What is the cause of persistent coughing after resolution of sinusitis?

From the Guidelines

It's common for a cough to persist after sinusitis has resolved, and this lingering cough, often called post-infectious cough, can last 3-8 weeks after the initial infection clears. To manage this symptom, try over-the-counter options like dextromethorphan (Robitussin DM, 10-20mg every 4 hours) for cough suppression or guaifenesin (Mucinex, 600-1200mg twice daily) to thin mucus, as suggested by 1. Staying hydrated with 8-10 glasses of water daily helps loosen secretions. A saline nasal rinse once or twice daily can reduce post-nasal drip that triggers coughing. Using a humidifier at night and avoiding irritants like smoke or strong fragrances may also help. Honey (1-2 teaspoons) can soothe throat irritation from coughing.

Key Considerations

• In patients with postinfectious cough, when the cough adversely affects the patient’s quality of life and when cough persists despite use of inhaled ipratropium, consider the use of inhaled corticosteroids, as recommended by 1.
• For severe paroxysms of postinfectious cough, consider prescribing 30 to 40 mg of prednisone per day for a short, finite period of time when other common causes of cough have been ruled out, as suggested by 1.
• Central acting antitussive agents such as codeine and dextromethorphan should be considered when other measures fail, according to 1.

Management

• Try over-the-counter options like dextromethorphan or guaifenesin to manage symptoms, as these are commonly recommended for post-infectious cough, as seen in 1.
• Consider a trial of inhaled ipratropium as it may attenuate the cough, as suggested by 1.
• If your cough lasts more than 8 weeks, worsens significantly, or is accompanied by fever, shortness of breath, or discolored phlegm, consult a healthcare provider as this could indicate a secondary infection or different condition, as advised by 1.

From the Research

Sinusitis and Coughing

• Sinusitis is often associated with coughing, but in some cases, the coughing may persist even after the sinusitis has resolved.
• According to a study published in 2007 2, patients with postnasal drip (PND) without objective evidence of sinonasal inflammatory disease were treated with proton pump inhibitors (PPIs) and showed significant reduction in PND frequency, hoarseness, and chronic cough.

Causes of Persistent Coughing

• Upper airway cough syndrome (UACS) is one of the most common causes of chronic cough, and it can be present with or without associated rhinitis and chronic rhinosinusitis 3.
• Postnasal drip (PND) is a common complaint in primary care and ear-nose-throat offices, and it is often associated with chronic cough, but the traditional pathophysiology of PND related to sinonasal disease does not clearly lead to chronic cough 4.
• It is postulated that PND stems from dysfunction of normal mucus clearance mechanisms, but there is no definitive evidence elucidating an exact pathophysiology 5.

Treatment of Persistent Coughing

• Treatment of UACS includes dual therapy with H1 receptor antihistamines and decongestants, and diagnosis is confirmed when therapeutic intervention results in symptom resolution 3.
• The effect of PPI therapy on laryngeal findings is mixed, and patients may experience symptomatic improvement before changes in laryngoscopic appearance 2.
• There is a lack of objective assessment tools for PND, and treating physicians must rely on subjective complaints and validated patient-reported outcome instruments to determine treatment efficacy 5.