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D20 Dermatology
Vesiculobullous Diseases Toronto Notes 2019 • immunofluorescenceshowslineardepositionofIgGandC3alongthebasementmembrane
• anti-basementmembraneantibody(IgG)(pemphigoidantibodydetectableinserum)
Prognosis
• healswithoutscarring,usuallychronic • rarelyfatal
Management
• prednisone0.5-1mg/kg/dayuntilclear,thentaper±steroid-sparingagents(e.g.azathioprine,cyclosporine, mycophenolate mofetil)
• topicalpotentsteroids(clobetasol)maybeaseffectiveassystemicsteroidsinlimiteddisease
• tetracycline±nicotinamideiseffectiveforsomecases
• immunosuppressantssuchasazathioprine,mycophenolatemofetil,cyclosporine
• IVIgandplasmapheresisforrefractorycases
Pemphigus Vulgaris
Clinical Presentation
• autoimmuneblisteringdiseasecharacterizedbyflaccid,non-pruriticintraepidermalbullae/vesicleson an erythematous or normal skin base
• maypresentwitherosionsandsecondarybacterialinfection
• sites:mouth(90%),scalp,face,chest,axillae,groin,umbilicus
• Nikolsky’ssign:epidermaldetachmentwithshearstress
• Asboe-Hansen sign: pressure applied to bulla causes it to extend laterally
Pathophysiology
• IgGagainstepidermaldesmoglein-1and-3leadtolossofintercellularadhesionintheepidermis
Epidemiology
• 40-60yrold,M=F,higherprevalenceinJewish,Mediterranean,Asianpopulations
• paraneoplasticpemphigusmaybeassociatedwiththymoma,myastheniagravis,malignancy,anduseof
D-penicillamine
Investigations
• immunofluorescence:showsIgGandC3depositionintraepidermally • circulatingserumanti-desmogleinIgGantibodies
Prognosis
• lesionshealwithhyperpigmentationbutdonotscar
• maybefatalunlesstreatedwithimmunosuppressiveagents
Management
• prednisone1-2mg/kguntilnonewblisters,then1-1.5mg/kguntilclear,thentaper±steroid-sparing agents (e.g. azathioprine, cyclophosphamide, cyclosporine, IVIg, mycophenolate mofetil, rituximab)
Dermatitis Herpetiformis
Clinical Presentation
• groupedpapules/vesicles/urticarialwhealsonanerythematousbase,associatedwithintensepruritus, burning, stinging, excoriations
• lesionsgrouped,bilaterallysymmetrical
• commonsites:extensorsurfacesofelbows/knees,sacrum,buttocks,scalp
Pathophysiology
• transglutaminaseIgAdepositsintheskinaloneorinimmunecomplexesleadingtoeosinophiland neutrophil infiltration
• 90%haveHLAB8,DR3,DQWZ
• 90-100%associatedwithanoftensubclinicalgluten-sensitiveenteropathy(i.e.celiacdisease)
• 30%havethyroiddisease;increasedriskofintestinallymphomainuntreatedcomorbidceliacdisease;
iron/folate deficiency is common
Epidemiology
• 20-60yrold,M:F=2:1
Investigations
• biopsy
• immunofluorescenceshowsIgAdepositsinperilesionalskin
Management
• dapsone(sulfapyridineifcontraindicatedorpoorlytolerated) • gluten-freedietforlife–thiscanreduceriskoflymphoma
Investigations
Pemphigus Vulgaris vs. Bullous Pemphigoid VulgariS = Superficial, intraepidermal, flaccid lesions
PemphigoiD = Deeper, tense lesions at the dermal-epidermal junction
Pemphigus Foliaceus
An autoimmune intraepidermal blistering disease that is more superficial than pemphigus vulgaris due to antibodies against desmoglein-1, a transmembrane adhesion molecule. Appears as crusted patches, erosions and/or flaccid bullae that usually start on the trunk. Localized disease can
be managed with topical steroids. Active widespread disease is treated like pemphigus vulgaris