Dry itchy throat with coughing... Been going on for 6 months?

I have been coughing for about 6 months now, and most of the time it's dry, but sometimes I bring stuff up. My throat is extremely itchy and has caused me to cough everyday for 6 months now. I've been to the doctors twice, and was diagnosed with Bronchitis. Medication was given to me, along with an inhaler, and the coughing has not stopped. The 2ND time I went to the doctors, I had a throat infection, and was given a breathing treatment at the hospital, along with antibiotics and cough medicine. I was also given another inhaler because my other one had run out. The antibiotics took away the infection, but the coughing hasn't stopped at all.. My throat continues to itch, and still causes me to cough. Anyone know what is wrong? My family doctor says that it may be allergies, but I doubt it because the coughing started back in January. Thank you.