Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Dermatology PPT 12 Immunobullous Disorders Lecture Notes
AUTOIMMUNE
BULLOUS DISORDERS - II
BULLOUS PEMPHIGOID
vAcquired, non scarring, autoimmune, blistering disease
v Age ? elderly
vHistology ? subepidermal bullae
v Immunopathologically ? deposition of AutoAb and complement
along basement membrane zone (BMZ)
? ANTIGENS - BPAg1 (230kDa) or BP 230
BPAg 2 (180kDa) or BP 180
BP 230
vIntracellular protein synthesized by basal keratinocytes
vComponent of cytoplasmic plaque of hemi-desmosome
BP 180
vHemidesmosomal glycoprotein of basal keratinocytes
vSpans lamina lucida of dermoepidermal junction
vHas a short non collagenuous extracellular domain
and a long non collagenuous ectodomain that interacts
with anchoring filaments of the basement membrane
vAuto Ab directed against short NC 16A ectodomain
ANTIBODIES
? Anti BMZ antibodies in BP ? IgG 1 and IgG 4
Ig E (occasionally)
? IgG 4 and IgE target BP 180Ag in Bullous Pemphigoid
? Serum levels of IgG 4 and IgE reflect disease activity
CLINICAL FEATURES
? Age- elderly 60-75
? M>F
? Tense vesicles and bullae on urticated base/ normal skin
? Containing clear to turbid to haemorrhagic fliud
? Roof remain intact for several days as bullae is subepidermal.
? Sites ? lower abdomen, inner thighs, groin, flexural aspects of
limbs
? Palms and soles ? occasional
? Nikolsky's sign ?ve
? Asboe Hansen's sign ?ve
? Blister collapse and re-epithelialize
? For blisters that rupture, resulting erosions do not spread
? Erosions heal without scarring-post inflammatory pigmentary
changes, milia
? Musosa- 10-40%
? Pruritus common; may precede several years
CLINICAL VARIANTS
1. Localised
2. Childhood
3. Vesicular
4. Vegetating
5. Nodular
6. Drug induced
? Drug induced pemphigus
Oral drugs- penicillin, ampicillin, penicillamine,
frusemide,PUVA therapy, anti diabetics, sulfonamides,
clonidine, diclofenac, ibuprofen, practolol.
Topical ? anthralin, 5-FU, benzoyl benzoate
HISTOLOGY
? Subepidermal blister
? An intact epidermis as roof
of bulla
? Blister cavity ?
neutrophils, eosiniphils,
fibrin
Direct immunono flourescense(DIF)
? Linear pattern of IgG, mainly IgG4 (90%), along BMZ
? C3 deposition in 100% cases
IgG
C3
?Indirect immuno
flourescence (IIF)
?Circulating anti BMZ IgG Ab
(70%)
D/D
1. Pemphigus
2. Mucous membrane pemphigoid
3. Pemphigoid Gestationis
4. Linear IgA disease
5. Dermatitis herpetiformis
6. Bullous drug eruptions
Bul ous pemphigoid vs Pemphigus
BULLOUS PEMPHIGOID
PEMPHIGUS VULGARIS
Subepidermal blister, eosinophil redominant
Suprabasal blister with acantholysis;
inltrate, with neutrophils, lymphocytes, and
characteristic "row of tombstones"
monocytes and macrophages
Nikolsky sign (-)
Nikolsky sign (+)
Asboe-Hansen sign (-)
Asboe-Hansen sign (+)
Urticarial lesions precede tense
Flaccid blister on any skin surface;
bul ae
erosions most commonly observed
Mucous membrane lesions
Mucous membrane lesions presenting sign for
present in 10%
majority of patients
BPAg1 (230-kDa) or BPAg2
Desmoglein 3 (130 kDa);
(180-kDa) or type XVI collagen
desmoglein 1 (160 kDa)
DIF IgG in basement membrane
DIF IgG in intercel ular pattern
Waxing and waning course,
Fatal if untreated
occasional spontaneous
remission
TREATMENT
1. Suppression Of Inflammation
v Corticosteroids ?oral daily doses (0.5-0.75/ kg/day) ,
potent topical steroids
v tetracyclin, sulfones
2. Suppression Of Auto Ab Formation
vhigh dose corticosteroids ? DCP pulse,
vazathioprine, Mtx, cyclosporin,
v cyclophosphamide
3. Removal Of Antigens And Autoab-
v Plasmapheresis
4. Immuno- Modulation ? IV Ig
DERMATITIS HERPETIFORMIS
vRare chronic blistering disorder
vIntensely pruritic grouped vesicles on an
erythematous base
v DIF ? granular deposits of Ig A in dermal papillae
vAssociated with an gluten sensitive mostly
asymptomatic enteropathy
PATHOGENESIS
vPredominant autoantigen in DH ?epidermal
transglutaminase (TGe)
vPredominant antibody in DH ? IgA
vPathological processes in skin are initiated when
v TGe - IgA immune complexes are deposit in
papillary dermis and activate complement
CLINICAL FEATURES
vAge ?(2-3)rd decade
vClassical lesion start as a vesicles on an erythematous,
edematous base
v later new lesions arrange in groups
v intensely itchy
v most lesions excoriated; only crusts seen
vSite ? elbows, knees, buttocks, sacrum, shoulders, posterior
scalp,
vSymmetrical distribution
v Occasionally face
ASSOCIATIONS
Gluten Sensitive Enteropathy
vGluten protein present in grasses of species Triticeae, eg.
Wheat, rye, barley
vDue to non allergic sensitivity to gliadi fraction of gluten
vUsually asymptomatic
vDiarrhoea, steatorrhoea, abdominal distension, wt. loss
HISTOLOGY
vNeutrophillic microabscesses in tip of dermal papillae
vSlowly tips of dermal papillae separate from the epidermis
vSuch cleft coalesce to form a subepidermal bullae
DIF
vPerilesional non involved skin ? granular deposits of IgA in
picket shaped appearance
IIF-
v no circulating anti BMZ antibodies found
Immunoelectron Microscopy
vAmorphous grains of IgA deposits - DH bodies
D/D
vPapular urticaria
vScabies
v Neurotic excoriations
vErythema multiforme
TREATMENT
vGluten free diet life long
vDapsone 100-300mg daily
vSalfaslazine 0.5- 2g per day
vColchicine 0.6 mg tid
THANK YOU
This post was last modified on 07 April 2022