For immediate relief from a runny nose, over-the-counter antihistamines like Cetirizine or Loratadine can help, along with saline nasal sprays to clear congestion. However, because your symptoms are recurrent, they may be caused by allergies (allergic rhinitis) or chronic sinusitis rather than repeated common colds. I highly recommend consulting a doctor or allergist for a proper diagnosis. Avoid using over-the-counter decongestant nasal sprays for more than three consecutive days, as they can cause rebound congestion. A healthcare professional can help identify the root cause and prescribe targeted treatment.

For a dry cough caused by a dust allergy, you should treat both the allergy and the cough. A non-drowsy antihistamine (such as cetirizine, loratadine, or fexofenadine) will block the allergic reaction. To quiet the cough, you can take an oral cough suppressant containing dextromethorphan. Additionally, using a fluticasone nasal spray can reduce post-nasal drip, which often triggers the cough. Try to stay well-hydrated and minimise dust exposure. If your cough persists for more than two weeks, or if you develop wheezing or shortness of breath, please consult a doctor for a physical examination.