Epidemiology, Causes, Risk Factors
Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are both rare (estimated incidence rates for TEN of 0.4 to 1.2 cases per million person-years, and SJS of 1 to 6 cases per million person-years), but extremely severe and potentially life-threatening dermatological conditions. Mortality rates reported in large case series range from 25% to 50% (average, 25–35%) for TEN patients and approximately 5% for SJS patients (1-3).
In the vast majority (>80%) of patients, a strong association between drug ingestion and disease development is observed (other rare causes include infection and immunization).
Medications most frequently identified as causative agents of SJS/TEN include allopurinol, antibiotics, nonsteroidal anti-inflammatory drugs, and anticonvulsants. To date however, more than 100 drugs have been reported as being associated with SJS/TEN.
Although the precise sequence of molecular and cellular events underlying SJS and TEN is unfortunately insufficiently understood, it is known that certain patient groups are at increased risk of developing this disease. Risk factors include immunosuppression (e.g. AIDS patients have an about 1000-fold higher risk of developing TEN than the general population), and, for certain medications and ethnic groups, the presence of specific human leukocyte antigen alleles (e.g. HLA-B*1502 for carbamazepine in patients of Chinese descent).
The IRTEN prospective registry aims to provide more precise information concerning the epidemiology, causes (medications) and risk factors including analysis of regional/ethnic variability.