Bullous Pemphigoid

Question 1

What is the most common autoimmune blistering disorder?

Answer 1

Bullous pemphigoid

Question 2

Bullous Pemphigoid is usually acute or chronic? And mortality is low or high

Answer 2

• chronic, low mortality

Question 3

Age group most affected by Bullous Pemphigoid?

Answer 3

• Elderly >60 y/o

Question 4

Genetic predisposition of Bullous Pemphigoid?

Answer 4

• a/w HLA- DQB*0301

Question 5

Describe pathogenesis of Bullous Pemphigoid:

Answer 5

• IgG (IgG 1 +4) autoantibodies bind hemidesmosomal proteins—> complement activation—> eosinophil and neutrophil recruitment–> release of MMP, proteases and neutrophil elastase–> degradation of ECM proteins—> subepidermal blister

Question 6

Most important target antigen in Bullous Pemphigoid:

Answer 6

BP 180 (BPAG2)

• BP 230 (BPAG1) is not the primary mediator, but plays a role

Question 7

Main pathogenic target of BP180 in Bullous Pemphigoid is:

Answer 7

NC16A

Question 8

Early clinical features of Bullous Pemphigoid

Answer 8

• typically non-bullous phase (early)
• may have isolated intense pruritis
• fixed uriticarial papules/plaques
• persistent polymorphous eruption

Question 9

Parts of body Bullous Pemphigoid affects most commonly:

Answer 9

• trunk, abdomen, flexural extremities

Question 10

Bullous phase of Bullous Pemphigoid presents as:

Answer 10

• tense- fluid filled vesicles/bullae arrising on urticarial background with intense pruritis

- bullae rupture to leave erosions and crusted areas

Question 11

How often do you see peripheral eosinophilia in Bullous Pemphigoid?

Answer 11

• 50%

Question 12

Histopath of Bullous Pemphigoid urticarial early phase:

Answer 12

• eosinophilic spongiosis w/ eos lining up at DEJ and vacuoles at DEJ (represent early blisters)

Question 13

Histopath of Bullous phase of Bullous Pemphigoid:

Answer 13

• subepidermal split w/ numerous eos in blister cavity
• may see flame figures at any phase

Question 14

DIF of Bullous Pemphigoid will show:

Answer 14

• Linear C3 (n-serrated pattern) and IgG located along DEJ

Question 15

How can you differentiate between Bullous Pemphigoid and Epidermolysis bullosa acquisita, what will it reveal?

Answer 15

1. • with salt-split skin DIF

- will show “roof staining” for BP and “floor staining” for EBA

2. Can also examin serration pattern (n-serrated vs u-serrated

Question 16

Do IIF levels in Bullous Pemphigoid patient correlate with disease activity?

Answer 16

• NO! (unlike PV/PF)

Question 17

How can you monitor treatment response/disease activity in Bullous Pemphigoid patient?

Answer 17

• ELISA serum test for detecting circulating antibodies to BP180 and BP230

Question 18

First line tx for Bullous Pemphigoid:

Answer 18

• systemic steroids + steroid-sparing immunosuppresives (MMF, MTX, azathioprine, cyclophosphamide)
• can also use high potency topical steroids (high risk of atrophy)

Question 19

Other treatment options for Bullous Pemphigoid (not first line)

Answer 19

• Tetracycline + nicotinamide
• Dapsone
• Rituximab (recalcitrant cases)
• IVIG, plasma exchange

Question 20

There is a high chance of relapse of Bullous Pemphigoid if ______

Answer 20

• increased ELISA levels and/or positive DIF at time of therapy cessation
• remember that these correlate with disease activity