Drug Eruptions and SJS

Question 1

What are the presentations of cutaneous drug eruption?

Answer 1

1. Maculopapular or morbiliform rash - 46%
2. Urticaria and angioedema - 25%
3. Fixed drug eruptions - 10%
4. Erythema multiforme - 5%
5. Stevens-Johnson syndrome - 4%
6. Exfoliative dermatitis - 4%
7. Photosensitivity reactions - 3%
8. Anaphylaxis - 1.5%
9. Toxic epidermal necrolysis (TEN) - 1.3%

Question 2

How do you evaluate suspected drug reaction?

Answer 2

1. Previous experience or relative reaction rates of drug
2. Rule out alternative etiologies unrelated to drug
3. Timing and onset (within 1-2 weeks initiation of therapy)
4. Drug levels
5. Reaction to discontuining drug
6. Response to rechallenge

Question 3

What are the difference between erythema multiforme, Stevens-Johnson syndrome and TEN?

Answer 3

Spectrum of severity

Erythema multiforme
- targetoid skin lesion in absence of systemic illness or severe mucosal disease

SJS
- Widespread targetoid lesions, flat and atypical, confluent and develop large areas of blisters and epidermis detachment
- Purpuric
- Fever and systemic symptoms
- Affecting < 30% BSA

TEN
- Blistering with extensive skin detachment
- Cell poor, necrotic keratinocytes without satellite cell necrosis
- Affecting > 30% BSA

Question 4

What are the common causes associated with SJS?

Answer 4

Allopurinol
Amoxicillin, ampicillin
Anticonvulsants, barbiturates, phenobarbital, phenytoin
Carbamazepine
Gold
NSAIDs
Sulfonamides
Myoplasma pneumoniae

Question 5

TEN is one of the most severe cutaneous drug eruptions.
The skin is initially __ and __, quickly _____ like “wet wallpaper”
Progresses very __, with 1 in 7 patients losing entire epidermis within __
Mortality rate of _____, most deaths are related to __

Mainstay of treatment is to __, __, __, __
Postulated treatments include __, __, __

Answer 5

Erythematous and tender, sloughs off in large sheets

Very rapidly, within 24 hours

Mortality rate of 11-35%

Mainstay of treatment:
1. Discontinue all likely offending drugs
2. Transfer to burn unit or ICU
3. Aggressive fluid hydration (Parkland formula)
4. Monitor and treat secondary infection

Postulated treatment:
1. Systemic corticosteroids
2. TNF-a inhibitor
3. IVIG

Question 6

SJS/TEN is associated with HLA __ which is common in __

Chronic medications that is important for HLA identification: (2)

Answer 6

HLA-B*1502, Han Chinese

Allopurinol, carbamazepine