Patients on subcutaneous allergen immunotherapy are at risk of intramuscular injections

Research

Laura Kim, Immaculate Nevis, Ryan Potts, Clark Eeuwes, Arunmozhi Dominic and Harold L Kim

Author Affiliations

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Allergy, Asthma & Clinical Immunology 2014, 10:22  doi:10.1186/1710-1492-10-22

Published: 7 May 2014

Abstract (provisional)

Background

Allergen-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.

Methods

Ultrasounds 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 characteristics of the two groups were compared. The proportion of patients with skin-to-muscle depths + 4 mm, 6 mm, 8 mm and 10 mm were also calculated. Multivariable logistic regression was performed to identify predictors of skin-to-muscle depth.

Results

Of the 200 patients included in the study, 80% had a skin-to-muscle depth - =13 mm; the majority (91%) had a skin-to-muscle depth +4 mm. Body mass index was found to be a significant predictor of skin-to-muscle-depth.

Conclusions

Most patients receiving subcutaneous immunotherapy have a skin-to-muscle depth less than the needle length of a standard allergy syringe (13 mm). These patients are at risk of receiving injections intramuscularly, which may increase the risk of anaphylaxis. Using a syringe with a needle length of 4 mm given at a 45[degree sign] angle to the skin may decrease this risk.

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