How safe and effective is subcutaneous immunotherapy (SCIT), particularly single allergen regimens, for treating allergic rhinoconjunctivitis and asthma?
Background: Allergen immunotherapy is usually recommended for patients whose allergic rhinoconjunctivitis and asthma symptoms cannot be controlled by environmental and pharmaceutical means or who do not adhere to medication regimens. SCIT suppresses or eliminates symptoms by administering increasing doses of an allergen-containing extract. This study focuses on SCIT formulations that are available in the United States.
Explore this issue:March 2014
Study design: Database review of studies published between 1967 and May 2012.
Setting: MEDLINE, Embase, LILACS, Cochrane Central Register of Controlled Trials, public registries of clinical trials, and scientific information packets requested from relevant pharmaceutical companies.
Synopsis: Sixty-one studies (40 single allergen, 21 multiple allergen) with 3,577 participants met the inclusion criteria. High-strength evidence of effectiveness was found for SCIT reducing asthma medication use and improving symptom scores, rhinitis/rhinoconjunctivitis symptoms, allergic conjunctivitis symptoms, combined (nasal, ocular, and bronchial) symptoms scores, and disease-specific quality of life. Moderate-strength evidence of effectiveness was found for SCIT improving combined asthma and rhinoconjunctivitis symptom scores; and reducing asthma and rhinoconjunctivitis medication use, rhinitis/rhinoconjunctivitis medication use, and combined rhinitis/rhinoconjunctivitis plus asthma medication use. Low-strength evidence of effectiveness was found for SCIT improving asthma symptom–medication scores and rhinitis/rhinoconjunctivitis symptom–medication scores. Findings were variable and/or inconsistent for pulmonary function testing and bronchial reactivity. In terms of safety, local reactions were common; the most common systemic reactions were respiratory. General symptoms, such as headache, fatigue, and arthritis, and unspecified reactions also occurred frequently. The majority of overall reactions were of mild or unspecified severity, and no deaths were reported. Limitations included substantial study heterogeneity, extreme variability in primary outcomes scoring, allergen dosing, treatment schedules, and safety data reporting methods.
Bottom line: Moderate to strong evidence supports SCIT effectiveness for the treatment of allergic rhinitis and asthma, particularly with single-allergen immunotherapy regimens.
Citation: Erekosima N, Suarez-Cuervo C, Ramanathan M, et al. Effectiveness of subcutaneous immunotherapy for allergic rhinoconjunctivitis and asthma: a systematic review. Laryngoscope. 2014;124:616-627.