A runny nose with cough is most commonly caused by a viral upper respiratory infection like the common cold, but it can also occur due to allergies, sinus infection, or irritation from dust, smoke, or weather changes. In most cases, it is mild and improves within a few days with rest, fluids, and simple care, but symptoms like fever, thick yellow/green mucus, or persistent cough may suggest a bacterial infection or sinus involvement. Allergies are more likely if you have sneezing, clear nasal discharge, and itching. Supportive treatment such as steam inhalation, warm fluids, and over-the-counter medicines like Paracetamol for fever or discomfort and Cetirizine for allergy symptoms can help relieve symptoms. If symptoms last more than a week, worsen, or are associated with breathing difficulty or high fever, it is important to consult a doctor for proper evaluation and treatment.