Bullous Disorders Flashcards
Describe the blisters in bullous pemphigoid
Subepidermal
Describe the blisters in pemphigus vulgaris
Intra-epidermal
Which is more likely to present with erosions: pemphigoid or pemhigus
Pemphigus
Which is pemphigoid more likely to present with large tense bullae?
The blister is under the dermis so it lifts this entire layer to make a strong stable roof
How should you investigate bullous disorders?
Depends on what you suspect is the cause:
Infection - microscopy
Porphyria - porphyrin study
Contact dermatitis - patch testing
Autoimmune - biopsy with IF
What is the typical presentation of bullous pemphigoid?
>60yrs Large tense bullae Itchy erythematous plaques No scarring Mucosal lesions only in mouth
Outline the pathogenesis of pemphigoid
IgG autoantibodies attach BP180 and BP120 protein in hemidesmosomes
Can’t attach basal cells to the basement membrane
Lets fluid in
What does IF show in pemphigoid?
Linear IgG and complement around the basement membrane
basically a (green?) line surrounding by (amber) dots
How do you treat for generalised bullous pemphigoid?
Prednisolone 40-80mg daily for 2 weeks
Tetracyclines
Methotrexate
True or false:
Relapse is common with pemphigoid
False
How long does the average patient take to go into remission with pemphigoid?
3-6 months
How would you treat localised pemphigoid?
Highly potent topical steroids
Which is more common: pemphigoid or pemphigus?
Pemphigoid
Why are pemphigus blisters more likely to burst?
Intra-epidermal so they have a thinner roof
Where are skin lesions commonly found with pemphigus?
Scalp, face, axillae, groin
What is a positive Nikolsy sign?
When you can induce a blister in a patient but rubbing the skin
OR
you can shift a small blister sideways
What is the target of the autoantibodies in pemphigus?
Desmoglein proteins
Mostly type 3
What is desmolgein?
A membrane protein in the membrane of the cells in the spinous layer
What is the role of desmoglein?
Maintain integrity of the hemidesmosomes
What clinical sign may precede bullae in pemphigoid?
Itchy erythematous plauqes and papules for up to 1 year before
(these will not respond to low intensity steroids of fungal creams)
Which type of blistering occurs in dermatitis herpetiformis?
Subepidermal
Is Nikolsky’s sign positive in pemphigus, pemphigoid, DH or all?
Pemphigus
What does IF show in pemphigus?
IgG antibodies around the membrane in a “chicken wire pattern”
(the membrane (green?) looks like barbed wire and there are (amber?) dots in the gaps in the barbed wire)
Which is harder to treat: pemphigus or pemphigoid?
Pemphigus
