially thinned but is then completely lost)

Question 15

What is the main difference between pemphigus and pemphigoid?

Answer 15

In pemphigus- intact bulla are rarely seen
-> presents as areas of surface loss and mucosal erosion

Question 16

What areas are affected by pemphigus, what is the usual sequence?

Answer 16

Often presents orally first, can take up to 3 years for skin lesions to present
-> Skin also suffers from erosive loss of cell structure and widespread loss of epithelial covering (fluid loss and infection risk)

Question 17

Which groups are more likely to suffer from pemphigus?

Answer 17

Over 50s

Females

Ashkenazi jew population

Question 18

What are the histological features of pemphigus?

Answer 18

 Loss of epithelium and shedding of epithelial layer

 Supra-basal (split occurs above basement membrane)

 Tzank cells are characteristic

Question 19

What gives the basket weave appearance when immunofluorescence of pemphigoid is carried out?

Answer 19

Antibody attacks desmosomes which are present on many surfaces of epithelial cells giving immunofluorescent surrounding
-> different from linear BM staining in pemphigoid

Question 20

What is the commonest form of pemphigus?

Answer 20

Vulgaris

Question 21

Which antibodies are commonly identified in pemphigus vulgaris?

Answer 21

C3 and IgG

Question 22

How does pemphigus present clinically?

Answer 22

 Erosions rather than blisters (same in skin and mouth)
-> Intact bullae are rare- thin walled intra-epithelial blisters

 Can affect any part of oral mucosa

 Appears like desquamative gingivitis in mouth- loss of epithelial covering OR as area covered with fibrinous exudate

Question 23

How is pemphigus managed?

Answer 23

High dose of steroids, biologics and immunosuppressants are required to stop erosions and loss of epithelial coverage

-> Biologics are preferred as other medicines put patient at risk of other diseases

Question 24

Why must pemphigoid and pemphigus be managed by specialists?

Answer 24

They can be fatal