My mother is 88 and is in a nursing home. About 2 months ago she started with thick, clear string phlegm. It is constant and is now affecting her health. She has lost weight as she is having difficulty eating and drinking because the phlegm is so thick she throws up. The doctor and nurses say it is allergy related and have prescribed mucinex,, claritin, zertec, and flonaise, at different times, but nothing seems to be working. Should I have her tested to see what allergies she has or what she may be allergic to? I don t know what to do about it.