Bullous disease

Question 1

Infective causes of blistering (4)

Answer 1

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)

Question 2

Neonate with fragile skin that blisters on contact

Answer 2

Epidermolysis bullosa

Question 3

Commonest variant of pemphigus?

Answer 3

Pemphigus vulgaris

Question 4

How does pemphigus vulgaris present? (2)

Answer 4

Flaccid blisters which rupture easily, and erosions; 50% patients have mouth involvement

Question 5

What is the Nikolsky sign and what does it indicate? (2)

Answer 5

Top layers of skin slide away easily when rubbed; indicates either pemphigus or toxic epidermal necrosis

Question 6

What are the cardinal pathological processes in pemphigus? (2)

Answer 6

Split within the epidermis; loss of adhesion epidermal keratinocytes (acantholysis)

Question 7

What is the immunopathology of pemphigus? (2)

Answer 7

Bright staining on immunofluorescence against IgG and C3

Circulating antiepithelial antibody on indirect immunofluorescence (most patients)

Question 8

Management of pemphigus (3)

Answer 8

High dose systemic steroids
Steroid-sparing agents such as AZT, cyclophosphamide, MTX are useful
Wound dressing/good oral care

Question 9

Blistering skin disorder which usually affects the elderly; causes development of large tense blisters

Answer 9

Bullous pemphigoid

Question 10

Location of the split in bullous pemphigoid?

Answer 10

Deeper, at the DEJ

Question 11

What symptom often precedes blister formation in pemphigoid?

Answer 11

Non-specific itchy rash

Question 12

Management of pemphigoid (4)

Answer 12

General measures e.g. wound care
Topical/systemic steroids depending on disease extent
Tetracycline antibiotics e.g. doxycycline
Steroid sparing agents

Question 13

Key differences between pemphigus and pempigoid?

Answer 13

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

Question 14

Key features of dermatitis herpetiformis (4)

Answer 14

intense pruritus (often prodromal)
clusters red papules and vesicles mainly on extensor surfaces
Subepidermal blistering
Association with gluten-sensitive enteropathy (i.e. villous atrophy on biopsy)

Question 15

Where is the location of the “split” in dermatitis herpetiformis?

Answer 15

Sub-epidermal

Question 16

Metabolic cause of blistering (1)

Answer 16

Porphyria cutanea tarda

Question 17

Which types of drug reaction can cause blistering? (4)

Answer 17

Erythema multiforme (more commonly target lesions)
Stevens-Johnson syndrome
Toxic epidermal necrolysis
Fixed drug eruptions

Question 18

Target of the autoantibodies in a) pemphigoid b) pemphigus?

Answer 18

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

Question 19

Compare the immunofluorescence profiles of pemphigus, pemphigoid and dermatitis herpetiformis

Answer 19

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

Question 20

What complications can pemphigus have?

Answer 20

Loss of thermoregulation leading to hypothermia
Loss of water and protein
Mucosal involvement leading to dysphagia, unable to replace losses
Portal for infection –> sepsis

Question 21

What does coeliac serology look for?

Answer 21

IgA antibodies to tissue transglutaminase

Question 22

Management of dermatitis herpetiformis

Answer 22

Gluten-free diet

Antibiotics e.g. tetracyclines, Dapsone