From the Guidelines
Erythema multiforme (EM) minor, EM major, toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and staphylococcal scalded skin syndrome (SSSS) are distinct dermatologic conditions that require prompt recognition and management to reduce morbidity and mortality, with the most critical aspect being supportive care, as emphasized in the British Association of Dermatologists' guidelines 1.
Key Differentiating Features
- EM minor presents with target lesions primarily on extremities, with minimal mucosal involvement, and is typically triggered by HSV infection.
- EM major shows more extensive skin involvement (up to 10% body surface area) with at least two mucosal sites affected.
- SJS involves less than 10% epidermal detachment with widespread purpuric macules or atypical target lesions and significant mucosal involvement.
- TEN presents with greater than 30% epidermal detachment, with SJS-TEN overlap occurring with 10-30% detachment.
- SSSS, caused by Staphylococcus aureus exfoliative toxins, presents with widespread erythema followed by superficial epidermal sloughing but spares mucous membranes.
Management and Treatment
- Discontinuing offending agents is crucial in managing SJS/TEN, as these conditions are often medication-induced, with common culprits including sulfonamides, anticonvulsants, allopurinol, and NSAIDs 1.
- Supportive care, including wound management, fluid balance, nutritional support, analgesia, and preventing life-threatening complications, is the mainstay of treatment for SJS/TEN, as highlighted in the guidelines for managing SJS/TEN in children and young people 1.
- IVIG or cyclosporine may be considered for SJS/TEN, while SSSS requires antibiotics targeting S. aureus.
- The use of an appropriate dressing on exposed dermis can reduce fluid and protein loss, limit microbial colonization, and help with pain control, as noted in the UK guidelines for the management of SJS/TEN in adults 1.
Prognosis and Mortality
- Mortality increases with age and extent of involvement, with TEN having the highest mortality rate (30-35%) 1.
- Long-term sequelae, particularly ophthalmic, mucocutaneous, and psychological, can be severely debilitating in survivors of SJS/TEN, emphasizing the importance of prompt and effective management 1.
From the Research
Erythema Multiforme Minor and Major
- Erythema multiforme (EM) is a cutaneous reaction pattern manifested by well-demarcated plaques on the trunk and extremities 2
- Target, or "iris," lesions, with central clearing, are characteristic of this disorder 2
- EM may be a mild condition (erythema multiforme minor), or it may be a severe, possibly life-threatening condition (erythema multiforme major or Stevens-Johnson syndrome) 2
Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)
- SJS and TEN are acute bullous disorders associated with different prognoses, mainly due to infections and drugs 3
- SJS and TEN are predominantly triggered by drugs, whereas EM is caused by infections (primarily herpes simplex virus and Mycoplasma pneumoniae) 4, 3
- TEN is manifested by widespread epidermal desquamation and is the most severe form of this disorder 2
Key Points for USMLE
- The clinical distinction between EM, SJS, and TEN had been subject to uncertainty and controversy for more than a century, but a consensus classification was published in 1993 4
- The SCORTEN (score of toxic epidermal necrolysis) can and should be used to assess disease prognosis in patients with SJS/TEN 4
- Supportive treatment is generally considered sufficient for EM, while SJS/TEN may require systemic therapy, although the type of therapy is still uncertain 4, 5
- Cyclosporine may be able to halt disease progression and lower mortality rates in SJS/TEN 4