Disease Profiles: Blistering Skin Disorders Flashcards
Describe the clinical presentation of dermatitis herpetiformis
Intensely itchy symmetrical lesions on an erythematous and swollen base
Elbows, knees and buttocks often excoriated
How would you manage systemic bullous pemphigoid?
Oral steriods +/- tetracycline antibiotics +/- antihistamine
If no response - immunosuppression (azathioprine/methotrexate)
What would immunofluorescence of a sample from dermatitis herpetiformis show?
Granular deposits of IgA in dermal papillae
What would histology of a sample from bullous pemphigoid show?
Subepidermal blisters and inflammatory infiltrates (mainly eosinophils) within the blister
Describe the pathophysiology of bullous pemphigoid
Anti-hemidesmosome antibodies (IgG) react with a major and/or minor antigen of the hemidesmosomes anchoring basal cells to basement membrane
Complement is activated and causes tissue damage - derma-epidermal junction is interrupted and sub-epidermal blister forms
Describe the management of dermatitis herpetiformis
Gluten free diet +/- dapsone
What are tetracyclines used for in the management of bullous pemphigoid?
Steroid sparing agents
Describe the clinical presentation of pemphigus vulgaris
Fluid-filled, painful, fragile blisters which rupture to form shallow erosions
Involves skin esp. scalp, face, axillae, groin, trunk, may affect mucosa e.g. mouth, respiratory tract
How would you manage local bullous pemphigoid?
High potency topical steriods
What haplotype is dermatitis herpetiformis associated with?
HLA-DQ2 haplotype
What are antihistamines used for in the management of bullous pemphigoid?
Sedating and anti-puritic properties
What is pemphigus vulgaris?
Rare autoimmune bullous disease, most common (80%) subtype of the pemphigus group
How would you manage systemic pemphigus vulgaris?
High dose oral steriods + immunosuppression +/- rituximab
Describe the pathophysiology of dermatitis herpetiformis
IgA antibodies target gliadin component of gluten but cross react with connective tissue matrix proteins (TTG) - leads to immune complex formation, complement activation and inflammation
Tissue damage causes the formation of sub epidermal blisters
Which patient group is most likely to develop pemphigus vulgaris?
Usually presents in middle age (40-60)
Which autoimmune blistering disorder will be Nikolsky sign positive?
Pemphigus Vulgaris
What hypersensitivity reaction is responsible for the pathophysiology of bullous pemphigoid?
Type II
Which investigations would you perform in suspected dermatitis herpetiformis?
Bloods (anti-TTG), biopsy, immunoflorescence
What is the Nikolsky sign?
Blisters can be extended with gentle lateral pressure
Describe the pathophysiology of pemphigus vulgaris
IgG4 antibodies against desmosomal proteins lead to loss of keratinocyte adhesion in the skin and mucous membranes
What would a biopsy of a sample from pemphigus vulgaris show?
Sup-epidermal blisters with papillary micro-abscesses
What patient group is most likely to develop bullous pemphigoid?
Patient typically elderly (> 60 years)
How would you manage local pemphigus vulgaris?
Topical steriods + topical anaethetics
Patients with pemphigus vulgaris have an increased risk of which malignancy?
Small bowel lymphoma
What is bullous pemphigoid?
Subepidermal blister caused by an autoimmune reaction
What would a biopsy of a sample from pemphigus vulgaris show?
Intra-epidermal blister with accumulation of inflammatory cells within the dermis
Describe the clinical presentation of bullous pemphigoid
Large, tense, extremely itchy blisters on normal skin or erythematous base
Typically blisters will be distributed in flexural regions of trunk or proximal limbs
Well-demarcated erythematous plaques may occur weeks to months before the blisters
What would immunofluorescence of a sample from pemphigus vulgaris show?
Chicken wire deposition of IgG within the epidermis
What would immunofluorescence of a sample from bullous pemphigoid show?
Liner IgG and complement deposited around the basal membrane
Which patient group is most likely to develop dermatitis herpetiformis?
Peak incidence 15-40 years, strong association with coeliac disease
What is dermatitis herpetiformis?
Autoimmune bullous disorder associated with coeliac disease
