-
V-B lesions can be classified as:
- Primary e.g. Pemphigus
- Secondary e.g. physical, chemical burn
- Congenital
-
Most primary causes of V-B lesions are?
Immunobullous disorders
-
Give examples immunobullous disorders PPLED?
- Pemphigus
- Pemphigoid
- Linear IgA
- Epidermolysis Bullosa
- Dermatitis Herpetiformis
-
Give eg.s of congenital causes:
Epidermolysis bullosa
-
They result from?
Loss of attachment between cells (intraepi) or between cells and CT (sub-epi)
-
What are most V-B disorders?
- All sub-epi
- EXCEPT pemphiGUS Vulgaris and viral infections
- EM can have both
-
Of the intra-epi lesions, name the two mechanisms?
- Pemphigus - acantholytic (breaks down the attachment apparatus desmosomes)
- Viral - non acantholytic (cell death)
-
Pemphigus types:
- Most common Vulgaris (70%)
- Vegetans
- Paraneoplastic
-
Who gets Pemphigus?
- Middle age
- Jewish/Italian/Mediterranean
- Female>male
-
Clinical fts Pemphigus:
- SKIN - limbs, trunk, genitalia, lip and nose crusting
- MUCOSA - Blisters, become erosions, desquamative gingivitis, +Nikolsky�s sign
- Other mucosa, e.g. conjunctiva
-
Histopath of Pemphigus:
- Inta-epi bulla produced by acantholysis
- Tzank cells in vesicle fluid
- Rupture of vesicle - ulcer with inflamm infiltrate in floor
-
Investigations
- DIF - IgG to intra-cellular epi
- IIF - (serum)- increase titre of circulating antibodies Desmoglein 3 (and some pts Desmoglein 1)
-
How can you monitor the condit?
Increase titre indicates increased severity
-
Treatment of pemphigus?
- Steroids eg. 80-100g/day
- and Azathioprine - allow steroid dose to be lower
- Screen pts before giving Aza, they might have an enzyme breaking it down
- Consult dermatologist, opthamologist
-
Paraneoplastic pemphigus is assoc with?
- partic lymphomas and leukaemia
- Usually resolves if cancer resolves
-
Pemphigoid, 2 major clinical types?
- Bullous Pemphigoid - SKIN
- MMP - Mucosal (skin rare)
-
Who gets MMP?
Similar to Pemphigus, Middle aged, female
-
Name some of the mucosal surfaces affected:
- OM (>90%)
- Conjunctiva (>90%)
- Nasopharynx 35%
- Larynx, oesophagus
-
What do they get with MMP?
- Bullae/erosions (if ruptured)
- Can be blood filled
- Erosions are longer lasting, persistent, slow to heal, fibrinous base
- Dequamative ging common
- May have +Nikolsky
-
Histo of MMP?
- Sub epi bullae
- The epi forms roof of bullae
- CT is floor
- CT infiltrated with inflamm
-
Investigations for MMP
- DIF - binding of anti C3/ IgG/M to BM
- IIF - generally low levels of Autoantibodies, can be -ve even!
-
Treatment of MMP?
- Mild - topical steroids
- Mod-severe - dapsone, prednis + azathioprine
-
Is MMP fatal?
- No, but has a chronic course, can lead to blindness, therefore Tx as early as poss.
- Opthalmic assess
-
Complications of MMP:
- Blindness from conjuntival scarring
- Laryngeal scarring - stenosis
- Oesophageal scarring - stricture
-
MMP diff dx?
- Pemphigus
- Linear IgA
- Angina bullosa haemorragica
- Erosive LP
-
Linear IgA name 4 fts?
- Sub epi
- Very similar to MMP
- Oral and occ
- DIF linear deposition of IgA at BMZ
-
Dermatitis Herpetiformis 4 fts?
- Rare, usually assoc with Coeliac
- Skin - pruritic rashes at elbow, knees
- OM in only 10% pts (bullae, desquamitive ging�)
-
What is Erythema multiforme?
Acute, often recurrent, HYPERSENSITIVITY REACTION.
-
Possible causes of EM?
- Idiopathic
- Drug reaction eg. Anticonvulsants, barbituates, sulphonamides, antibiotics
- Infection eg. H. simplex
- Other eg. Preg, malig
-
Who gets it?
- Younger people 20-40yo
- 20% in children
-
Describe the spectrum of clinical fts of EM:
- Minor - affects only 1 site, not debilitating
- Major - widespread, life threatening, Steven-Johnson syndrome
-
What is EM often characterised by?
- RAPID ONSET
- Serosanguinous exudates of the lips
- Oral ulceration
- Other mucosa
- Target lesions on skin
-
Rashes in EM can vary, describe:
Patchy erythema to target lesions and bullae
-
What makes you think viral infection as a differential?
Prodromal symps may be experienced
-
Steven-Johnson syndrome involves which sites?
Skin + 2 or more mucosal lesions
-
Oral lesions of SJS?
- Widespread irreg fibrin covered erosions
- Diffuse and widespread macules that progress to blisters and ulceration
- Lips - swollen, cracked, bleeding, crusting, drooling
- Recurrence. Lasts 10-20days
-
Skin lesions of SJS?
- Macules/Papules - pruritic or erythematous
- Large target lesions - centre is a necrotic ulcer
- If very severe, large skin bullae - Toxic Epidermal necrolysis
-
Other mucosa in SJS?
- Eyes - lacrimation, redness, bloodshot, conjunctivitis, adhesion of eyelid to eyeball
- Genital lesions
-
Dx of EM?
- Clinical
- Serology (cause?)
- Biopsy - Variable histopatho - sub and intra epi
-
EM Tx?
- Admit
- Fluids, Nutrients if anorexia
- PEG, nasogastric
- Tx cause
- Corticosteroids
|
|
