Stevens-Johnson Syndrome (SJS)

A severe, potentially life-threatening mucocutaneous reaction characterized by extensive epidermal detachment and multisite mucosal erosions. Part of a spectrum with Toxic Epidermal Necrolysis (TEN), distinguished by extent of body surface area involvement.

Key Points

• BSA involvement: SJS <10%, SJS/TEN overlap 10-30%, TEN >30%
• Mortality rate: 5-10% (SJS), 30-50% (TEN)
• Most common in pediatric and elderly populations
• Strong genetic associations (HLA-B*15:02, HLA-B*58:01)
• Requires immediate hospitalization

Epidemiology

• Incidence: 1-6 cases per million person-years
• Higher risk in:
  • HIV-positive individuals
  • Cancer patients
  • Autoimmune disease patients
  • Specific ethnic groups (Asian populations)
• Peak incidence: bimodal (children and elderly)
• Slight female predominance

Prodromal Phase (1-3 days)

• Fever >39°C
• Malaise
• Upper respiratory symptoms
• Myalgia and arthralgia
• Anorexia

Acute Phase

• Cutaneous Manifestations:
  • Initial:
    • Dusky red macules
    • Target-like lesions
    • Painful skin
  • Progressive:
    • Vesicles and bullae
    • Nikolsky sign positive
    • Epidermal detachment
    • Skin tenderness
• Mucosal Involvement:
  • Oral mucosa (100% cases):
    • Painful erosions
    • Hemorrhagic crusting
    • Difficulty swallowing
  • Ocular (80% cases):
    • Conjunctivitis
    • Pseudomembrane formation
    • Corneal ulceration
  • Genital (40% cases):
    • Erosions
    • Dysuria
    • Urethritis

Systemic Manifestations

• Respiratory:
  • Bronchial erosions
  • Pneumonitis
  • Respiratory failure
• Gastrointestinal:
  • Hepatitis
  • GI bleeding
  • Diarrhea
• Renal:
  • Acute kidney injury
  • Prerenal azotemia

Immunologic Mechanisms

• Drug-Specific Immune Response:
  • T-cell mediated cytotoxicity
  • CD8+ T cell activation
  • Granulysin production
  • Fas-FasL interaction
• Molecular Events:
  • Keratinocyte apoptosis
  • Cytokine release:
    • TNF-α
    • IL-15
    • IFN-γ
  • Oxidative stress
  • Genetic susceptibility

Common Triggers

• Medications:
  • Anticonvulsants:
    • Carbamazepine
    • Phenytoin
    • Lamotrigine
  • Antibiotics:
    • Sulfonamides
    • Beta-lactams
    • Fluoroquinolones
  • NSAIDs
  • Allopurinol
• Infections:
  • Mycoplasma pneumoniae
  • Herpes simplex virus
  • HIV

Diagnostic Criteria

• Required Features:
  • Acute onset
  • Target lesions/Bullae
  • Epidermal detachment
  • Mucosal involvement
• Laboratory Studies:
  • Complete blood count
  • Comprehensive metabolic panel
  • Coagulation profile
  • Blood cultures
  • HLA typing (if indicated)
• Skin Biopsy:
  • Full-thickness epidermal necrosis
  • Subepidermal blistering
  • Minimal dermal inflammation

Severity Assessment

• SCORTEN Criteria:
  • Age >40 years
  • Heart rate >120/min
  • Cancer/hematologic malignancy
  • BSA detachment >10%
  • Serum urea >10 mmol/L
  • Serum glucose >14 mmol/L
  • Bicarbonate <20 mmol/L

Initial Approach

• Immediate Actions:
  • Discontinue causative drug
  • ICU/Burn unit admission
  • Fluid resuscitation
  • Temperature regulation
  • Pain management
• Supportive Care:
  • Wound care:
    • Sterile handling
    • Non-adherent dressings
    • Infection prevention
  • Nutritional support
  • Electrolyte management
  • Prevention of complications

Specific Treatments

• Systemic Therapy:
  • IVIG (2-3g/kg total over 3-5 days)
  • Corticosteroids (controversial)
  • Cyclosporine
  • TNF-α inhibitors
• Specialty Care:
  • Ophthalmology:
    • Hourly lubricants
    • Topical antibiotics
    • Membrane removal
  • Oral care:
    • Antiseptic mouthwashes
    • Topical anesthetics
  • Pulmonary care
  • Pain management

Acute Complications

• Sepsis
• Multi-organ failure
• Shock
• DIC
• Respiratory failure
• Acute kidney injury

Long-term Sequelae

• Ocular:
  • Symblepharon
  • Dry eyes
  • Visual impairment
  • Corneal scarring
• Cutaneous:
  • Scarring
  • Pigmentation changes
  • Nail dystrophy
  • Hair loss
• Other:
  • Dental problems
  • Vaginal adhesions
  • Bronchial stenosis
  • Psychological trauma

Preventive Strategies

• Genetic Screening:
  • HLA-B*15:02 before carbamazepine
  • HLA-B*58:01 before allopurinol
• Drug Management:
  • Avoid trigger medications
  • Cross-reactivity awareness
  • Slow drug titration
• Patient Education:
  • Early warning signs
  • Drug allergy documentation
  • Medical alert bracelet

Monitoring Guidelines

• Regular skin examination
• Temperature monitoring
• Early recognition of symptoms
• Long-term follow-up plan

Pediatric Considerations

• Higher risk of dehydration
• Different drug triggers
• Growth and development impact
• Psychological support needs

Pregnancy Considerations

• Higher mortality risk
• Fetal complications
• Modified treatment approach
• Long-term reproductive impact

Quality of Life Impact

• Psychological support
• Rehabilitation needs
• Social reintegration
• Occupational considerations