Background
Perennial allergic rhinitis (PAR) often coexists in asthmatic patients. Intranasal cellulose powder (ICP) was reportedly effective in ameliorating PAR.

Objective
We investigated whether ICP is equally effective compared with intranasal corticosteroids in improving asthma control as well as nasal symptoms among children with PAR and allergic asthma (AA).

Methods
Between July 2015 and September 2016, we did a single-center, randomized, placebo-controlled trial. Asthmatic children aged 6 to 11 years with mild-to-moderate PAR were randomly assigned to formoterol/budesonide inhalation (4·5 µg/80 µg, twice daily) plus intranasal budesonide 64 µg twice daily (group A), ICP 250 µg thrice daily (group B), or intranasal placebo 250 µg thrice daily (group C) for 8 weeks. The primary outcome was change in asthma control test for children (C-ACT) score from baseline to week 8 posttreatment. Changes in spirometry, peak expiratory flow (PEF), fractional exhaled nitric oxide (FeNO), and visual analog scale (VAS) for nasal and ocular symptoms were detected as secondary outcomes.

Results
We included 121 patients (38 in group A, 41 in group B, and 42 in group C) in full-analysis set. C-ACT score was markedly higher at week 8 compared with baseline (mean difference: 5.11, 6.05, and 4.85 points in groups A, B, and C, respectively; P < .05). There were interactions between baseline and treatment in C-ACT scores (P < .05). Group B demonstrated greater improvement in C-ACT score than group C among children with baseline C-ACT score of 6 to 18. 95% confidence intervals of group A at baseline overlapped with those of groups B and C. The treatment achieved reduced VAS symptoms in groups A and B but not in group C. Incidence of adverse events was comparable. No serious adverse event was reported.

Conclusions
ICP could be recommended for children with PAR and AA who have poorer asthma control.