BACKGROUND Drug hypersensitivity reaction (DHR) poses significant challenges in clinical practice, with some patients experiencing more severe reactions upon re-exposure. Understanding the factors contributing to escalation into more severe reactions is crucial for improving patient safety. This study aimed to investigate the clinical characteristics and risk factors associated with the progression from non-severe DHR to anaphylaxis.

METHODS A multicenter retrospective study was conducted using data from a drug-induced anaphylaxis registry across 10 university hospitals in Korea. Clinical data, including information on culprit drugs, DHR history, and the severity of reactions, were assessed.

RESULTS Among 494 cases of drug-induced anaphylaxis, 417 cases (84.4%) occurred without prior DHR, while 77 cases (15.6%) had a history of non-severe DHR. Of these, 43 cases had a previous DHR to a drug of the same class, and 34 cases involved DHR to drugs of different classes. In the group with prior DHR to a drug of the same class, anaphylaxis occurring in daily life was significantly more common compared to those reacting to a different class of drug or those with no prior DHR (48.8% vs. 23.5% or 22.5%, p = 0.008 and < 0.001, respectively). Non-steroidal anti-inflammatory drugs (NSAIDs), H2 blockers, and penicillins were identified as risk factors for anaphylaxis evolving from non-severe DHR.

CONCLUSION Enhanced vigilance is required for patients with a history of non-severe DHR to NSAIDs, H2 blockers, and penicillins as re-exposure may lead to the progress to anaphylaxis.