DHS/DRESS is best described as which of the following?

• A. A mild allergic skin reaction with immediate onset
• B. A severe idiosyncratic multi-system reaction with fever, rash, and organ involvement occurring weeks after exposure
• C. A mild gastrointestinal intolerance
• D. An asymptomatic laboratory abnormality

Answer: (B)

DHS/DRESS is a severe, idiosyncratic drug hypersensitivity reaction that typically appears weeks after starting the offending medication. It presents with fever, a widespread rash, facial swelling, and lymphadenopathy, along with eosinophilia and involvement of one or more internal organs, most commonly the liver, but it can affect the kidneys, lungs, heart, and others. The delay in onset (usually about 2–6 weeks) and the multisystem nature are key clues that distinguish this from milder, purely local or immediate-type reactions. The underlying mechanism involves an immune-mediated T-cell response, and reactivation of certain herpesviruses (like HHV-6) has been implicated in some cases. Management centers on stopping the suspected drug promptly and avoiding re-exposure; corticosteroids are often used if there is significant organ involvement, with careful monitoring of liver enzymes, renal function, and other affected systems. Drugs commonly implicated include anticonvulsants (e.g., carbamazepine, phenytoin, lamotrigine), allopurinol, sulfonamides, and certain antibiotics.

This pattern—severe, multi-organ involvement with fever and rash that arises weeks after drug exposure—best describes DHS/DRESS, not milder immediate skin reactions, simple gastrointestinal intolerance, or an asymptomatic laboratory abnormality.