Download MBBS Dermatology PPT 12 Immunobullous Disorders Lecture Notes

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BULLOUS PEMPHIGOID


vAcquired, non scarring, autoimmune, blistering disease
v Age ? elderly

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vHistology ? subepidermal bullae

v Immunopathologically ? deposition of AutoAb and complement

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along basement membrane zone (BMZ)

? ANTIGENS - BPAg1 (230kDa) or BP 230
BPAg 2 (180kDa) or BP 180
BP 230

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vIntracellular protein synthesized by basal keratinocytes
vComponent of cytoplasmic plaque of hemi-desmosome

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BP 180
vHemidesmosomal glycoprotein of basal keratinocytes
vSpans lamina lucida of dermoepidermal junction
vHas a short non collagenuous extracellular domain

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and a long non collagenuous ectodomain that interacts

with anchoring filaments of the basement membrane

vAuto Ab directed against short NC 16A ectodomain

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ANTIBODIES

? Anti BMZ antibodies in BP ? IgG 1 and IgG 4

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Ig E (occasionally)

? IgG 4 and IgE target BP 180Ag in Bullous Pemphigoid

? Serum levels of IgG 4 and IgE reflect disease activity

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CLINICAL FEATURES
? Age- elderly 60-75
? M>F

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? 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

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limbs

? Palms and soles ? occasional
? Nikolsky's sign ?ve

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? Asboe Hansen's sign ?ve


? Blister collapse and re-epithelialize
? For blisters that rupture, resulting erosions do not spread

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? Erosions heal without scarring-post inflammatory pigmentary

changes, milia

? Musosa- 10-40%

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? Pruritus common; may precede several years
CLINICAL VARIANTS

1. Localised

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2. Childhood
3. Vesicular
4. Vegetating
5. Nodular
6. Drug induced

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? Drug induced pemphigus

Oral drugs- penicillin, ampicillin, penicillamine,

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frusemide,PUVA therapy, anti diabetics, sulfonamides,

clonidine, diclofenac, ibuprofen, practolol.

Topical ? anthralin, 5-FU, benzoyl benzoate

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HISTOLOGY

? Subepidermal blister

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? An intact epidermis as roof

of bulla

? Blister cavity ?

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neutrophils, eosiniphils,

fibrin

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Direct immunono flourescense(DIF)

? Linear pattern of IgG, mainly IgG4 (90%), along BMZ
? C3 deposition in 100% cases

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IgG

C3

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?Indirect immuno

flourescence (IIF)

?Circulating anti BMZ IgG Ab

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(70%)

D/D

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1. Pemphigus

2. Mucous membrane pemphigoid

3. Pemphigoid Gestationis

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4. Linear IgA disease

5. Dermatitis herpetiformis

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6. Bullous drug eruptions


Bul ous pemphigoid vs Pemphigus

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BULLOUS PEMPHIGOID

PEMPHIGUS VULGARIS

Subepidermal blister, eosinophil redominant

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Suprabasal blister with acantholysis;

inltrate, with neutrophils, lymphocytes, and

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characteristic "row of tombstones"

monocytes and macrophages
Nikolsky sign (-)

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Nikolsky sign (+)

Asboe-Hansen sign (-)

Asboe-Hansen sign (+)

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Urticarial lesions precede tense

Flaccid blister on any skin surface;

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bul ae

erosions most commonly observed

Mucous membrane lesions

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Mucous membrane lesions presenting sign for

present in 10%

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majority of patients

BPAg1 (230-kDa) or BPAg2

Desmoglein 3 (130 kDa);

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(180-kDa) or type XVI collagen

desmoglein 1 (160 kDa)

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DIF IgG in basement membrane

DIF IgG in intercel ular pattern

Waxing and waning course,

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Fatal if untreated

occasional spontaneous

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remission
TREATMENT

1. Suppression Of Inflammation

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v Corticosteroids ?oral daily doses (0.5-0.75/ kg/day) ,

potent topical steroids

v tetracyclin, sulfones

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2. Suppression Of Auto Ab Formation

vhigh dose corticosteroids ? DCP pulse,

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vazathioprine, Mtx, cyclosporin,

v cyclophosphamide

3. Removal Of Antigens And Autoab-

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v Plasmapheresis

4. Immuno- Modulation ? IV Ig

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DERMATITIS HERPETIFORMIS
vRare chronic blistering disorder

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vIntensely pruritic grouped vesicles on an

erythematous base

v DIF ? granular deposits of Ig A in dermal papillae

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vAssociated with an gluten sensitive mostly

asymptomatic enteropathy

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PATHOGENESIS
vPredominant autoantigen in DH ?epidermal

transglutaminase (TGe)

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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

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CLINICAL FEATURES
vAge ?(2-3)rd decade
vClassical lesion start as a vesicles on an erythematous,

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edematous base

v later new lesions arrange in groups
v intensely itchy

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v most lesions excoriated; only crusts seen
vSite ? elbows, knees, buttocks, sacrum, shoulders, posterior

scalp,

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vSymmetrical distribution
v Occasionally face


ASSOCIATIONS

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Gluten Sensitive Enteropathy
vGluten protein present in grasses of species Triticeae, eg.

Wheat, rye, barley

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vDue to non allergic sensitivity to gliadi fraction of gluten
vUsually asymptomatic
vDiarrhoea, steatorrhoea, abdominal distension, wt. loss

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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

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DIF
vPerilesional non involved skin ? granular deposits of IgA in

picket shaped appearance

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IIF-
v no circulating anti BMZ antibodies found

Immunoelectron Microscopy
vAmorphous grains of IgA deposits - DH bodies

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D/D

vPapular urticaria

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vScabies
v Neurotic excoriations
vErythema multiforme
TREATMENT

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vGluten free diet life long

vDapsone 100-300mg daily
vSalfaslazine 0.5- 2g per day
vColchicine 0.6 mg tid

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