Drug reaction with eosinophilia and systemic symptoms: A drug-induced hypersensitivity syndrome with variable clinical features

Drug reaction with eosinophilia and systemic symptoms (DRESS) or drug-induced hypersensitivity syndrome (DIHS) involves a unique and severe adverse drug reaction. Patients present with fever, rash, lymphadenopathy, hematological abnormalities, systemic illness, and may suffer from prolonged courses. Although the precise pathogenesis of DRESS/DIHS is not fully understood, it is widely considered to be an immunological reaction to a drug or drug metabolites. In this review article, we discuss the historical aspects of nosology, variable clinical and histopathological features, advantages and disadvantages of using an international Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) and Japanese DIHS criteria, pathogenesis, treatment, and long-term sequelae of DRESS/DIHS. Early recognition of this syndrome, withdrawal of suspected culprit drugs, and adequate supportive care are mainstays of improving patient prognosis and reducing morbidities and mortality. Moreover, some DRESS/DIHS patients may develop long-term sequelae, especially autoimmune diseases and end organ failure. Physicians should be aware of these possibilities in patients after DRESS/DIHS and cautiously follow-up symptoms and laboratory tests for early detection of these sequelae