SCIT vs SLIT for Allergic Rhinitis: Efficacy Outcomes Compared

Both treatment options were found to be effective for adults with allergic rhinitis or rhinoconjunctivitis.

Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) were found to be equally effective in treating adult patients with allergic rhinitis or rhinoconjunctivitis (AR/C), according to the findings of a systematic review and meta-analysis published in The Laryngoscope.

To compare the effectiveness of SCIT and SLIT in improving outcomes and quality of life in adult patients with AR/C, the study authors searched PubMed, Cochrane Library, EMBASE, and Web of Science for relevant studies published between inception to July 30, 2020. Potentially relevant studies were screened and the risk of bias was assessed by 2 independent reviewers. Outcome measures included symptom scores (SS; a measure of nasal, ocular, lung, and other allergic symptoms using a severity scale), medication scores (MS; based on frequency of medication use), combined symptom and medication scores (CSMS), and quality of life assessment using the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ).

“Seven SCIT vs SLIT randomized controlled trials (RCTs) demonstrated no significant differences for any outcomes, but insufficient data precluded direct meta‐analysis,” the study authors reported. For the adjusted indirect comparisons, a total of 46 RCTs from 39 studies were included; 13 RCTs assessed SCIT vs placebo and 33 RCTs assessed SLIT vs placebo.

Findings of the indirect comparison revealed that, compared with placebo, SCIT significantly improved SS (standardized mean difference [SMD], 0.40; 95% CI, 0.31-0.49), MS (SMD, 0.26; 95% CI, 0.14-0.39), CSMS (SMD, 0.42; 95% CI, 0.17-0.67), and RQLQ (MD, 0.24; 95% CI, 0.04-0.44).

Results also favored SLIT over placebo for SS (SMD, 0.42; 95% CI, 0.32-0.53), MS (SMD, 0.40; 95% CI, 0.28-0.53), CSMS (SMD, 0.37; 95% CI, 0.29-0.45), and RQLQ (MD, 0.32; 95% CI, 0.20-0.43).

Additionally, no statistically significant differences were observed for any outcome measure when pooled SCIT vs placebo data were compared with pooled SLIT vs placebo data.

“Based on results from an adjusted indirect comparison, treatment with either SCIT or SLIT results in comparable patient outcomes, so the decision for choosing between the 2 may be guided by other considerations, such as availability, cost, and patient preference,” the authors concluded.


Tie K, Miller C, Zanation AM, Ebert Jr CS. Subcutaneous versus sublingual immunotherapy for adults with allergic rhinitis: A systematic review with meta-analyses. [published online April 30, 2021.] Laryngoscope. doi: 10.1002/lary.29586