Bullous disease Flashcards
What is pephigus vulgaris?
A potentially fatal blistering disease occurring in all races but commoner in Ashkenazi Jews and possibly in people from the Indian subcontinent
What age does pemphigus normally affect?
<40 years
What is thought to be the cause of pemphigus vulgaris?
IgG4 against the desmosomal protein desmoglein 1 and 3 is pathogenic in this disease and the autoantibodies can be measured as markers of disease activity. Desmoglein 1 and 3, an adhesion molecule, is expressed in skin and mucosal surfaces, so both will blister
What layer does pemphigus vulgaris affect?
Suprabasal layer - Skin biopsy shows a superficial intraepidermal split just above the basal layer with acantholysis (separation of individual cells).
What are features of pemphigus vulgaris?
- Thin roofed & flaccid blisters - easily ruptured
- Uusally No Prodromal Symptoms
- Affected skin painful put not pruritic
- Nikolsky Sign – slight rubbing exfoliates the outermost layer of skin (not present in pemphigoid)
What are characteristic of blisters seen in pemphigus vulgaris?
Fragile - rupture easily
What is Nikolsky’s sign?
Blisters can be extended with gentle sliding pressure
How would you manage pemphigus vulgaris?
- Oral steroids
- IVIG
- Plasmapharesis - severe cases
What might you see on skin biopsy in someone with pemphigus vulgaris?
Loss of cohesion between keratinocytes (acantholysis)
What layer does pemphigus foliaceus affect?
Subcornial
What are features of pemphigus foliceus?
Blisters and erosions often start in a seborrhoeic distribution (scalp, face, upper chest) before becoming more widespread
What is bullous pemphigoid?
The primary autoimmune blistering disorder due to IgG autoantibodies to basement membrane. Autoantibodies against a 230 kDa or 180 kDa hemidesmosomal protein (‘bullous pemphigoid antigen 1’ and ‘type XVII collagen’) play an aetiological role.
Which blisters are deeper; those in pemphigus or bullous pemphigoid?
Bullous pemphigoid
What layer is most affected in bullous pemphigoid?
Subepidermal
What are features of bullous pemphigoid?
- Often a pruritic prodromal rash & region
- Thick, tense blisters & erosions - flexurral regions of limbs
- Usually heal without scarring
What might you see on skin biopsy in someone with bullous pemphigoid?
Separation of subepidermal layer
How would you manage someone with bullous pemphigoid?
- Potent topical steroids - Clobetasol
- Oral Prednisolone - with GI protection/bone protection
- Immunosuppressants
What is the pathophysiology of bullous pemphigoid?
Autoimmune, subepidermal blistering due to IgG autoantibodies for the basement membrane proteins BP1 and BP2. IgG bind to basement membrane and activate inflammatory cascade.
What are causes of blistering disorders?
- Infection - e.g. herpes
- Insect bites
- Friction/trauma
- Eczema
- Drugs - ACEi, furosemide
- Immunobullous disorders - pemphigoid, pemphigus, dermatitis herpatiformis
What is dermatitis herpatiformis?
A rare blistering disorder associated with gluten-sensitive enteropathy (coeliac disease)
What does skin biopsy of dermatitis herpatiformis show?
Subepidermal blister with neutrophil microabscesses in the dermal papillae
What are features of dermatitis herpatiformis?
- Small, intensely itchy blisters of the skin - predilection for the elbows, extensor forearms, scalp and buttocks
- Tops of the blisters usually scratched off - crusted erosions are often seen at presentation
How would you treat dermatitis herpatiformis?
Gluten free diet
What age group does pemphigoid normally occur in?
Elderly
