Hi,
I'm a dad not a mom but saw this and thought you might like a comment from someone who knows a little. As a 1 year old, your son likely likely consumes large amounts of dairy products, milk, cheese, etc. Milk causes mucus so could be a factor. I have copd and if I get a cold, must stop using milk or cream in coffee, no ice cream, etc. Your allergist may suggest a soy milk substitute. Also, it is very possible that another allergy is causing a problem. Dust mites from older bedding, cat or dog dandruff, just a host of things. The allergist could possibly do tests for sensitivity to known allergens, which include the above, and lots more, for example, new carpeting or drapes, from chemicals, or old carpeting or drapes for dust, etc. Next, is there any chance your living quarters have any mold? Some people are very allergic to molds. Housing and zoning have actually encouraged mold by making the quarters air tight to save energy but that makes it almost impossible to shed excess moisture hence mold grows and rotting windows or wood framing feed the problem. Finally, on a positive note, water thins mucus so encouraging water drinking is good. I know it is difficult to have youngsters drink what we want but it really thins and makes easier to expel mucus. You are certainly right to be concerned. The coughing is physically demanding and interferes with quality sleep. I am not involved in the medical field. Just a dad who knew a little. Please also remember, if your pediatrician isn't able to give you a correct treatment, there is the UofM and the Mayo Clinic to consider for second opinions. Best regards, JMA