Stevens-Johnson syndrome and toxic epidermal necrolysis is a disorder of immune complexmediated hypersensitivity that is a severe expression of erythema multiforme, typically involving the skin, oral cavity, eyes and genitals. It is caused by many drugs, infections and malignant tumors. Its pathogenesis is still partially unknown, and no specific treatment has been shown to be clearly beneficial, therefore, the best treatment is early diagnosis, withdrawal of the suspect drug and support therapy. INTRODuCCION