Sinusitis and asthma: associated airway diseases.

Sinusitis and asthma often coexist in patients. In fact, these airways disorders are similar histologically, with tissue eosinophils, increased glandular tissue, and edema. Medical or surgical therapy for sinusitis often greatly improves asthma, suggesting that sinusitis may exacerbate asthma. Possible mechanisms by which asthma could be worsened by sinus disease include neural reflex pathways and interference with the important nasal functions of heating, humidification, and filtration. Health professionals treating asthmatic patients should consider sinusitis as a possible underlying cause, in addition to other triggers (e.g., allergic rhinitis and gastroesophageal reflux disease).