Efficacy of dual sublingual immunotherapy with Japanese cedar pollen and house dust mite allergens in patients with allergic rhinitis sensitized to multiple allergens

OBJECTIVE: In the present study, we examined the effects of dual sublingual immunotherapy (SLIT) with Japanese cedar pollen (JCP) and house dust mite (HDM) allergens on nasal symptoms during the peak pollen period (PPP) and in late fall (LF) in patients with allergic rhinitis (AR) sensitized to both JCP and HDM. We then compared the efficacy of dual‐SLIT with JCP and HDM to that of mono‐SLIT with JCP at PPP. METHODS: Twenty‐five bisensitized patients with AR who showed positive serum specific immunoglobulin E (IgE) against both JCP and HDM were enrolled. In dual‐SLIT, 16 patients received JCP drops/tablets and HDM tablets concurrently. In mono‐SLIT with JCP, nine patients received JCP drops/tablets. Nasal symptoms were scored on a 0–4 point scale. RESULTS: The nasal scores at PPP and in LF in the bisensitized patients with AR who received dual‐SLIT with JCP and HDM in 2019 were significantly lower than those in the same patients who received antihistamines only in 2018. The decrease in scores of nasal obstruction at PPP from 2018 to 2019 in patients who received dual‐SLIT was significantly greater than those in patients who received mono‐SLIT with JCP. Dual‐SLIT was well tolerated and only had mild adverse effects. CONCLUSION: These findings suggest that dual‐SLIT suppressed both JCP‐induced seasonal and HDM‐induced perennial nasal symptoms in bisensitized patients with AR. Dual‐SLIT was more effective in suppressing nasal obstruction at PPP than mono‐SLIT with JCP with limitation of baseline characteristics not to be controlled between the two groups, suggesting that dual‐SLIT suppressed HDM‐induced priming effects, thus resulting in further suppression of nasal obstruction at PPP. LEVEL OF EVIDENCE: 3b, a case‐controlled study