A cough lasting several years requires a thorough medical evaluation to determine its underlying cause. Common causes include chronic bronchitis, asthma, chronic obstructive pulmonary disease (COPD), or long-term exposure to irritants such as smoking or pollution. It is advisable to consult a pulmonologist for a detailed assessment, which may include a chest X-ray, lung function tests, a CT scan, and possibly allergy screening. Treatment may include inhalers, bronchodilators, and antiallergic or antihistamine medications, along with lifestyle measures such as quitting smoking, staying well hydrated, and avoiding exposure to allergens.