Patients on subcutaneous allergen immunotherapy are at risk of intramuscular injections

BackgroundAllergen-specific subcutaneous immunotherapy is an effective treatment for certain allergic disorders. Ideally, it should be administered into the subcutaneous space in the mid-posterolateral upper arm. Injections are commonly given using a standard allergy syringe with a needle length of 13 mm. Therefore, there is a risk of intramuscular administration if patients have a skin-to-muscle depth <13 mm, which may increase the risk of anaphylaxis. The objective of this study was to determine whether the needle length of a standard allergy syringe is appropriate for patients receiving subcutaneous immunotherapy.MethodsUltrasounds of the left posterolateral arm were performed to measure skin-to-muscle depth in 200 adults receiving subcutaneous immunotherapy. The proportion of patients with a skin-to-muscle depth >13 mm vs. ≤13 mm was assessed and baseline …