A dry cough lasting 5 months is a chronic cough and needs proper evaluation, as it may be due to conditions like asthma, gastroesophageal reflux disease, or post-nasal drip/allergy. Since levocetirizine and syrups haven?t helped, you should see a doctor for tests like a chest X-ray or lung function test; treatment may require inhalers, anti-reflux medicines, or other targeted therapy. Avoid dust, smoking exposure, and cold triggers, and don?t keep taking medicines without diagnosis.