ABD Reading 3 — Questions and Answers
Question 1: A patient presents with a tense subepidermal blister and linear IgG along the basement membrane on direct immunofluorescence. What is the diagnosis?
- Bullous pemphigoid (Correct answer)
- Pemphigus vulgaris
- Dermatitis herpetiformis
- Linear IgA disease
Correct answer: Bullous pemphigoid
Bullous pemphigoid shows tense subepidermal bullae with linear IgG and C3 at the dermoepidermal junction.
Question 2: Which antigens are targeted in bullous pemphigoid?
- BP180 and BP230 (Correct answer)
- Desmoglein 1 and 3
- Type VII collagen
- Transglutaminase
Correct answer: BP180 and BP230
Autoantibodies in bullous pemphigoid target hemidesmosomal proteins BP180 and BP230.
Question 3: Pemphigus vulgaris demonstrates which immunofluorescence pattern?
- Intercellular 'fishnet' IgG (Correct answer)
- Linear basement membrane IgG
- Granular IgA in dermal papillae
- Negative immunofluorescence
Correct answer: Intercellular 'fishnet' IgG
Pemphigus vulgaris shows intercellular 'chicken wire' or fishnet IgG deposition between keratinocytes.
Question 4: Dermatitis herpetiformis is associated with which systemic condition?
- Celiac disease (Correct answer)
- Diabetes mellitus
- Hyperthyroidism
- Crohn disease
Correct answer: Celiac disease
Dermatitis herpetiformis is strongly linked to gluten-sensitive enteropathy (celiac disease).
Question 5: Which drug is first-line for dermatitis herpetiformis symptom control?
- Dapsone (Correct answer)
- Prednisone
- Azathioprine
- Rituximab
Correct answer: Dapsone
Dapsone rapidly relieves the intense pruritus of dermatitis herpetiformis.
Question 6: A positive Nikolsky sign indicates:
- Epidermal detachment with lateral pressure (Correct answer)
- Pinpoint bleeding after scale removal
- Wheal after stroking a lesion
- Vesicles after minor trauma
Correct answer: Epidermal detachment with lateral pressure
The Nikolsky sign is separation of the epidermis with tangential pressure, seen in pemphigus and TEN.
Question 7: Before starting dapsone, which laboratory test is essential to prevent hemolysis?
- G6PD level (Correct answer)
- Serum calcium
- TSH
- Prolactin
Correct answer: G6PD level
G6PD deficiency predisposes to dapsone-induced hemolytic anemia, so it must be checked first.
ABD Reading 3
A patient presents with a tense subepidermal blister and linear IgG along the basement membrane on direct immunofluorescence.
What is the diagnosis?