Evidence-based dosing of maintenance subcutaneous immunotherapy: a contemporary review of state-of-the-art practice

Background: Subcutaneous immunotherapy is an effective allergy treatment only if properly dosed. In this article we review the data on the probable effective dose range for subcutaneous immunotherapy and convert the recommended doses into a clinically relevant format. Methods: A comprehensive literature search of dose-response subcutaneous immunotherapy studies was done of EBM databases, Medline database, PreMedline, and the National Guideline Clearinghouse for the period 1980–2016. Recommended doses were converted to the volume of allergen extract that should be added to a 5-mL maintenance vial. Results: A safe and effective dose for subcutaneous immunotherapy is likely 5–20 μg of major allergen per injection. A 0.5-mL injection from a 5-mL maintenance vial containing 0.2 mL of manufacturer's extract of each allergen should reach the lower end of the probable effective dose range for most allergens. A larger volume of extract is required to reach that range when treatment includes cat, dog, or only 1 dust mite. Increasing beyond the commonly prescribed 0.2 mL of manufacturer's extract added to a 5-mL treatment vial is reasonable for nearly all allergens to achieve a maintenance dose higher in the probable effective dose range. Conclusion: Current otolaryngic allergy practice usually escalates patients to 0.5-mL injections from 5-mL maintenance vials containing 0.2 mL of manufacturer's extract of each allergen. With the main exceptions of cat and dog, those injections administered 1 or 2 times per month likely provide an efficacious dose of allergen and are consistent with published guidelines. A larger volume of extract should be considered in certain clinical situations.