Table 1.

Similarities and differences between Americans and Europeans in the management of β-lactam antibiotic hypersensitivity

	American perspective	European perspective	Comment
General rules	Evaluation mainly by signs and symptoms In history of severe reactionsa: avoidance of allergy tests In history of non-severe reactions: diagnostic approach can be applied	Evaluation by clinical history and allergy tests	Different
DPTs	Recommended if other diagnostic tools are negative Consider contraindications	Recommended if other diagnostic tools are negative Consider contraindications	Similar
Desensitization	Recommended Consider indications and contraindications	Recommended Consider indications and contraindications	Similar
Immediate reactions
General rules	SPTs followed by IDTs are the first to perform Perform DPTs if STs are negative	SPTs followed by IDTs are the first to perform Perform DPTs if STs and in vitro tests are negative	Similar
STs	Penicillins
	Recommended: PPL: 5 × 10−5 mol/L MDM: 2 × 10−2 mol/L BP: 10,000 IU/mL	Recommended PPL: 5 × 10−5 mol/L MDM: 2 × 10−2 mol/L BP: 10,000 IU/mL	Similar
	Semisynthetic penicillins
	Not routinely recommendeda	Recommended AX: 20 mg/mL AMP: 20 mg/mL	Different
	β-Lactamase inhibitors
	Not recommendeda	Recommended with original drug and the individual components of the antibiotic combination	Different
	Cephalosporins
	Not recommendeda	Recommended with original drug (max: 2–20 mg/mL)	Different
	Aztreonam/carbapenems
	Not recommendeda	Recommended Aztreonam: 2 mg/mL; Imipenem/cilastatin: 0.5 mg/mL of each component; Meropenem: 1 mg/mL; Ertapenem: 1 mg/mL	Different
	Commercially available kits
	PRE-PEN® (AllerQuest LLC, Plainville, CT, USA) PPL: 6.0 × 10−5 mol/L	DAP® (Diater, Leganés, Madrid, Spain) BP-OL: 0.04 mg/mL (8.64 × 10−5 mol/L) MD: Benzylpenilloate 0.5 mg/mL (1.5 × 10−3 mol/L) AX: 20 mg/mL	Different
In vitro tests	Serum specific IgE assays
	Not recommended	Testing with penicillins is recommended	Different
	Basophil activation tests
	Not recommended	Recommended as complementary to sIgE	Different
Non-immediate reactions
STs/PTs	Not recommended	PTs followed by delayed-reading IDTs are recommended in routine approach In case of positive PTs, IDTs may be avoided	Different
In vitro tests	Not recommended	Not recommended	Similar
Retest
	Repeating penicillin STs routinely is not indicated in patients with a history of non-severe penicillin reactions who have tolerated 1 or more oral penicillin courses	Weakly recommended: retesting (2–4 weeks later) patients who suffered severe immediate reactions to BLs and display negative results in the first allergy evaluation, including DPTs

DPTs drug provocation tests, STs skin tests, SPTs skin prick tests, IDTs intradermal tests, PTs patch tests, PPL benzylpenicilloyl-poly-l-lysine, POL benzylpenicilloyl-octa-l-lysine, MDM minor determinant mixture, MD minor determinant, BP Benzylpenicillin, AX amoxicillin, AMP ampicillin, sIgE specific IgE

^aDue to unknown negative predictive values of STs