Relationship of airway sensory hyperreactivity to asthma and psychiatric morbidity

Patients with airway symptoms induced by chemicals and odors are common in allergy clinics, but the problems cannot be explained by allergic or asthmatic reactions. Previous studies have shown that these patients often have increased sensitivity to inhaled capsaicin, which is known to reflect sensory reactivity; a diagnosis of airway sensory hyperreactivity (SHR) has been suggested for this condition.

To examine the relationship between asthma and SHR and to investigate whether patients with SHR show signs of increased psychiatric morbidity.

This study included 724 patients who were attending an allergy center because of suspected allergy or asthma. All the patients completed a quantitative questionnaire on self-reported affective reactions and behavioral disruptions caused by odorous/pungent substances. A standardized capsaicin inhalation test was performed and a questionnaire to assess psychiatric morbidity was administered in patients with pronounced chemical sensitivity to identify those with SHR.

The prevalence of SHR was approximately 6% in asthmatic patients in the allergy center population, which is in accordance with the prevalence in a general population. There was no significant indication that SHR was related to either depression or anxiety.

There is no strong relationship between SHR and either asthma or psychiatric morbidity.