I know this answer is over a year later, but just in case someone else is currently researching...my son had a cough that wouldn't go away no matter what. He did lots of antibiotics, was cleared for asthma -you name it. We tried allergy medicines, cough medicines, everything you can think of. Well, it turned out that he had acid reflux. Not the kind that gives you heartburn per se, but the kind known as silent reflux (LPR). Little particulates of acid and non-acid stomach contents are aspirated into the sinuses and lungs causing cough, infections, etc. We put our son on prescription acid reflux meds and the cough went away. Well, every 6 months it would come back. A few months ago it got really bad and the non-stop gagging started. Our son had been seeing a pediatric GI, but we took him to an ENT, and that doc tested him for allergies. Lo and behold, he is allergic to wheat, dairy, eggs, peanuts. Then we find out about gluten (in wheat & all grains to some degree). He is allergic to gluten & gluten can cause acid reflux & lots of other nasty little health problems (you wouldn't believe all the things). We have taken him off the foods he is allergic to and guess what? Symptoms gone! My husband has suffered from eczema all his life & his hair started to fall out. He stopped the gluten & his problems went away. Now...blood tests are not sufficient (they can produce false negatives). People with celiac (caused by gluten allergy), have blood tested negative for gluten allergy. However, when genetically tested the proof was 100% positive in their genes! Genetic testing is the wave of the future. Gluten allergy is still poorly understood by the medical community. A lot of doctors think gluten allergy only causes celiac disease, so if you don't have the symptoms of celiac disease, they dismiss gluten allergy as a possibility. Check out a website I love called glutenfreesociety.org Hope this helps! We were going nuts for a long time trying to figure out what was going on with my son.