Adding intranasal antihistamines to inhaled steroids for the management of patients with allergic rhinitis requires further study
The benefit of adding an intranasal antihistamine to mono-therapy with an inhaled steroid is still uncertain and requires further study. This was the conclusion of a systematic review and meta-analysis by a South Korean group.
Allergic rhinitis (AR) is a heterogeneous disorder that is characterised by one or more symptoms including sneezing, itching, nasal congestion, and rhinorrhoea. The disorder is common, affecting 10 to 30 percent of children and adults in the United States and other industrialised countries and can can be either seasonal (SAR) or perennial (PAR).
In a 2020 guideline on the management of AR, it was recommended that in patients with SAR, either a combination of an intranasal corticosteroid (INCS) and an intranasal antihistamine (INAH) or an INCS alone would be an appropriate choice. Moreover, the authors added that since the combination of an INCS and an INAH might act faster than an INCS alone, this could represent a preferred option for patients. In addition, the guidelines do in fact, recommend that for those with moderate-to-severe symptoms, clinicians should use the combination. Although a 2019 systemic review supported both the efficacy and superiority of a combination of the intranasal antihistamine, azelastine and fluticasone in reducing patient-reported symptom scores in allergic rhinitis, it did not include any other intranasal antihistamines.
As a result, for the present systematic review the Korean team searched on PubMed, EMBASE and the Cochrane Central Register of Controlled trials, for studies that included other types of INAH used in combination with nasal corticosteroids and considered both randomised and non-randomised trials. Furthermore, as part of their assessment, the team also examined trials that included data on the adverse events of both treatments.
Intranasal antihistamines and treatment outcomes
The search identified a total of 13 randomised, controlled trials, 10 of which reported differences in symptom scores and 12 that described adverse events. Two other intranasal antihistamines identified and included in the analysis were bepotastine and olopatadine.
When compared to mono-therapy with an INCS, the combination of an INCS/INAH, reduced the mean morning and evening 12-hour total nasal symptom score (TNSS) more significantly (mean difference, MD = -0.44, 95% CI -0.61 TO -0.27, p < 0.00001) than INCS treatment alone. In addition, the combination also significantly reduced the total ocular symptom score (MD = -0.62, 95% CI -1.05 to -0.19, p = 0.005).
In addition, compared to INCS mono-therapy, combination with an INAH also significantly improved the total mean rhinoconjuctivitis quality of life score (MD = -0.24, 95% CI -0.42 to -.06, p = 0.009).
However, despite the enhanced therapeutic benefit derived from the combination, it was also associated with a significantly greater risk of treatment-emergent adverse effects compared to INCS mono-therapy such as dysgeusia, i.e., a bad/bitter taste in the mouth or throat (relative risk, RR = 1.52, 95% CI 1.28 – 1.81, p < 0.00001).
The authors found that while the combination of an INCS/INAH was significantly better at alleviating nasal and ocular symptoms, as well as improving quality of life compared to INCS mono-therapy, use of the combination did not reach the minimal clinically important difference for either total nasal symptoms or rhinoconjuctivitis quality of life score.
Based on their findings, the authors concluded that further studies are needed to verify the potential utility of the INCS/INAH combination compared to INCS mono-therapy.
Kim M et al. Intranasal antihistamine and corticosteroid to treat in allergic rhinitis: A systematic review and meta‐analysis Allergy 2022