Toxic epidermal necrolysis and Stevens-Johnson syndrome

Stevens-Johnson syndrome (SJS) was first described in 1922, as an acute mucocutaneous syndrome in two young boys. The condition was characterized by severe purulent conjunctivitis, severe stomatitis with extensive mucosal necrosis, and purpuric macules. It became known as SJS and was recognized as a severe mucocutaneous disease with a prolonged course and potentially lethal outcome that is in most cases drug-induced, and should be distinguished from erythema multiforme (EM) majus. Recent clinical studies have shown that the term 'EM majus' should not be used to describe SJS as they are distinct disorders [1-4].In 1956, Alan Lyell described four patients with an eruption resembling scalding of the skin which he called toxic epidermal necrolysis or TEN [4]. It was only as more patients with TEN were reported in the years following Lyell's original publication, that it became clear that TEN was drug induced, and that certain drugs such as sulfonamides, pyrazolones, barbiturates, and antiepileptics were the most frequent triggers of TEN. Increasingly to date, SJS and TEN are considered to be two ends of a spectrum of severe epidermolytic adverse cutaneous drug reactions, differing only by their extent of skin detachment.SJS and TEN are rare diseases in absolute numbers with an incidence of 1.89 cases of TEN per million inhabitants per year reported for Western Germany and Berlin in 1996 [5]. La Grenade et al report similar results, with 1.9 cases of TEN per million inhabitants per year based on all cases reported to the FDA AERS database in the USA [6]. Lower incidence rates were reported by Chan et al in Singapore [7]. Certain infectious diseases may have an impact on the incidence of TEN, and this is clearly the case for HIV where the annual incidence is approximately 1000-fold higher than in the general population, with approximately 1 case per thousand per year in the HIV-positive population ([8]. In a study of HIV positive patients of the greater Paris area in the