Toxic Epidermal Necrolysis (TEN)

Question 1

Definition

Answer 1

• TEN is the more severe form (>30% body surface area) or Stevens-Johnson Syndrome (SJS) which is a severe skin detachment with mucocutaneous complications. It is an immune reaction to foreign antigens.

Question 2

Aetiology

Answer 2

• Infection
  
  • URTI
  • Pharyngitis
  • Otitis media
  • Mycoplasma pneumoniae
  • Herpes
  • EBV
  • CMV
• Vaccination
  
  • Smallpox
• Medicine
  
  • Antibiotics (i.e. aminopenicillins, quinolones, cephalopsporins)
  • Antiretrovirals
  • Anticonvulsants (i.e. carbamazepine, phenytoin)
  • NSAIDs
  • Analgesics (i.e. paracetamol)

Question 3

Signs & Symptoms

Answer 3

• Signs/symptoms include rash, mucosal involvement and Nikolsky’s sign.
• Risk factors include anticonvulsant medications, recent infection, recent antibiotic use, SLE, HIV, radiotherapy, HLA and genetic predisposition and smallpox vaccination.

Question 4

Pathophysiology

Answer 4

• Detachment of the epidermis from the papillary dermis at the epidermal-dermal junction
• Manifests as a papulomacular rash and bullae as a result of keratinocyte apoptosis mediated by cytotoxic T-lymphocytes and plasma TNG-alpha and IFN gamma.

Question 5

Investigation

Answer 5

• Skin biopsy
  
  • Keratinocyte apoptosis with detachment
• Blood cultures
  
  • Negative in SJS/TEN
• FBC
  
  • Depend on stage but may have elevated WBC
• Urea
  
  • Elevated
• LFTs
  
  • Variable
• ABG
  
  • Hypoxaemia
  • Acidosis

Question 6

Treatment

Answer 6

• Urgent evaluation + withdrawal of causative agent
• Steroids
• IVIG
• Immunosuppresants
• Dressings
• Topical antibacterial agents (i.e. bacitracin)
• Emollients
• Ophthalmological examination
• IV fluids + nutritional support
• Oral hygiene
• Analgesia

Question 7

Complications

Answer 7

• Infection
• Ocular complications (i.e. conjunctivitis)
• Abnormal skin pigmentation
• Acute compartment syndrome
• Nail plate loss
• Acute liver failure
• Acute renal failure
• Hypothermia
• Vaginal synechiae
• Pulmonary complications (i.e. bronchitis)
• Ureteral perforation

Question 8

Prevention and prognosis

Answer 8

• Secondary prevention
  
  • Avoid use of precipitant medicines
  • Be alert to any mucosal erosions or ulcerations or rash development
• Prognosis
  
  • Best when <50 years of age, TBSA is low, transferred to burn centre, no sepsis and don’t require antibiotics.
  • SJS mortality 1-5%
  • TEN mortality 25-35%