Airway hyperresponsiveness in allergic rhinitis. A risk factor for asthma

Area of Science:

• Pulmonology
• Allergy and Immunology

Background:

• Allergic rhinitis is a common condition.
• Asthma is a chronic respiratory disease.
• Predicting asthma development in allergic rhinitis patients is clinically important.

Purpose of the Study:

• To determine if methacholine inhalation challenge can predict asthma development in patients with allergic rhinitis.
• To assess the long-term risk of asthma in allergic rhinitis patients based on bronchial responsiveness.

Main Methods:

• Prospective study of ragweed-sensitive patients over 4-5 years.
• Methacholine inhalation challenge performed at baseline and follow-up.
• Assessment of bronchial hyperresponsiveness using methacholine.

Main Results:

• 16 of 40 patients (40%) showed methacholine hyperresponsiveness initially.
• Three of these 16 patients (19%) developed asthma within 1.5-5 years.
• No patients with normal baseline methacholine response developed asthma.
• Degree of hyperresponsiveness (PD20) did not predict which responders would develop asthma.

Conclusions:

• Allergic rhinitis patients with methacholine hyperresponsiveness are at significantly greater risk of developing asthma.
• Normal bronchial challenge responses in allergic rhinitis patients indicate a low risk for asthma development.