Clinical: Bullous Diseases

Question 1

What is the key investigation for immunobullous diseases?

Answer 1

-Eliptical incision taken from the edge of a recent blister

Question 2

What happens to the biopsy taken in immunobullous diseases?

Answer 2

Biopsy is halved:

• one half of sample is put in formalin for subsequent histology
• Other half is sent fresh for direct immunofluorescence

Question 3

What else should be sent for investigation in immunobullous diseases?

Answer 3

• Serum for indirect immunofluroscence

- Blister fluid should be sent for culture to exclude viral or bacterial infection

Question 4

What is the most common immunobullous disease?

Answer 4

Bullous Pemphigoid

Question 5

What is the average age of onset for Bullous Pemphigoid?

Answer 5

65

Question 6

Is there evidence of acantholysis in Bullous Pemphigoid?

Answer 6

No

Question 7

Explain the mechanism of Bullous Pemphigoid

Answer 7

• Circulating IgG antibodies react with a major/a minor antigen of the heme-desmosomes, anchoring basal cells to the basement membrane
• The result is local complement activation and tissue damage

Question 8

Name some of the pre-onset symptoms of Bullous Pemphigoid

Answer 8

Itch and an urticated erythematous rash

Question 9

Which has the tense and more fluid filled bullae, Bullous Pemphigoid or Pemphigus Vulgaris?

Answer 9

Bullous Pemphigoid

Question 10

Is mucosal involvement common in Bullous Pemphigoid, Pemphigus Vulgaris or both?

Answer 10

Pemphigus Vulgaris

Question 11

What is the histology of Bullous Pemphigoid?

Answer 11

Subepidermal blistering with an eosinophil rich inflammatory infiltrate

Question 12

What does the result of direct immunofluoresence in Bullous Pemphigoid show?

Answer 12

Presence of IgG and complement (C3) around basement membrane

Question 13

Why should a recent blister always be used?

Answer 13

In Bullous Pemphigoid older lesions may mini Pemphigus Vulgaris

Question 14

How is Bullous Pemphigoid managed?

Answer 14

• Most require systemic corticosteroids and aziothioprine

- Very potent topical steroids to all sites in the frail

Question 15

Explain how Pemphigus arises?

Answer 15

1) IgG autoantibodies made against desmoglein 3 (maintains desmosomal attachments)
2) Immune complexes form on cell surface
3) Complement activation and protease release
4) Disruption of desmosomes
5) Acanthyloysis (end result)

Question 16

What is Acanthylosis?

Answer 16

Lysis of intercellular adhesion sites

Question 17

What are the clinical features of Pemphigus?

Answer 17

• Skin AND mucus affected but sometimes just mucus
• Erosions common
• Trunk usually affected

Question 18

Why are blisters in Pemphigus easily ruptured?

Answer 18

due to high split in epidermis

Question 19

What is the histology of Pemphigus?

Answer 19

Intradermal blistering and acanthyolysis with positive immunofluorescence

Question 20

What can be a secondary cause of Pemphigus?

Answer 20

Drugs or underlying malignancy

Question 21

How many subtypes does Pemphigus have and which is the most common?

Answer 21

4, Pemphigus Vulgaris (80% of cases)

Question 22

How is Pemphigus managed?

Answer 22

High dose systemic corticosteriods

Question 23

Name an autoimmune blistering condition associated with coeliac disease

Answer 23

Dermatitis Herpetiformis

Question 24

What is the histology of Dermatitis Herpetiformis?

Answer 24

Subepidermal vesiculation in the dermal papillae and a neutrophil and eosinophil rich infiltrate

Question 25

Who does Linear IgA disease affect and what is the common cause?

Answer 25

Children, caused by drugs (particularly vancomycin)

Question 26

How do you differentiate between Bullous Pemphigoid and Pemphigus

Answer 26

Bullous PemphigoiD split is DEEPER, through DEJ

PemphiguS split is SUPERFICIAL, intra-dermal

Question 27

How can the Nikolsky sign distinguish between Bullous Pemphigoid and Pemphigus

Answer 27

Bullous Pemphigoid= negative

Pemphigus= postive