Drug Eruptions

Question 1

Maculopapular Overview

Answer 1

Commonest type
Generalised erythematous macules and papules
+/- fever and increased eosinophils
Develops w/i 2/52 of drug onset
Pencillins, cephalosporins, anti-epileptics

Question 2

Urticaria Overview

Answer 2

Wheal +/- angioedema and anaphylaxis
Rapid onset after taking drug
Immune (IgE): penicillins, cephalosporins
Non-immune (direct mast cell degeneration): morphine, codeine, NSAIDs, contrast

Question 3

Erythema Multiforme Appearance

Answer 3

symmetrical target lesions on palms, soles and limbs
Occurs 1-2 weeks after insult
Infections are commoner cause of EM

Question 4

Erythema Multiforme Causes

Answer 4

Idiopathic
Infections: HSV, myocplasma
Drugs (SNAPP): Suphonamides, NSAIDs, Allopurinol, Penicillin, Phenytoin

Question 5

Steven-Johnson Syndrome Overview

Answer 5

More severe variant of EM

Blistering mucosa: conjunctiva, oral, genital

Question 6

Toxic Epidermal Necrolysis (TEN) Overview

Answer 6

Extreme form of SJS
Nearly always a drug reaction
Features: severe mucosal ulceration, widespread erythema followed by epidermal necrosis w/ loss of large sheets of epidermis, leads to dehydration
v v increased risk in HIV positive 
Rx: dexamethasone, IVIg
Mortality: 30%