Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens-Johnson/toxic epidermal necrolysis(SJS/TEN), it forms a spectrum of disease, with SJS being less severe. Early symptoms of SJS include fever and flu-like symptoms. A few days later the skin begins to blister and peel forming painful raw areas. Mucous membranes, such as the mouth, are also typically involved.[2]Complications include dehydration, sepsis, pneumonia, and multiple organ failure. The most common cause is certain medications such as lamotrigine, carbamazepine, allopurinol, sulfonamide antibiotics, and nevirapine. Other causes can include infections such as Mycoplasma pneumoniae and cytomegalovirus or the cause may remain unknown.Risk factors include HIV/AIDS and systemic lupus erythematosus. The diagnosis is based on involvement of less than 10% of the skin. It is known as TEN when more than 30% of the skin is involved and an intermediate form with 10 to 30% involvement. SJS/TEN reactions are believed to follow a type IV hypersensitivitymechanism. It is also included with drug reaction with eosinophilia and systemic symptoms (DRESS syndrome), acute generalized exanthematous pustulosis(AGEP), and toxic epidermal necrolysis in a group of conditions known severe cutaneous adverse reactions (SCARs). Erythema multiforme (EM) is generally considered a separate condition. @medicalcortex