Evaluation of drug provocation tests without prior skin testing in children with suspected penicillin allergy and correlation with PEN-FAST: A single-center study.

Purpose: To evaluate patients with suspected penicillin allergy in whom skin testing was omitted during immediate and delayed reactions before drug provocation test (DPT).

Methods: This retrospective study analyzed patients aged 0-18 years with suspected penicillin allergy between 2020 and 2023. Data on hypersensitivity reaction history, laboratory tests, PEN-FAST scores, and DPT records were collected.

Results: We evaluated 75 patients (male: 61.3%; median age at index reaction: 4 [range: 1-15] years) with suspected penicillin allergy. Nearly all reactions occurred at home (98.7%) following oral administration, with antihistamines being the most common treatment (56%). Urticaria was the most frequent manifestation in immediate reactions (30.7%), whereas maculopapular exanthema was predominant in delayed reactions (33.7%). Amoxicillin-clavulanic acid was the most frequently implicated drug (85.3%). The median PEN-FAST score was 3 (range: 0-5). Immediate reactions were significantly more common in females (p < 0.05). In total, 78 DPTs were performed, and four patients tested positive, all experiencing mild cutaneous reactions. No life-threatening reactions were observed. At the 3-month follow-up, 90.7% of patients tolerated beta-lactam antibiotics, though 4% chose to avoid them despite negative DPT results.

Conclusion: In our study, we successfully performed DPT without major complications by omitting skin testing in both immediate and delayed reactions. Our findings suggest that in delayed reactions, direct DPT can safely replace skin testing. Notably, we also propose that after in vitro tests, DPT may be safely used in immediate reactions without additional in vivo testing. Also, this is the first study to evaluate PEN-FAST in children with suspected penicillin allergy in our country, offering practical value for clinicians and patients.

What is known: • The label of drug allergy in children is assigned far more frequently than the actual diagnosis of true allergic reactions. • Due to unverified drug allergy diagnoses, patients face challenges such as inadequate treatment and the development of antibiotic resistance.

What is new: • In cases with immediate reactions, including anaphylaxis, direct drug provocation test (DPT) performed without prior skin testing can be conducted without severe reactions. • The PEN-FAST score has been observed to be highly effective in ruling out beta-lactam allergy in pediatric patients with low scores.