DRESS (drug reaction with Eosinophilia and systemic symptoms) is a syndrome classically considered as a severe cutaneous drug adverse reaction. But visceral manifestations (renal, liver, lung, heart...) may be at the forefront. It presents clinically as an exanthema evolving to erythroderma with facial edema, associated with lymphadenopathy, high fever, visceral involvement (hepatitis, renal failure, pneumonitis, or hemophagocytic syndrome), eosinophilia preceded by lymphopenia and/or atypical lymphocytes. DRESS is characterized by a long delay between the first drug intake and its development (2 weeks to 3 months) and by its long course (more than 2 weeks) with flares even after drug discontinuation. Its pathophysiology is unique: it is the consequence of the immune response against Herpesvirus (HHV6, EBV, CMV) reactivation. It is induced by some drugs (allopurinol, anticonvulsants, sulfasalazine, minocycine...). Its early diagnosis is necessary for a rapid discontinuation of the culprit drug. Its management includes a long-term followup, and according to the severity either topical steroids, systemic steroids, intravenous gammaglobulins, or antiviral.