Drug reaction with eosinophilia and systemic symptoms (DRESS/DiHS) has a delayed onset. What is the typical latency period from drug initiation to symptom onset, and which drug is most commonly implicated in India?
- A 2–8 weeks; aromatic anticonvulsants (carbamazepine, phenytoin, phenobarbitone) ✓
- B 2–6 hours; amoxicillin
- C 1–2 days; sulfonamides
- D 3–6 months; allopurinol
Correct answer: A. 2–8 weeks; aromatic anticonvulsants (carbamazepine, phenytoin, phenobarbitone)
Explanation
DRESS has a distinctive delayed onset of 2–8 weeks (range 2–12 weeks) after initiating the causative drug — a key feature distinguishing it from IgE-mediated anaphylaxis (minutes to hours) and SJS (days to weeks). Aromatic anticonvulsants (carbamazepine, phenytoin, phenobarbitone, lamotrigine) are the most common culprits in India; allopurinol and dapsone are also significant. The prolonged latency is attributed to reactivation of latent HHV-6 (and sometimes HHV-7, EBV, CMV) as part of pathogenesis.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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