Vesiculobullous Disease Flashcards
List the 2 vesiculobullous diseases
- Bullous Pemphigoid
2. Pemphigus Vulgaris
Define vesiculobullous disease
- Uncommon chronic skin disorders caused by autoantibodies against various cutaneous proteins
- Significant quality of life issues
Epidemiology of bullous pemphigoid (BP)
- Bullous pemphigoid occurs equally in males and females.
- More prevalent in elderly patients.
- Usually in patients > 65 years of age with other comorbidities
- Median age of onset is 68-82
Causes of BP
- A drug, an injury, or skin infection can trigger the onset of disease
- There are HLA associations indicating genetic predisposition to the disease
Drug causes of BP
- furosemide
- captopril
- penicillamine
- antibiotics
Pathophysiology of BP
- Bullous pemphigoid is associated with the production of autoantibodies (IgG, +/- IgE immunoglobulins) targeting the basement membrane
- The binding of the autoantibodies to the proteins at the basement membrane stimulates destructive inflammatory cascade, predominantly mast cells and eosinophils
Name the 2 BP antigens that are autoantibody targets
Antibodies directed against 2 antigens: BP180 and BP230
Why is the basement membrane important in BP?
The basement membrane is important for the adhesion of the epidermis to the dermis, and so when targeted, leads to a separation (blister) in this space
What is the result of autoantibodies targeting the basement membrane in BP?
Results in the separation of the epidermis from the dermis forming a subepidermal blister
How does BP present on clinical exam?
- Prodromal erythematous, pruritic urticarial or papular eruption.
- Pruritus can be severe**
Where are the lesions with BP?
- Lesions usually bilateral and symmetric
- Predilection for groin, axillae, trunk, legs and flexural forearms.
What is the timeline for BP lesions?
-Evolves in weeks to months to bullae: small expanding to large, tense bullae, which rupture forming erosions.
Are the mucous membranes involved in BP?
- yes, but involvement rare - less than 10-20%
- if there is involvement, generally oral cavity.
Dx of BP
- Diagnosis is made based upon clinical, histologic, and IF features
- Most cases diagnosis confirmed by a skin biopsy (2 kinds: H&E + DIF)
Explain the H&E biopsy for BP
- biopsy of lesional skin (involved skin)
- report would reveal: “subepidermal blister with an inflammatory cell infiltrate containing eosinophils in the superficial dermis the presence of C3 deposition along the epidermal basement membrane zone”
- used for the confirmation of the diagnosis