Cutaneous Drug Reactions

Question 1

Describe exanthematous drug eruptions

Answer 1

Delayed (T cell mediated) widespread pruritic rash

4-21days after drug administration

Question 2

What drugs cause exanthematous eruptions?

Answer 2

Penicillins
Sulphonamide antibiotics
Erythromycin
Allopurinol
Carbamazepine
NSAIDs
Phenytoin
Chloramphenicol

Question 3

What are the mechanisms of urticarial eruptions, and what drugs commonly cause them?

Answer 3

IgE-mediated reaction on secondary exposure
B-lactam ABx, carbamazepine, many others

Direct mast cell degraulation on first exposure
Aspirin, opiods, NSAIDs, muscle relaxants, vancomycin, quinolones

Question 4

Which drugs can induce acne?

Answer 4

Glucocorticoids
Androgens
Lithium
Isoniazid
Phenytoin

Question 5

Which drugs can induce bullous pemphigoid?

Answer 5

ACEi
Furosemide
Penicillin

Question 6

Which drugs can induce linear IgA disease?

Answer 6

Vancomycin

Question 7

Name characteristics of a fixed drug eruption

Answer 7

Erythematous pruritic plaques on hands, genitalia and lips

Resolve with persistent pigmentation when drug stopped

Question 8

What drugs commonly cause a fixed drug eruption?

Answer 8

Tetracycline
Doxycycline
Paracetamol
NSAIDs
Carbamazepine

Question 9

Which drugs can induce Stevens Johnson Syndrome or Toxic Epidermal Necrolysis

Answer 9

Sulphonamide ABx
Cephalosporins
Carbamazepine
Phenytoin
NSAIDs
Tramadol

Question 10

Which drugs can induce cutaneous photosensitivity and how do they manifest?

Answer 10

Amiodarone - immediate prickling with delayed erythema
Quinine, thiazides - exaggerated sunburn
Ca channel blockers - exaggerated telangectasia
Tetracyclines, Naproxen, Amiodarone - increased skin fragility