Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain a yellow coating on tongue needs not to be thrush as Thrush commonly represents as a thick white coating over the tongue.. Yellow coating is commonly suggestive of poor oral hygiene and accumulation of dead cells, debris and accumulation of bacteria and fungus over tongue.. I would therefore suggest you to consult an Oral Physician and get evaluated and he can do a clinical evaluation and also if needed a microscopic examination of the scraping from the coating can be done to confirm the cause.. In case if it is still thrush then an antifungal oral medication like Fluconazole along with nystatin mouthwash and clotrimazole lozenge along with plenty of probiotics like Yoghurt and garlic will be advised and proper investigations like blood tests will be done to rule out the exact cause for the infection and the underlying cause will also need to be treated.. In case if it is not thrush then cleaning the tongue with a tongue scraper daily, gargling with 1:1 solution of hydrogen peroxide and water and maintaining a good oral hygiene along with eating more of raw foods and fruits will help as it will clean the tongue by frictional action.. Next part of your question is recurring coughing that can be due to allergies, bronchitis and chronic upper respiratory tract infection etc.. In your case it seems to be due to allergic reaction to pollen and for it you can take anti allergics like benadryl or levocetrizine and cough expectorants.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.