Toxic Epidermal Necrolysis

Topic Name Introduction Pathophysiology Clinical Features Diagnosis Management Complications & Outcomes Prevention & Follow-up

Toxic Epidermal Necrolysis (TEN)

Overview

TEN represents the most severe form of adverse cutaneous drug reactions, characterized by extensive epidermal detachment and mucosal involvement. It exists on a spectrum with Stevens-Johnson Syndrome (SJS).

Key Points

• Incidence: 0.4-1.9 cases per million person-years
• Mortality rate: 25-35% in children
• BSA involvement: >30% epidermal detachment
• Gender distribution: Slight female predominance
• Age: Can affect any age, but rare in infants

Disease Spectrum

• SJS: <10% BSA involvement
• SJS/TEN overlap: 10-30% BSA involvement
• TEN: >30% BSA involvement

Pathophysiological Mechanisms

Immunological Mechanisms

• Drug-Specific Immune Response
  • CD8+ T cell-mediated cytotoxicity
  • Release of granulysin, perforin, and granzyme B
  • Fas-FasL mediated keratinocyte apoptosis
• Genetic Susceptibility
  • HLA associations:
    • HLA-B*15:02 (carbamazepine)
    • HLA-B*58:01 (allopurinol)
    • HLA-B*57:01 (abacavir)

Common Triggering Medications

• High Risk
  • Sulfonamide antibiotics
  • Anti-epileptics (carbamazepine, phenytoin, lamotrigine)
  • Allopurinol
  • Oxicam NSAIDs
  • Nevirapine
• Moderate Risk
  • Other antibiotics (β-lactams, macrolides)
  • Other NSAIDs
  • Other anticonvulsants

Clinical Manifestations

Prodromal Phase (1-3 days)

• Fever
• Malaise
• Upper respiratory symptoms
• Conjunctivitis
• Pharyngitis

Acute Phase

• Cutaneous Manifestations
  • Painful erythematous macules
  • Target-like lesions
  • Rapid progression to bullae
  • Nikolsky sign positive
  • Large sheets of epidermal detachment
• Mucosal Involvement (90% cases)
  • Oral mucosa (earliest)
  • Ocular surface
  • Genital mucosa
  • Respiratory epithelium
  • GI tract

Systemic Manifestations

• Severe pain
• High-grade fever
• Tachycardia
• Hypotension
• Multi-organ involvement

Diagnostic Approach

Clinical Assessment

• Detailed History
  • Medication exposure (previous 8 weeks)
  • Timeline of symptoms
  • Prior drug reactions
  • Recent infections
• Physical Examination
  • BSA involvement calculation
  • Mucosal assessment
  • Nikolsky sign testing
  • Vital signs monitoring

Laboratory Studies

• Essential Tests
  • Complete blood count
  • Comprehensive metabolic panel
  • Coagulation profile
  • Blood cultures
  • Skin cultures
• Histopathology
  • Full-thickness epidermal necrosis
  • Subepidermal split
  • Minimal dermal inflammation

Severity Assessment

• SCORTEN Score
  • Age >40 years
  • Heart rate >120/min
  • Cancer/hematologic malignancy
  • BSA involved >10%
  • Serum urea >10 mmol/L
  • Serum glucose >14 mmol/L
  • Serum bicarbonate <20 mmol/L

Treatment Protocol

Immediate Actions

• Discontinue causative drug
• Transfer to burn unit/ICU
• Isolation precautions
• Temperature control (30-32°C)

Supportive Care

• Fluid and Electrolyte Management
  • Modified Brooke's formula
  • Regular electrolyte monitoring
  • Albumin replacement if needed
• Wound Care
  • Sterile handling
  • Non-adherent dressings
  • Regular assessment
  • Topical antimicrobials
• Pain Management
  • Opioid analgesia
  • Anxiolytics for procedures

Specific Treatments

• First-Line Options
  • IVIG (2g/kg total dose)
  • Cyclosporine (3-5 mg/kg/day)
• Other Options
  • Systemic corticosteroids (controversial)
  • TNF-α inhibitors
  • Plasmapheresis

Specialist Care

• Ophthalmology
• Pulmonology
• Gynecology
• Nutrition
• Psychology

Complications and Outcomes

Acute Complications

• Sepsis
  • Leading cause of death
  • Regular screening essential
• Multi-organ Failure
  • Respiratory failure
  • Acute kidney injury
  • DIC
• Thermal Dysregulation
• Protein Loss

Long-term Sequelae

• Ocular
  • Symblepharon
  • Dry eyes
  • Visual impairment
• Cutaneous
  • Scarring
  • Pigmentation changes
  • Nail dystrophy
• Other Systems
  • Dental problems
  • Genital adhesions
  • Bronchiolitis obliterans

Prevention and Follow-up

Preventive Strategies

• Genetic Screening
  • HLA testing before high-risk medications
  • Family counseling
• Medication Safety
  • Avoiding trigger medications
  • Cross-reactivity awareness
  • Medical alert bracelet

Follow-up Care

• Regular Monitoring
  • Ophthalmology follow-up
  • Growth monitoring
  • Psychological support
• Quality of Life Assessment
• Vaccination Planning

Disclaimer

The notes provided on Pediatime are generated from online resources and AI sources and have been carefully checked for accuracy. However, these notes are not intended to replace standard textbooks. They are designed to serve as a quick review and revision tool for medical students and professionals, and to aid in theory exam preparation. For comprehensive learning, please refer to recommended textbooks and guidelines.