Comparison of allergen immunotherapy practice patterns in the United States and Europe

To discuss important differences and similarities in the allergen specific immunotherapy (SIT) treatment practices for aeroallergen sensitivity in the United States and Europe.

Information on regulation and standardization in the United States and Europe was obtained from a Food and Drug Administration Allergenic Products Advisory Committee meeting, published literature, personal communications, and information obtained from the extract manufacturers.

Information from the published literature included articles known to the authors and acknowledged consultants, textbooks, and PubMed, with search terms dependent on the particular subtopic.

Key differences between Europe and the United States include allergen extract regulation, standardization, formulation, types of allergen extracts, routes of administration, and reimbursement. Most SIT is formulated in US allergists' offices, whereas virtually all SIT is formulated by extract manufacturers in Europe. Sublingual immunotherapy represents a significant percentage of SIT treatment in Europe (approximately 45%), but only a small percentage of US allergists (approximately 5.9%) prescribe sublingual immunotherapy. Similarities between European and US allergist specialists lie in their perception of SIT and approach to providing optimal SIT care, which is detailed in their practice guidelines.

Significant differences and similarities exist in SIT practice patterns of US and European allergy specialists. The differences lie primarily in the availability of allergen extracts and how these extracts are formulated. A key similarity is that both recognize the need for ongoing research focused on developing safer and more effective SIT.