A RECENT study conducted in European adults has provided robust evidence that a direct single-dose drug provocation test (DPT), without prior skin testing (ST), is both safe and effective for excluding penicillin (PEN) allergy in patients assessed as low risk. This approach successfully delabelled 94% of participants who had previously been labelled as allergic to beta-lactam (BL) antibiotics, a group that includes PEN and is widely used as first-line treatment for bacterial infections.
A label of BL allergy often leads to the use of second-line antibiotics, which are less effective, more toxic, and more costly. Furthermore, such mislabelling increases hospital stays, mortality risk, and antibiotic resistance – a major public health threat in the EU and globally. However, it is estimated that 70–90% of people labelled as allergic to BLs are not truly allergic.
This study is especially important because existing diagnostic methods, including ST, have shown limited sensitivity and are time-consuming, costly, and not risk-free. Moreover, previous research on this topic has mostly focused on paediatric or non-European populations, limiting its relevance to the adult European context.
Participants in the study underwent a single-dose DPT without ST, and the results confirmed that even those with previously ambiguous or mild delayed cutaneous reactions – and some classified as intermediate risk – could safely undergo this simplified approach. Importantly, none of the patients with an unknown index PEN or past intramuscular administration reacted, supporting the theory that some allergies are mislabelled due to historical medical practices.
Additionally, in vitro testing using lymphocyte transformation tests (LTT) helped confirm a T-cell mediated mechanism in true allergic reactions, with high sensitivity and specificity.
In summary, this study supports integrating direct single-dose DPT into routine clinical practice for low-risk PEN allergy patients in Europe, offering a fast, reliable, and safe method to reduce unnecessary allergy labels and promote better antibiotic stewardship.
Reference
Labella M et al. Direct single-dose drug-provocation test is safe for delabelling penicillin low-risk reactions in adults. Allergy. 2025;DOI:10.1111/all.16567.
