Flashcards in Bullous disease Deck (22):
Infective causes of blistering (4)
S. aureus (staph scalded skin syndrome, impetigo)
Herpes virus (cold sores, eczema herpeticum)
Varicella virus (chicken pox, shingles)
Coxsackie virus (Hand, foot and mouth disease)
Neonate with fragile skin that blisters on contact
Commonest variant of pemphigus?
How does pemphigus vulgaris present? (2)
Flaccid blisters which rupture easily, and erosions; 50% patients have mouth involvement
What is the Nikolsky sign and what does it indicate? (2)
Top layers of skin slide away easily when rubbed; indicates either pemphigus or toxic epidermal necrosis
What are the cardinal pathological processes in pemphigus? (2)
Split within the epidermis; loss of adhesion epidermal keratinocytes (acantholysis)
What is the immunopathology of pemphigus? (2)
Bright staining on immunofluorescence against IgG and C3
Circulating antiepithelial antibody on indirect immunofluorescence (most patients)
Management of pemphigus (3)
High dose systemic steroids
Steroid-sparing agents such as AZT, cyclophosphamide, MTX are useful
Wound dressing/good oral care
Blistering skin disorder which usually affects the elderly; causes development of large tense blisters
Location of the split in bullous pemphigoid?
Deeper, at the DEJ
What symptom often precedes blister formation in pemphigoid?
Non-specific itchy rash
Management of pemphigoid (4)
General measures e.g. wound care
Topical/systemic steroids depending on disease extent
Tetracycline antibiotics e.g. doxycycline
Steroid sparing agents
Key differences between pemphigus and pempigoid?
Pemphigus is more superficial, blisters are flaccid and easily ruptured, occurs in younger people, involves the mouth
Pemphigoid is more common, deeper, blisters are large and tense, occurs in older people, doesn't involve the mouth
Key features of dermatitis herpetiformis (4)
intense pruritus (often prodromal)
clusters red papules and vesicles mainly on extensor surfaces
Association with gluten-sensitive enteropathy (i.e. villous atrophy on biopsy)
Where is the location of the "split" in dermatitis herpetiformis?
Metabolic cause of blistering (1)
Porphyria cutanea tarda
Which types of drug reaction can cause blistering? (4)
Erythema multiforme (more commonly target lesions)
Toxic epidermal necrolysis
Fixed drug eruptions
Target of the autoantibodies in a) pemphigoid b) pemphigus?
a) hemidesmosomes anchoring the basal cells to collagen fibres in the dermis; also BPAG1 and BPAG2 in the basement membrane
b) desmosomes connecting keratinocytes in the epidermis
Compare the immunofluorescence profiles of pemphigus, pemphigoid and dermatitis herpetiformis
a) IgG deposition in a "chicken-wire" pattern around cells within the epidermis
b) linear IgG deposition along the basement membrane
c) IgA deposition in clusters around the dermal papillae
What complications can pemphigus have?
Loss of thermoregulation leading to hypothermia
Loss of water and protein
Mucosal involvement leading to dysphagia, unable to replace losses
Portal for infection --> sepsis
What does coeliac serology look for?
IgA antibodies to tissue transglutaminase