Derm - Stevens-Johnsons Syndrome And Toxic Epidermal Necrolysis

Question 1

Defintion

Answer 1

Severe systemic cutaneous adverse hypersensitivity reactions, characterised by epidermal necrosis and detachment.
- Most commonly due to medication

Question 2

Classification

Answer 2

The disease is classified by the extent of body surface area involved:
- SJS < 10%
- SJS/TEN overlap: 10-30%
- TEN >30%

Question 3

Epidemiology and Risk factors

Answer 3

Medications:
- sulfa drugs,
- penicillins,
- cephalosporins,
- antiepileptics (lamotrigine, carbamazepine, phenytoin),
- allopurinol,
- NSAIDs,
- oral contraceptive pill
Infections: examples include Mycoplasma pneumoniae, HIV
Sex: females

Question 4

Signs

Answer 4

• Erythematous or purpuric macules, rapidly evolving into widespread blistering and desquamation
• Mucosal involvement
• Nikolsky sign: when lateral pressure is applied, the epidermis separates, resulting in blistering and erosions
• Pyrexia
• Tachycardic

Question 5

Symptoms

Answer 5

Symptom onset typically ~ 3 weeks from onset of medication:
- Fever, malaise, headaches, keratoconjunctivitis: typically prodromal, lasting few days before onset of rash
- Sore throat and eyes

Question 6

Diagnosis

Answer 6

FIRST LINE + GOLD STANDARD: Skin biopsy
- confirms diagnosis by showing full-thickness epidermal keratinocytes necrosis and minimal dermal inflammation
Serum granulysin: elevated levels, measure within the first few days of drug eruption

Investigations to consider:
- FBC, CRP, blood cultures - exclude staph scalded skin syndrome
- U+E = dehydration and pre-renal AKI

Question 7

Scoring scale for patient mortality

Answer 7

SCORTEN or ABCD 10

Question 8

Treatment

Answer 8

FIRST LINE:
- Withdrawal of causative drug
- Hospital admission
- Supportive care:
= fluid, electrolyte management,
= temperature regulation,
= wound care and nutritional support in ICU or burns unit
- Analgesia
- IV immunoglobulin

SECOND LINE:
- Immunosuppressant e.g. ciclosporin or cyclophosphamide
- systemic corticosteroids
- plasmapheresis

Question 9

Complications

Answer 9

Secondary infection leading to sepsis
Dehydration
Electrolyte derangement
Renal failure
Acute respiratory distress syndrome
Thromboembolism and disseminated intravascular coagulopathy
Skin scarring, hypo- or hyper-pigmentation
Ocular complications: for example ulceration