Stevens-Johnson syndrome is a mucocutaneous immune-mediated hypersensitivity reaction. It is often triggered by drugs or infections. It presents as a skin and mucous membrane drug hypersensitivity reaction with variable severity.
Stevens-Johnson syndrome (SJS) is a mild variant that affects less than 10% of the body surface area whereas toxin epidermal necrolysis is a potentially life-threatening severe form that involves more than 30% of the body surface area. The estimated incidence of SJS is one to six cases per million person-years.
The main etiology is drug induced in about 75% of cases,