Stevens-Johnson syndrome and toxic epidermal necrolysis are rare and possibly fatal adverse skin reactions that are most commonly caused by certain medications. SJS/TEN are most often induced by antibiotics, anticonvulsants, NSAIDs and allopurinol. Some cases of these conditions can be caused by infections such as Mycoplasma pneumoniae, HIV and HSV, as well as malignant diseases and idiopathic states. SJS and TEN are considered to be the same disease varying only in the extent of skin detachment. SJS is defined as skin involvement of <10%, TEN is defined as skin involvement of >30%, and SJS/TEN overlap as 10–30% skin involvement. SJS/TEN is thought to be a T-cell-mediated disorder. Nowadays there are three hypotheses on T cell activation: the hapten/pro-hapten model, the pharmacological interaction concept, and the altered peptide model. Usually SJS / TEN begin with prodromal symptoms such as fever and malaise. Cutaneous lesions typically occur a few days after development of prodromal symptoms and present as erythema, ill-defined macules and atypical targetoid lesions. Cutaneous changes are usually found on the presternal region and proximal end of extremities. In most cases mucous membranes are affected as well, usually characterized by erythema followed by painful erosions. Some patients suffer from systemic manifestations, especially with gastrointestinal, respiratory and renal symptoms. The diagnosis is grounded on information gained during history taking, the clinical assessment as well as histopathological findings. The initial management of SJS/TEN is based on prompt withdrawal of suspected causative drug in conjunction with supportive care.