II. Definitions
- Erythema Multiforme Major
- Stevens Johnson Syndrome (SJS)- Affects <10% of body surface area
 
- SJS-TEN Overlap- Affects 10-30% of body surface area
 
- Toxic Epidermal Necrolysis (TEN)- Affects 30% of body surface area
 
III. Pathophysiology
- Severe clinical variant of Erythema Multiforme
- Previously thought to be part of same spectrum as Erythema Multiforme Minor- Now thought to be clinically distinct
 
IV. Epidemiology
- Most common in winter and early spring
- More common in adult women, but affects children of either gender equally
- 
                          Incidence U.S.- Stevens Johnson Syndrome: 1 to 7 per million people per year
- Toxic Epidermal Necrolysis: 0.4 to 1.5 per million people per year
 
V. Causes
- See Erythema Multiforme Causes
- 
                          Drug-Induced Skin Reactions are the most common cause of erythema mutiforme major- Contrast with Erythema Multiforme Minor which is most often due to infection (esp. HSV, Mycoplasma)
- Medications cause 50% of Stevens Johnson cases
- Medications cause 90% of Toxic Epidermal Necrolysis cases
- Highest risk with higher doses and rapid drug introduction
- Most common with Trimethoprim-Sulfamethoxazole (Bactrim)- Risk with Trimethoprim-Sulfamethoxazole is up to 40 fold higher in HIV Infection
 
 
VI. Symptoms
VII. Signs
- Patient may appear toxic (esp. Toxic Epidermal Necrolysis)
- Pathognomonic target lesions- Widespread skin involvement
- See Erythema Multiforme for course and specific description
 
- Lesion distribution- Starts on face and trunk and spreads peripherally
- Typically symmetrical
 
- Epidermal detachment- Affects >30% BSA in Toxic Epidermal Necrolysis (<10% BSA in Stevens-Johnson)
- Positive Nikolsky Sign in both Stevens-Johnson and Toxic Epidermal Necrolysis
 
- Mucosal bullae to erosions (severe in 20% of cases)- Oral Mucosal involvement is most common (genital and ocular involvement may also occur)
- Mucosal lesions start as red, edematous lesions that progress to superficial erosions with pseudomembrane
- Oral Mucosa may lead to inadequate oral intake (due to painful Oral Ulcers)
- Respiratory bullae may lead to respiratory distress or Respiratory Failure
 
- Ocular involvement (30% of children, 70% of adults)- May cause Conjunctivitis, Keratitis, Endophthalmitis
 
VIII. Differential Diagnosis
IX. Diagnosis
- Clinical diagnosis
- Skin biopsy confirms the diagnosis- Apoptosis and necrosis
- Keratinocyte vacuolization
- Dermal-epidermal separation
- Perivascular Lymphocyte infiltration
 
X. Complications
- Secondary Skin Infections and Sepsis (Staphylococcus Aureus, Pseudomonas)- Similar to serious burn injuries, with infectious and fluid balance complications
- Most common cause of death
 
- Pulmonary involvement (Hypoxemia, hypercarbia, Respiratory Failure)
- Renal involvement (Acute Glomerulonephritis, Acute Renal Failure)
- Corneal scarring (related to Corneal Ulceration)
- Gastrointestinal conditions (ileus, Acute Hepatitis, hepatocellular necrosis)
XI. Labs
- No lab tests are specific for Stevens Johnson Syndrome
XII. Management
- Withdraw all potential causative agents
- 
                          Intensive Care unit (or burn unit) admission for SCORTEN Score >2- Burn Unit recommended for >10% involvement
 
- Supportive care- Fluid Resuscitation with 2 ml/kg/BSA%
- Nutritional Support
- Opioid Analgesics are typically required
- Wound care
- Antibiotics only where specifically indicated
- Avoid Systemic Corticosteroids (use not supported by evidence)
- Oral Ulcer symptomatic management
 
- Specific immunologic agents that have been used by specialists in stevens-johnson and TEN
- Other measures- Ophthalmology consult for eye involvement (Corneal dehiscence)
- Rewetting drops
 
XIII. Prognosis
- See SCORTEN Score
- Mortality due to Sepsis, multi-organ failure- Stevens Johnson: 1-3%
- Toxic Epidermal Necrolysis: 30-50%
 
XIV. Prevention
- 
                          Patient Education when prescribing drugs associated with Stevens-Johnson- Immediately stop suspected drug (see causes above) if symptoms suggestive of Stevens-Johnson
- Skin pain, redness or Blister development with systemic symptoms (e.g. fever, Pharyngitis)
- Seek medical attention and do not reintroduce the suspected medication
- (2013) Presc Lett 20(10): 59
 
XV. References
- (2024) Presc Lett 31(7): 37-8
- Behar and Claudius in Herbert (2020) EM:Rap 20(7): 8-9
- Long (2016) Crit Dec Emerg Med 30(7):3-10
- Mockenhaupt (2008) J Invest Dermatol 128(1):35-44 [PubMed]
- Parrillo (2007) Curr Allergy Asthma Rep 7(4): 243-7 [PubMed]
- Trayes (2019) Am Fam Physician 100(2): 82-8 [PubMed]
- Usatine (2010) Am Fam Physician 82(7): 773-80 [PubMed]
