29- Pemphigus Flashcards
What are the three major forms of pemphigus?
- pemphigus foliaceus
- pemphigus vulgaris
- paraneoplastic pemphigus
What is the mean age of onset for pemphigus foliaceus and pemphigus vulgaris?
50 - 60 years old
What are the features of fogo selvagem?
- variant of pemphigus foliaceus.
- common in rural Brazil
- affects young adults and children in rural areas.
Which autoantibodies are found in pemphigus?
- IgG autoantibodies against cell surface of keratinocytes.
why do neonates with mothers who have pemphigus vulgaris get transient disease?
- Maternal IgG crosses the placenta.
What are the target antigens in pemphigus vulgaris?
Desmoglein 1 and 3 in the mucocutaneous type and
desmoglein 3 in the mucosal dominant type.
What are the target antigents in pemphigus foliaceus?
IgG autoantibodies to desmoglein 1
What are the target antigents in paraneoplastic pemphigus?
Desmoglein 1 , Desmoglein 3, Plectin, Epiplakin, Desmopakin I, Desmoplakin II, BPAG1, Envoplakin, Periplakin, A2ML1
Do neonates develop blisters in mothers who have pemphigus foliaceous?
Why or why not?
Neonates do not develop blisters in mothers with pemphigus foliaceus (As opposed to mothers with pemphigus vulgaris).
This is because the distribution
of Dsg 3 is found through out the epidermis Therefore the pemphigus
foliaceus sera containing only anti-Dsg1 IgG cannot induce blisters in neonatal skin.
Histologically, what other condition is indistinguisable from pemphigus foliaceus?
- staph scalded skin syndrome
- bullous impetigo
What are the clinical features of pemphigus vulgaris?
- painful erosions of the oral mucosa.
- haemorrhagic crusts.
- flaccid blisters and widespread cutaneous erosions.
- there are 2 subgroups: mucosal-dominant and mucocutaneoustype.
erosions in the mouth are of different sizes with an irregular and ill-defined border.
What are the clinical features of pemphigus vegetans?
- this is a variant of vegetative pemphigus vulgaris.
- flaccid blisters that becoming erosions and then form fungoid vegitations in intertrigoues areas and on the scalp and face.
- early lesions may present as pustules.
What are the 2 subtypes of pemphigus vegetans?
- Neumann type
- mild Hallopeau type
What are the clinical features of pemhpigus foliaceus?
- scaly crusted cutensoud erosions on an erythematous base.
- no clinically apparent mucosal involvement
- seborrheic in distrubution
- oral manifestations are rare.
What are the clinical features of Senear-Usher syndrome?
- localized variant of pemehigus foliaceus.
- plaques in the malar region of the face and other seborrheic areas.
What are the clinical features of herpetiform pemphigus?
- erythematous urticarial plaques
- tense vesicles presenting in a herpetiform arrangement.
What drugs induce pemphigus
- penacillamine
- captopril
*in patients recieving penicillamine pemphigus foliaceus is seen more commonly than pemphigus vulgaris.
what is the proposed mehanism behind why penacillamine and captopril cause pemphigus?
The sulfhydryl groups in penacillamine interact with Dsg1 and Dsg3.
What are the most commonly associated neoplastsm for paraneoplastic pemphigus?
- non-Hodgkin lymphoma
- chronic lymphocytic leukemia
- Csaatleman disease
What is the clinical presentation of paraneoplastic pemphigus?
- intractable stomatitis
- most patients have a severe pseudomembranous conjunctivitis.
- polymorphic cutaneous findings including blisters, EMlike lesions and liechnoid eruptions.
- occurence of blisters and erythema multiforme-like lesions on the pams and soles differentiates paraneoplastic pempigus from pempigus vulgaris.
What respiratory features do patients with paraneoplastic pemphigus get>
bronchiolitis obilterans.
What are the 2 distinct types of IgA pemphigus?
- subcorneal pustular dermatosis type
- intraepidermal neutrophilic type
What is the clinical presentation of IgA pemphigus?
- flaccid vesicles or pusutls
- pusutls form annular or circinate pattern with crusts in the centre of the lesion.
What condition is subcorneal pustular dermatosis type of IgA pemphigus clinically and histologically indistinguishable from?
Classic subcornal pustular dermatosis.
What is seen on DIF in IgA pemphigus?
IgA deposition on the cell surfaces of epidermal keratinocytes
IgA autoantibodies react with upper epidermal surfaces in subcorneal psutlar dermatosis type .
in the intraepiermal enturophillic type - IA autoantibodies foudn in the entire epidermis.
What subclass of IgA autoantibodies if found in IgA pemphigus?
- IgA1.
What are the characteristic histologic findings of pemphigus?
- acantholysis
-intraepidrmal blistr formation
acantholysis above the basal layer
-“rounded keratinocytes’
What are the causes of an eosinophillic spongiosis?
- pemphigus vulgaris
- pemphigus foliaceous
-BP - pemphigoid gestationis
- mumcous membrane pemphigoid
- Linear IgA bullous dermatoses
Inset-bite reaction
-drug eruptin
-Id reaction
-Wells sh dro e
-PUPP - first stage of incontentia pigmenti
- atopic dermatitis
- contact dermatitis
-MF - prurigo pigmentosa
-Still disease
What are the histological findings of paraneoplastic pemphigus?
- variability in pemphigus vulgaris-like, EM-like, LP like histology.
what does indirect immunoflurescence examine?
patient’s sera is examined inorder to demonstrate circulating IgG autoantibodies against epithelial cell surfaces.
What is the recommended indirect immunoflurescence substrate for pemphigus vulgaris and pemphigus foliaceous?
Pemphigus vulgaris - monkey esophagus.
pemphigus foliaceous - human skin/ ginea pig esophagus (anti Dsg1)
What is the recommended indirect immunoflurescence substrate for paraneaoplastic pemphigus?
monkey esophagus.
guinea pig esophagus (anti Dsg1)
and rat bladder
What is the recommended indirect immunoflurescence substrate for bullous pemphigoid, Linear IgA bullous dermatoses
Human skin - salt split
What is the recommended indirect immunoflurescence substrate for mucous membrane pemphigoid?
human skin - salt-split, normal oral or genital mucosa.
What are the differential diagnosis for mouth ulcerations?
- acute herpetic stomatitis
-aphthous stomatitis
-EM/SJS,
lichen planus,
systemic lupus
mucous membrane pemphigoid. - Hailey-Hailey disease
What are the differential diagnosis of pemphigus foliaceus?
- subcorneal pustular dermatosis, subacute cutaneous LE and seborrhic dermtatitis, bu,llous impetigo.
What is the treatment ladder for pemphigus vulgaris?
- oral prednisone 1mg/kg/day
- Azathioprine
- MMF
- CsA
- pulsed methyl pred
- cyclosporine
- MTX
- plasmapheresis
high dose IVIg - Rituximab
- Extracoporeal photopheresis.
how does rituximab work in pemphigus?
- induces a depletion of CD20+ B cells and a decline in IgG.
- also decreases desmoglein-specific T cells.
What is the treatment for paraneoplastic pemphigus?
- removal of tumours like thymomas or Castelman diseases. It may take 6-18 months to see complete resolution of lesions.
What is the treatment for IgA pemphigus?
Dapsone is the drug of choice.
Clinical response seen within 24-48 hours.
Sufapyridine and acitretin are useful alternatives.
