Published Online: June 6, 2013
Allergic asthma and rhinitis are common and disruptive clinical problems. Allergen immunotherapy is typically recommended when allergic symptoms are not controlled by environmental control and medications. Even though the Food and Drug Administration (FDA) has approved the use of only subcutaneous immunotherapy injections (SCIT) for treatment of allergic rhinitis and asthma, some physicians are using sublingual immunotherapy oral drops (SLIT) off-label in the United States. With the increasing evidence of the effectiveness of both SCIT and SLIT, physicians and patients are faced with an increasing number of potential immunotherapy options from which to choose.
Recently, in The Journal of Allergy and Clinical Immunology: In Practice, Chelladurai et al. reported the findings of a systematic review evaluating the effectiveness of SCIT versus SLIT. They included randomized controlled trials that directly compared the two forms of immunotherapies within the same study. Effect of these therapies on allergic symptoms and medication use were the primary outcomes evaluated.
This qualitative systematic review demonstrated greater reduction in symptoms of allergic rhinoconjunctivitis and allergic asthma with SCIT compared to SLIT. There was little difference between the two forms of immunotherapies in reducing medication use. Much of this evidence was derived from dust mite allergen studies.
This review is limited by the many differences in data collection and scoring in the original articles, which made it impossible to pool the data quantitatively, as well as the lack of high quality studies. In light of these limitations, the evidence, even though from head-to-head comparisons of the two interventions, is of low to moderate grade. This means that if newer, high quality studies are performed, this may change the conclusions of the authors. While both forms of immunotherapy have been shown as effective treatment options, the evidence base needs to be strengthened by high quality studies in the future that make a fair comparison of the two immunotherapies.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.