Effectiveness of Subcutaneous Versus Sublingual Immunotherapy for the Treatment of Allergic Rhinoconjunctivitis and Asthma: A Systematic Review

Allergen-specific immunotherapy is widely used in the management of patients with allergic rhinoconjunctivitis and asthma, but the best route of delivery is unclear.We performed a systematic review of studies with head-to-head comparison of effectiveness and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) in the treatment of allergic rhinoconjunctivitis and asthma.MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were searched through December 21, 2012. We included English language randomized controlled trials that enrolled patients with allergic rhinoconjunctivitis and/or asthma with head-to-head comparisons of SCIT with SLIT. Paired reviewers extracted detailed information from included articles on standardized forms and assessed the risk of bias in each article.Eight trials compared the effectiveness and safety of SCIT and SLIT. The effectiveness of the 2 forms of immunotherapy in managing allergic asthma and rhinoconjunctivitis were reported in 4 and 6 clinical trials, respectively. Low-grade evidence supports greater effectiveness of SCIT than SLIT for asthma symptom reduction and also at reducing a combined measure of rhinitis symptoms and medication use. Moderate-grade evidence supports greater effectiveness of SCIT than SLIT for nasal and/or eye symptom reduction. All 8 trials reported on adverse events with an episode of anaphylaxis reported in a child treated with SCIT.Our review provides low-grade evidence to support that SCIT is superior to SLIT for reduction in asthma symptoms and moderate-grade evidence for reduction of allergic rhinoconjunctivitis. Additional studies are required to strengthen this evidence base for clinical decision making.