Fig. 1From: Practical guide for evaluation and management of beta-lactam allergy: position statement from the Canadian Society of Allergy and Clinical ImmunologyPenicillin allergy risk stratification, and contraindications to re-administration. 1. Immediate reaction (type I or IgE-mediated): symptoms within 2 h after taking the first dose, and duration of symptoms < 24 h. 2. Delayed reaction (types II, III and IV): symptoms > 2 h after drug administrationBack to article page