Pemphigus Flashcards
(41 cards)
Definition of pemphigus
- Group of auto-immune blistering diseases of the skin and mucous membranes that is characterized by
- Histologically intraepidermal blisters due to loss of cell-cell adhesion of keratinocytes
- Immunopathologically the finding of in vivo bound and circulating IgG autoantibodies directed against cell surface of keratinocytes
Classify pemphigus/divide
- pemphigus vulgaris
- pemphigus foliaceus
- paraneoplastic pemphigus
Describe the pathogenesis of pemphigus group shortly
- The function of desmoglein (which is NB in cell-cell adhesion) of keratinocytes is inhibited by IgG auto-antibodies -> blister formation
- Patients with pemphigus vulgaris and pemphigus foliaceous have IgG auto-antibodies against desmoglein 3 and desmoglein 1 respectively, while paraneoplastic pemphigus also have IgG auto-antibodies against plakin as well as T-cell mediated autoimmune reaction that leads to interface dermatitis
Define IgA pemphigus
- Characterised by IgA but not IgG auto-antibodies directed against keratinocyte cell surface and is divided into 2 major subtypes: intra-epidermal neutrophilic type and subcorneal pustular dermatosis type
Make key notes on fogo selvagem
Classification of pemphigus (bolognia)
Pathogenesis of pemphigus
target antigens in pemphigus
Molecular structure of pemphigus antigens
Localization of blisters - desmoglein compensation theory
Humoral and cellular aiuto-immunity in paraneoplastic pemphigus
Unusual clinical presentations of pemphigus vulgaris
Immunological mechenism of pathogenic auto-antibody production in pemphigus
Clinical features of pemphigus vulgaris
- Almost all patients painful erosions of oral mucosa
- More than half develop flaccid blisters/cutaneous erosions (skin)
2 subgroups
- mucosal dominant (mucosal erosions, minimal skin involvement)
-mucocutaneous (extensive skin blisters/erosions + mucosal involvement) - Mucosal lesions: painful erosions, intact blisters = rare, most common on buccal/palatine mucosa, may cause decrease food/liquid intake
- Dx may be delayed in patient with predominantly mucosal involvement
- Lesions can extend to vermillion lip: thick, haemorrhagic crust
- Can involve throat/oesophagus (hoarseness/difficulty swallowing)
- Can involve conjunctiva, nasal mucosa, vagina, labia, penis, anus
- Primary skin lesions: flaccid, thin-walled, easily ruptured blisters
-on normal skin/erythematous base
-fluid in bullae -> clear/haemorrhagic/turbid/seropurulent - Erosions large, covered with crust: little tendency to heal
- Lesions that heal -> hyperpigmentation with no scarring
- Pruritus = uncommon
- Positive nikolsky sign
- Bullae spread phenomenon: gentle pressure on intact bullae forces fluid to spread under skin away from pressure-> indirect nikolsky
- Pemphigus vulgaris may be fatal - loss of body fluid/infection
Make key notes on pemphigus vegetans
Make notes on pemphigus foliaceus
Make notes on pemphigus erythematosus (Senear Usher)
Make key notes on herpetiform pemphigus
Make notes on drug induced pemphigus
Make noted on paraneoplastic pemphigus
Make notes on IgA pemphigus
- Vesiculopustular eruption, neutrophilic infiltrate + circulating IgA auto-antibodies against cell surface of Keratinocytes (no IgG auto-antibodies)
- Middle-aged/elderly
- 2 types:
- subcorneal pustular dermatosis
-intra-epidermal neutrophilic type (IEN) - Flaccid vesicles/pustules on erythematous base/normal skin
- coalesce to form annular pattern with crust in center (sunflower like: IEN)
- Axilla and groin
- Mucosal involvement = rare
- Immune evaluation to differentiate from Sneddon wilkinson
-SPD type: IgA auto-antibodies upper epidermis
-IEN type: IgA auto-antibodies entire epidermis
- subclass: IgA1
Write broad notes on how to do a biopsy if pemphigus vulgaris is suspected
Draw a picture of preferred sites for obtaining biopsy specimens in auto-immune bullous diseasez
Make notes on the pathology of pemphigus vulgaris
