Stevens-Johnson Syndrome

Background
First described in 1922, Stevens-Johnson syndrome (SJS) is an immune-complex–mediated hypersensitivity complex that is a severe expression of erythema multiforme. It is known by some as erythema multiforme major, but disagreement exists in the literature. Most authors and experts consider SJS and toxic epidermal necrolysis (TEN) different manifestations of the same disease. For that reason, many refer to the entity as SJS/TEN. SJS typically involves the skin and the mucous membranes. While minor presentations may occur, significant involvement of oral, nasal, eye, vaginal, urethral, GI, and lower respiratory tract mucous membranes may develop in the course of the illness. GI and respiratory involvement may progress to necrosis. SJS is a serious systemic disorder with the potential for severe morbidity and even death. Missed diagnosis is common.
Although several classification schemes have been reported, the simplest breaks the disease down as follows:1
SJS - A "minor form of TEN," with less than 10% body surface area (BSA) detachment
Overlapping SJS/TEN - Detachment of 10-30% BSA
TEN - Detachment of more than 30% BSA

Pathophysiology
SJS is an immune-complex–mediated hypersensitivity disorder that may be caused by many drugs, viral infections, and malignancies. Cocaine recently has been added to the list of drugs capable of producing the syndrome. In up to half of cases, no specific etiology has been identified.
Pathologically, cell death results causing separation of the epidermis from the dermis. The death receptor, Fas, and its ligand, FasL, have been linked to the process. Some have also linked inflammatory cytokines to the pathogenesis.
Frequency
United States
Cases tend to have a propensity for the early spring and winter.
International
SJS occurs with a worldwide distribution similar in etiology and occurrence to that in the United States.
Mortality/Morbidity
Mortality is determined primarily by the extent of skin sloughing. When BSA sloughing is less than 10%, the mortality rate is approximately 1-5%. However, when more than 30% BSA sloughing is present, the mortality rate is between 25% and 35%.
See SCORTEN for a more complete discussion of severity of illness and mortality.
Lesions may continue to erupt in crops for as long as 2-3 weeks. Mucosal pseudomembrane formation may lead to mucosal scarring and loss of function of the involved organ system. Esophageal strictures may occur when extensive involvement of the esophagus exists. Mucosal shedding in the tracheobronchial tree may lead to respiratory failure.
Ocular sequelae may include corneal ulceration and anterior uveitis. Blindness may develop secondary to severe keratitis or panophthalmitis in 3-10% of patients. Vaginal stenosis and penile scarring have been reported. Renal complications are rare.

Race
A Caucasian predominance has been reported.
Sex
The male-to-female ratio is 2:1.
Age
Most patients are in the second to fourth decade of their lives; however, cases have been reported in children as young as 3 months.
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