Yes it can. I have had problems for a while with constant sore throats, sinus problems, acid reflux and was diagnosed in May finally after all of these years with Asthma from a doctor who specialized in it (my regular doctor told me a year ago i didnt have it because I wasnt "wheezing" even though I had a feeling that i did have it, but according to the allergy doctor, one doesnt have to wheeze to have asthma so i have been walking around for some time feeling horrible, thank goodness for this doctor for helping me. I was told by the doctor that i have to clear away any infection and its good to do the sinus washes as it is connected to the upper respiratory system and will clear away any upper respiratory problems so they go hand in hand. I was on antibiotics for a long while, nasal washes, antihistamine spray, Advair, etc......I also had acid reflux due to post nasal drip and was put on a stomach medicine. With all of the things going on with me it did cause the asthma according to the doctor. Right now Im doing much better but still have flare ups every now and then. I faithfully do the nasal washes and I dont have any problems in the past two weeks. Now i used to have sinus & constant sore throat problems i would say for the past few years so the progress has been amazing. Also my diet wasnt great and i was put on an anti fungal pills for about a week, all in all all of these things helped tremendously as my system was way out of whack. Find someone who will work with you and not just cover up the problems.
