Immediate allergic reactions to β-lactams: diagnostic accuracy of skin tests

Performance in real life of the European Network on Drug Allergy algorithm in immediate reactions to beta-lactam antibiotics

European Network on Drug Allergy (ENDA) has proposed an algorithm for diagnosing immediate beta-lactam (BL) allergy. We evaluated its performance in real life. During 1994-2014, 1779 patients with suspected immediate reactions to BL were evaluated following ENDA's short diagnostic algorithm. Five hundred and nine patients (28.6%) were diagnosed of BL hypersensitivity. Of them, 457 (25.7%) were at first evaluation [403 by skin tests (ST), 12 by positive IgE and 42 by controlled provocation tests (CPT)]. At second evaluation (SE), 52 additional patients (10.2% of allergic patients) were diagnosed, [50 (2.8%) by ST and 2 (0.1%) by CPT]. Time between reaction and study was significantly longer in patients diagnosed at SE (median 5 vs 42 months; IQR 34 vs 170; P < 0.0001). Anaphylaxis was significantly associated with a diagnosis at SE. European Network on Drug Allergy/EAACI protocol was appropriate and safe when evaluating BL immediate reactions. Re-evaluation should be performed, particularly when anaphylaxis and long interval to diagnosis are present.