Epidermal necrolysis: 60 years of errors and advances

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare conditions characterized by extensive epidermal detachment and mucositis. Both are associated with a high mortality rate and significant long-term morbidity. Since the initial report introducing the term TEN in 1956, diagnosis of the condition has been fraught with difficulties that continue to exist today. The terms 'erythema multiforme major' (EMM) and SJS, and their relationship to TEN have also been confusing to clinicians. It is now recognized that EMM is a different entity from SJS and TEN in terms of demographics, causality and severity. SJS and TEN represent a continuum of disease, and differ only by the extent of epidermal detachment and therefore severity. The term 'epidermal necrolysis' (EN) is used in this article to describe the spectrum of disease that includes SJS and TEN. Important advances in understanding the pathomechanism and treatment of EN have been made over the years. These include the recognition of human leucocyte antigen (HLA) associations (e.g. HLA-B*1502 with carbamazepine-induced TEN) and understanding of the pathogenic roles of drug-specific cytotoxic T cells and granulysin. It was previously believed that widespread keratinocyte death in EN is predominantly mediated by soluble Fas-ligand and that intravenous immunoglobulin therapy is useful in blocking this mechanism with resultant survival benefits. Further studies have since proven these theories to be incorrect. This short review describes the key advances in the terminology, classification, causality and treatment of EN, and identifies future priorities and challenges in the understanding and management of this condition.