Systemic reactions with aeroallergen cluster immunotherapy in a clinical practice.

BACKGROUND

Subcutaneous allergen-specific immunotherapy is a proven, highly effective treatment for immunoglobulin E-mediated diseases. Despite its proven benefits, only a small percentage of patients with allergic disease use immunotherapy, in part because of the inconvenience associated with treatment. Cluster allergen immunotherapy may offer patients a more convenient treatment option but is prescribed infrequently because of the perception that accelerated immunotherapy buildup leads a higher rate of systemic reactions.

OBJECTIVE

To examine the safety of cluster immunotherapy and identify risk factors for systemic reactions during cluster buildup.

METHODS

A retrospective, observational review in a large, multicenter allergy practice group was conducted for patients receiving cluster immunotherapy between May 2008 and October 2010.

RESULTS

Data from 441 patients receiving cluster immunotherapy were collected. Forty-eight patients (10.9%) experienced systemic reactions. Based on the World Allergy Organization Subcutaneous Immunotherapy Systemic Reaction Grading System, 18 grade 1 reactions (38.3%), 23 grade 2 reactions (48.9%), 5 grade 3 reactions (10.6%), 1 grade 4 reaction (2.1%), and no grade 5 reactions were seen. Risk factors for a systemic reaction included: female sex, physician diagnosis of asthma, age 21 to 40 years, and inclusion of certain allergens in the immunotherapy vaccine.

CONCLUSIONS

Cluster immunotherapy allows patients to reach their immunotherapy maintenance dose more rapidly and may lead to more rapid symptomatic improvement. However, the cluster buildup may lead to a higher rate of systemic reactions. Identifying risk factors for systemic reactions will help improve the safety of cluster immunotherapy.