What are the diagnostic tests and immediate actions for a suspected case of Stevens Johnson syndrome?

Diagnostic Tests and Immediate Actions for Suspected Stevens-Johnson Syndrome

Patients with suspected Stevens-Johnson syndrome (SJS) should be immediately referred to a specialized multidisciplinary team and admitted to a burn center or ICU with experience in treating SJS/TEN if epidermal detachment exceeds 10% of body surface area. 1

Initial Diagnostic Assessment

History Taking

• Document prodromal symptoms: fever, malaise, upper respiratory symptoms 1
• Record date of rash onset and progression 1
• Ask about respiratory symptoms: cough, dyspnoea, bronchial hypersecretion 1
• Document gastrointestinal symptoms: diarrhea, abdominal distension 1
• Determine index date (first symptom onset) 1
• Record all medications taken in previous 2 months, including OTC and complementary therapies 1, 2
• Document previous drug allergies 1

Physical Examination

• Assess vital signs and oxygen saturation 1
• Document extent of skin involvement:
  • Epidermal detachment percentage (determines SJS vs TEN classification) 3
  • Presence of target lesions, purpuric macules, blisters 1
  • Mucosal involvement (eyes, mouth, genitalia) 1
• Calculate SCORTEN score within 24 hours to predict mortality risk 2:

  Points	Predicted Mortality (%)
  0	1
  1	4
  2	12
  3	32
  4	62
  5	85
  6-7	95-99

Essential Diagnostic Tests

1. Skin Biopsy - Critical for diagnosis 1

   • Histopathological features: epidermal damage ranging from individual cell apoptosis to confluent necrosis
   • Basal cell vacuolar degeneration and subepidermal vesicle/bulla formation
   • Mild perivascular lymphocytic infiltrate in dermis

2. Laboratory Tests

   • Complete blood count with differential
   • Comprehensive metabolic panel (renal/liver function)
   • Electrolytes, glucose, bicarbonate (for SCORTEN) 2
   • Blood cultures if infection suspected 1
   • Bacterial swabs from three areas of lesional skin 2

3. Ophthalmological Examination

   • Must be performed within 24 hours by an ophthalmologist 2
   • Assess for conjunctival hyperemia, pseudomembrane formation, epithelial defects 1

4. Chest Imaging

   • Chest X-ray to assess for pulmonary involvement

Immediate Actions

1. Stop Suspected Culprit Drug Immediately 1, 2

   • High-risk medications: allopurinol, carbamazepine, lamotrigine, sulfonamides, NSAIDs, phenytoin 2, 3

2. Transfer to Specialized Care

   • Patients with >10% BSA epidermal detachment require immediate transfer to burn center or ICU with SJS/TEN experience 1, 2
   • Barrier-nurse in side room with controlled humidity and temperature (25-28°C) 1

3. Wound Management

   • Leave detached epidermis in situ as biological dressing 2
   • Decompress blisters by puncture and fluid expression 2
   • Apply non-adherent dressings (Mepitel or Telfa) to denuded areas 2
   • Apply emollients to intact skin 1
   • Gentle cleaning with sterile water/saline or dilute chlorhexidine (1/5000) 2

4. Supportive Care

   • Fluid replacement based on body weight/affected BSA 2
   • Early enteral nutrition 2
   • Pain management with appropriate analgesia 2
   • Temperature control (ambient 25-28°C) 1, 2
   • Monitor for signs of sepsis (confusion, hypotension, decreased urine output) 2

5. Mucosal Care

   • Ocular: Two-hourly application of non-preserved lubricants 1
   • Oral: Antiseptic oral rinses twice daily (1.5% hydrogen peroxide or 0.2% chlorhexidine) 1
   • Urogenital: Apply white soft paraffin ointment every 4 hours 1

Pitfalls to Avoid

• Delayed diagnosis: SJS/TEN is a true medical emergency - early recognition and prompt management are lifesaving 4
• Misdiagnosis: Consider differential diagnoses (erythema multiforme major, pemphigus, bullous pemphigoid) 1
• Prophylactic antibiotics: Use only if clinical signs of infection develop 2
• Overlooking ocular involvement: Can lead to severe long-term sequelae even in mild cases 2
• Inadequate temperature control: Can lead to thermoregulatory dysfunction 2
• Rough handling of skin: Minimize shearing forces to prevent additional epidermal detachment 1

By following this diagnostic and management approach, clinicians can optimize outcomes for patients with this potentially life-threatening condition.