Background Asthma and allergic rhinitis are the two most common chronic disorders in childhood and adolescence. To date, no study has examined the impact of comorbid allergic rhinitis on asthma control in children.

Objective To examine the prevalence of allergic rhinitis in children with asthma, and the impact of the disease and its treatment on asthma control.

Methods A cross-sectional survey in 203 children with asthma (5–18 years) using validated questionnaires on rhinitis symptoms (stuffy or runny nose outside a cold) and its treatment, and the paediatric Asthma Control Questionnaire (ACQ). Fraction of nitric oxide in exhaled air (FeNO) was measured with a Niox Mino analyser; total and specific IgE levels were assessed by the Immunocap system.

Results 157 children (76.2%) had symptoms of allergic rhinitis but only 88 of these (56.1%) had been diagnosed with the condition by a physician. ACQ scores were worse in children with allergic rhinitis than in those without the condition (p=0.012). An ACQ score ≥1.0 (incomplete asthma control) was significantly more likely in children with allergic rhinitis than in those without (OR 2.74, 95% CI 1.28 to 5.91, p=0.0081), also after adjustment for FeNO levels and total serum IgE. After adjustment for nasal corticosteroid therapy, allergic rhinitis was no longer associated with incomplete asthma control (OR 0.72, 95% CI 0.47 to 1.12, p=0.150).

Conclusion Allergic rhinitis is common in children with asthma, and has a major impact on asthma control. The authors hypothesise that recognition and treatment of this condition with nasal corticosteroids may improve asthma control in children, but randomised clinical trials are needed to test this hypothesis.