DRESS Syndrome: Recognition and Management

Overview / Definition DRESS syndrome is a potentially life-threatening drug-induced hypersensitivity reaction that typically occurs 2-8 weeks after exposure to a causative agent. The acronym DRESS stands for Drug Reaction with Eosinophilia and Systemic Symptoms, reflecting the hallmark features of this condition, which include fever, rash, lymphadenopathy, eosinophilia, and involvement of multiple organ systems. Epidemiology DRESS syndrome is relatively rare, with an estimated incidence of 1 in 1,000 drug exposures. It can occur in patients of any age but is most commonly reported in adults. The syndrome is associated with several classes of medications, particularly: Anticonvulsants (e.g., phenytoin, carbamazepine) Antibiotics (e.g., sulfonamides, minocycline) Allopurinol Certain antipsychotics and NSAIDs Pathophysiology / Mechanism The exact mechanism of DRESS syndrome is not fully understood, but it is thought to involve a complex interplay of genetic predisposition and immune dysregulation. Key features include: Activation of CD4+ T cells and CD8+ T cells leading to cytokine release. Increased production of eosinophils, contributing to tissue inflammation. Possible reactivation of latent viral infections, such as HHV-6 and EBV. Clinical Presentation The clinical presentation of DRESS syndrome typically includes: Fever: Often >38.5°C Rash: Morbilliform or exfoliative, often involving >50% of body surface area Lymphadenopathy: Often generalized Hematologic abnormalities: Eosinophilia (>1500 cells/μL), atypical lymphocytes, and thrombocytopenia Organ involvement: Hepatitis, nephritis, pneumonitis, cardiomyopathy, and/or hematologic manifestations Diagnosis / Workup Diagnosis of DRESS syndrome is primarily clinical, supported by laboratory findings. Key steps include: Detailed medication history to identify potential triggers. Laboratory tests to evaluate eosinophilia and assess organ function (liver enzymes, renal function tests). Consideration of skin biopsy if th