European Survey on Adverse Systemic Reactions in Allergen Immunotherapy (EASSI): a real-life clinical assessment.

Background: Outside clinical trials, data on systemic reactions (SRs) due to allergen immunotherapy (AIT) are scarce.

Methods: A prospective, longitudinal, web-based survey of 'real-life' respiratory allergen immunotherapy (AIT) clinical practice was conducted in France, Germany and Spain. SRs were recorded and coded according to the Medical Dictionary for Regulatory Activities (MedDRA) and risk factors associated with SRs were identified.