Derm

Question 1

Which drugs are most likely to causes SJS/TEN

Answer 1

Antibiotics 40% of the time (penicillins, cephlosporins)
Paracetamol
NSAIDs (oxicam mostly)
Allopurinol
Anti epilleptics - carbamazepine, phenytoin, phenobarbitone
Sulfonamides - clotrimoxazole

> 200 medication triggers, more commonly sytemic medications with longer half lifes. TEN has been reported after topicals
No drug implicated 20% of the time

Question 2

What is the mechanism that SJS/TENS occurs

Answer 2

Drug specific CD8 cytoxic lymphocytes detected in early blister fluid that have natural killer cell acitivty and probably kill keratinocytes by direct contact

2 major pathways proposed
- Fas Fas ligand pathway where FasL secreted by blood lymphocytes bind to keratinocyte Fas ‘death’ receptor of keratinocytes
- Granule mediated exocytosis via perforin and granzyme B

Question 3

How does SJS/TEN present?

Answer 3

Between few dasy to 1 month after starting medication
Within 1st week after antibiotics
Up to 2 months for anticolvulsants

PRODROMAL ILLNESS - Flu like
- Fevers >39
- Sore throat/dysphagia
- Cough and coryza
- Sore red eye/conjunctivis
- General aches and pain

RASH
- Abrupt onset tender rash starting on trunk and extending rapidly over hours to days (rare on scalp, palms, soles). Max by 4days
- Diffuse macular or purpura
- Diffuse erythema
- Tagetoid
- Flaccid blisters that then merge to form sheets of detached skin
- Nikolsy sign positive

MUCOSAL INVOLVEMENT - prominent, severe with at least 2 surfaces
- Eyes: Conjunctivitis, anterior uveitis, panopthalmitis (re sore, sticky, photosensitivity)
- Lips/mouth: Cheilitis/somatitis (red, crusted, painful ulcers)
- Pharynx/oesophagu: Dysphagia
- Genitals and urinary tract - erosions, ulvers, retention
- Upper respiratory tract: cough and respiratory distress
- GI: diarrhoea

OVERALL
Very ill
Extremely anxious
Considerable pain
Organs (kidney, liver, bones marrow) may be effects

Question 4

What are the acute and chronic complications of SJS/TEN

Answer 4

ACUTE
- Mortaility 10% SJS and 30% TENS
- Dehydration and acute malnutrition
- Infections (skin, lungs, septiciemia)
- ARDS
- GI perforation or intussesception
- Multiorgan failure
- Thromboembolism and DIC

CHRONIC
- Pigment changes and scarring
- Lung disease - bronchiolitis, bronchiectasis
- Eye disease - blindness, ectropion/entropion
- Joint contractions

Question 5

How are SJS and TEN classified

Answer 5

SJS
<10% TBSA
Widespread erythematous or purpuric macules or flat atypical target

SJS/TEN Overlap
10-30% TBSA
Widespread purpuric macules or flat atypical targets

TEN with spots
>30% TBSA
Widespread purpuric macules or flat atypical targets

TEN without spots
>10% TBSA
Large epidermal sheets and no purpuric macules

Question 6

What are the differential diagnosis for SJS/TEN

Answer 6

Staph scalded skin or toxic shock syndrome
Erythema multiform major
DRESS
Pemphigus (drug induced or vulgaris)
Bullous pemphigoid

Question 7

What is SCORTEN

Answer 7

Scoring system to predict mortality of SJS/TEN

Age>40
Malignancy
HR>120
TBSA>10%
Urea>10
Glucose>14
Bicarb<20

Risk of dying
1 point - 3.2%
2 points - 12.1%
3 points - 35.3%
4 points - 58.3%
5 points >90%

Question 8

What is the management of SJS/TEN

Answer 8

• Cessation of causative organism
• ICU or burn unit admission (prevents infection, reduces hospital stay and improves survival rates)
• Sterile, nonstick dressings with topical antiseptics
• Fluid replacement and temperature maintenance
• Pain relief
• Eye, lung, urinary, genital care as needed
• DVT prophylaxis
• Psyche and PT

+/- sterois, ciclosporin, IVIG, plasmapheresis as per Dermatology

Question 9

What is DRESS and how does it present

Answer 9

Drug reaction with eosinophila and systemic symptoms starting 2-8 weeks after starting medication, typical triad is high fevers, extensive rash and organ involvement (think any itis)

Rash features (can last many weeks)
- 80% morbiliform of varying morphology with targetoid, blisters and pustules)
- Eryhroderma >90% TBSA in 10%
- Facial swelling in 30%
- Mucosal involvement in 25%

Other features
Haemotological abnormalities (eosinophilia 30%, anemia, thrombocytopenia) Lymphadenopath

Question 10

Who is at risk of DRESS and what is the main pathophysiology

Answer 10

Delayed T cell mediated reaction with suspected genetic predisposition (1st degree relatives also at risk), reactivation of HHV6 and EBV and liver metabolism defects being responsible

Antipsychotics (carbamazepine, phenytoin. 1 in 10 000 chance)
Allopurinol - dose, kidney injury and thiazides increase risk
Sulphanomide antibiotics (bactrim)
Olanzapine

If within 2 weeks, then think betalactam antibiotics and iodoinated contrast. >2 weeks for antiepileptics and allopurino

10% no causative drug

Question 11

What are the main causes of death from DRESS

Answer 11

Acute liver failure with coagulation dysfunction and encephalopathy
Fulimant myocarditis
Haemophagocytosis
Multiorgan failure

Question 12

What is the management of DRESS

Answer 12

Cessation of causative agent
Supportive treatment: Dressing with topical emollients and steroids, antihistamines)
Fluid and electrolyte replacement
Warming
Systemic steroids, particularly with exfoliative dermatitis, pneumonitis and hepatitis

IVIG, plasmapheresis, immundoulatory drugs in consultation with Derm