Coughing

Coughing is a reflex that helps clear the airways of irritants, mucus, and foreign material. It begins with stimulation of irritant receptors in the airways, sending signals via the vagus nerve to the brainstem, which orchestrates a forceful expiration against a closed glottis followed by sudden opening of the vocal cords and airways. A cough can be voluntary or involuntary and varies in strength and duration.

Coughs are commonly classified by duration: acute (<3 weeks), subacute (3–8 weeks), and chronic (>8 weeks). Most acute coughs are caused by viral infections, but persistent coughing can arise from postnasal drip, asthma, chronic obstructive pulmonary disease, bronchitis, gastroesophageal reflux, allergies, or exposure to tobacco smoke and other environmental irritants. Less common causes include pneumonia, pertussis, and lung cancer.

Evaluation focuses on history and examination, with attention to red flags such as chest pain, coughing up blood, fever with illness lasting longer than a few days, unexplained weight loss, or coughing in very young children or older adults. When indicated, investigations may include chest imaging and, for suspected asthma or COPD, spirometry.

Management targets the underlying cause and symptomatic relief. Many acute coughs resolve with supportive care alone. Medications such as antitussives (for example, dextromethorphan) may be used short term; expectorants and other agents have variable benefit. Inhaled therapies may help asthma or COPD–related cough. Nonpharmacologic measures include fluids, humidified air, throat lozenges, and, in certain settings, honey for children over one year. Cough suppression is generally avoided when a productive cough is needed.

Most coughs improve within days to weeks; chronic cough requires medical assessment to identify an underlying condition.